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Fan-Coil Units

Written and maintained by SynC.

Rev4
IssuedOct 17, 2026
LicenseCC BY 4.0
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1 Scope

NOTE A fan-coil unit is the smallest complete air conditioner on a central water plant: a fan, a filter, one or two finned-tube coils, and a drain pan in one casing, placed in or next to the zone it serves and conditioning only the air of that zone. It takes chilled water and heating water from the building's plant and returns them, and it moves the room's own air across the coils. What separates it from an air terminal unit is that it recirculates room air rather than metering central air, and what separates it from a packaged terminal or split unit is that it carries no refrigeration circuit of its own. (1.1)
NOTE The following are covered when they form part of the unit: (1.2)
  • Casing, cabinet, liner, access provisions, and exterior finish
  • Chilled water and heating water coils, including the single changeover coil of a 2-pipe unit
  • Supplementary electric resistance heaters with their safety devices
  • Fan, motor, and speed control
  • Filters and filter access
  • Primary drain pan, condensate connection, and an integral condensate pump where furnished
  • Ventilation air connection and its damper where furnished with the unit
  • The coil connection package and the control package where they are factory-furnished, as a furnish and mounting decision
  • The integral risers of a stacked high-rise unit
  • Factory testing, delivery, installation, startup, field verification, identification, warranty, and spare parts
NOTE The following are outside this standard: (1.3)
  • Central station air handling units, covered by Air Handling UnitsAir Handling UnitsResolves to the current adopted revision.sync/air-handling-units
  • Air terminal units, covered by Air Terminal UnitsAir Terminal UnitsResolves to the current adopted revision.sync/air-terminal-units, and their variable-volume layer, covered by Variable Air Volume TerminalsVariable Air Volume Terminal UnitsResolves to the current adopted revision.sync/variable-air-volume-terminals
  • Fan-coil units with a refrigerant coil matched to a remote condensing unit, which are split systems covered by Split System Air ConditionersSplit-System Air Conditioners and Heat PumpsResolves to the current adopted revision.sync/split-system-air-conditioners, and the indoor units of a variable refrigerant flow system, covered by Variable Refrigerant Flow SystemsVariable Refrigerant Flow (VRF) SystemsResolves to the current adopted revision.sync/variable-refrigerant-flow-systems
  • Active and passive chilled beams, covered by Chilled BeamsActive and Passive Chilled BeamsResolves to the current adopted revision.sync/chilled-beams
  • Water-source heat pump units on a condenser water loop, covered by Water Source Heat PumpsWater-Source Heat PumpsResolves to the current adopted revision.sync/water-source-heat-pumps
  • Through-the-wall packaged terminal air conditioners and heat pumps, covered by Packaged Terminal Air ConditionersPackaged Terminal Air ConditionersResolves to the current adopted revision.sync/packaged-terminal-air-conditioners
  • Heating-only cabinet and propeller units, fin-tube radiation, and convectors, covered by Terminal Heating UnitsTerminal Heating UnitsResolves to the current adopted revision.sync/terminal-heating-units
  • Dedicated outdoor air units that condition the ventilation air these units depend on, covered by Dedicated Outdoor Air SystemsDedicated Outdoor Air SystemsResolves to the current adopted revision.sync/dedicated-outdoor-air-systems
  • Close-control units for data centers and equipment rooms, covered by Computer Room Air ConditioningComputer Room Air Conditioning UnitsResolves to the current adopted revision.sync/computer-room-air-conditioning
  • Classroom unit ventilators that take their outdoor air through an integral damper and economizer
  • Replacement coils and coils procured separately from the unit, covered by Heating And Cooling CoilsHeating and Cooling CoilsResolves to the current adopted revision.sync/heating-and-cooling-coils
  • Hydronic piping from the plant to the unit connection, covered by Hydronic PipingHydronic PipingResolves to the current adopted revision.sync/hydronic-piping, the general-duty valves in it, covered by HVAC Piping ValvesGeneral-Duty Valves for HVAC PipingResolves to the current adopted revision.sync/hvac-piping-valves, and the balancing valves, strainers, and pressure-independent control valves, covered by Hydronic SpecialtiesHydronic SpecialtiesResolves to the current adopted revision.sync/hydronic-specialties
  • Two-way and three-way control valves and their actuators, thermostats, zone sensors, and condensate overflow switches as devices, covered by HVAC Controls InstrumentationHVAC Instrumentation and Control DevicesResolves to the current adopted revision.sync/hvac-controls-instrumentation
  • The zone controller, the network, and the sequences of operation, covered by Building Automation SystemBuilding Automation SystemResolves to the current adopted revision.sync/building-automation-system
  • Condensate drain piping, traps, and lift pumps beyond the pan outlet, covered by Condensate Drainage PipingHVAC Condensate Drainage PipingResolves to the current adopted revision.sync/condensate-drainage-piping
  • Field-applied insulation of piping and risers, covered by Mechanical InsulationMechanical InsulationResolves to the current adopted revision.sync/mechanical-insulation
  • Ductwork beyond the unit connections, covered by HVAC DuctworkHVAC DuctworkResolves to the current adopted revision.sync/hvac-ductwork, and the diffusers and grilles at the room boundary of a ducted unit, covered by HVAC Air Distribution DevicesHVAC Air Distribution DevicesResolves to the current adopted revision.sync/hvac-air-distribution-devices
  • Hangers, isolators, and seismic restraint devices, covered by Hangers And SupportsHangers and Supports for Mechanical Piping and EquipmentResolves to the current adopted revision.sync/hangers-and-supports and Vibration Isolation And Seismic RestraintVibration Isolation and Seismic RestraintResolves to the current adopted revision.sync/vibration-isolation-and-seismic-restraint
  • Testing, adjusting, and balancing of the completed systems, covered by Testing Adjusting And BalancingTesting, Adjusting, and Balancing for HVACResolves to the current adopted revision.sync/testing-adjusting-and-balancing
NOTE A fan-coil unit conditions recirculated room air and delivers no outdoor air unless a ventilation air connection is furnished and served. The ventilation rate the space requires is satisfied by the equipment that delivers that air, and nothing in this standard satisfies a ventilation requirement on its own. (1.4)
1.5 Where the served space requires outdoor air, the ventilation air shall be delivered by equipment furnished under Dedicated Outdoor Air SystemsDedicated Outdoor Air SystemsResolves to the current adopted revision.sync/dedicated-outdoor-air-systems, Air Handling UnitsAir Handling UnitsResolves to the current adopted revision.sync/air-handling-units, or Makeup Air UnitsMakeup Air UnitsResolves to the current adopted revision.sync/makeup-air-units, or through a ventilation air connection on the unit as indicated in the datasheet.
1.6 Each unit shall be furnished as a complete assembly by a single manufacturer, who shall be responsible for the air-side, hydronic, acoustic, and electrical performance of the unit as a whole.
NOTE Per-tag quantities are scheduled and project-wide policy is selected in the datasheet. Airflows, static pressures, capacities, water temperatures, heater ratings, and electrical characteristics vary with every unit on the project and live on the fan-coil unit schedule; the construction, options, furnish, and warranty decisions that apply to every unit on the project are made once here. (1.7)
1.8 Where a requirement of this standard conflicts with a requirement of a standard that governs a connected system, the Engineer of Record shall make the initial determination of which requirement governs.

2 Referenced Standards

2.1 Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
2.2 Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
Standard Title
ANSI/AHRI 440 (I-P) Performance Rating of Fan-Coil Units
ANSI/AHRI 410 Performance Rating of Forced-Circulation Air-Cooling and Air-Heating Coils
ANSI/AHRI 350 Sound Performance Rating of Non-ducted Indoor Air-conditioning Equipment
ANSI/AHRI 260 (I-P) Sound Rating of Ducted Air Moving and Conditioning Equipment
ANSI/AHRI 885 Procedure for Estimating Occupied Space Sound Levels in the Application of Air Terminals and Air Outlets
ANSI/ASHRAE 62.1 Ventilation and Acceptable Indoor Air Quality
ANSI/ASHRAE/IES 90.1 Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings
ANSI/ASHRAE 52.2 Method of Testing General Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size
ANSI/ASHRAE 202 Commissioning Process for Buildings and Systems
ANSI/ASA S12.2 Criteria for Evaluating Room Noise
ANSI/AMCA 210 / ANSI/ASHRAE 51 Laboratory Methods of Testing Fans for Certified Aerodynamic Performance Rating
ANSI/AMCA 300 Reverberant Room Method for Sound Testing of Fans
NFPA 90A Standard for the Installation of Air-Conditioning and Ventilating Systems
NFPA 70 National Electrical Code
UL 60335-2-40 Household and Similar Electrical Appliances, Safety, Part 2-40: Particular Requirements for Electrical Heat Pumps, Air-Conditioners and Dehumidifiers
UL 1995 Heating and Cooling Equipment
UL 2043 Fire Test for Heat and Visible Smoke Release for Discrete Products and Their Accessories Installed in Air-Handling Spaces
ASTM A653 Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process
ASTM A240 Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip
ASTM B75 Standard Specification for Seamless Copper Tube
ASTM B88 Standard Specification for Seamless Copper Water Tube
ASTM C1071 Standard Specification for Fibrous Glass Duct Lining Insulation (Thermal and Sound Absorbing Material)
ASTM C1338 Standard Test Method for Determining Fungi Resistance of Insulation Materials and Facings
ASTM E84 Standard Test Method for Surface Burning Characteristics of Building Materials
ASTM B117 Standard Practice for Operating Salt Spray (Fog) Apparatus
NEMA MG 1 Motors and Generators
NEMA 250 Enclosures for Electrical Equipment (1000 Volts Maximum)
ASCE/SEI 7 Minimum Design Loads and Associated Criteria for Buildings and Other Structures

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following for the Engineer of Record's review and return, and shall not release any unit for fabrication until the submittal covering it has been reviewed and returned:
  • Unit schedule keyed to the mechanical drawings, listing for each tag the arrangement, enclosure, piping arrangement, airflow at the design fan speed, external static pressure, total and sensible cooling capacity, heating capacity, coil rows, entering and leaving water temperatures and flows, electric heater rating where furnished, electrical characteristics, and operating weight
  • Certified performance data for each unit configuration, identifying the rating standard and the certification program under which the data is published
  • Coil selection data giving row count, fin spacing, tube and fin material, working pressure rating, entering and leaving air and water conditions at the scheduled fan speed, capacity, and air-side and water-side pressure drop
  • Sound power data in octave bands at the scheduled fan speed and external static pressure, with the occupied-space sound level for each scheduled zone and the room correction values used to produce it
  • Fan and motor data giving wheel type, motor type, nameplate power, electrical characteristics, speed control means, and the fan input power at the design operating point
  • Filter data giving media type, efficiency rating, depth, and the access arrangement
  • Drain pan data giving material, slope, insulation, and the overflow protection furnished
  • Electric heater data giving element construction, capacity, stage count, electrical characteristics, the minimum airflow for heater operation, and the safety devices furnished
  • Coil connection package data giving each component furnished, its size and flow setting, and the party that mounts it
  • Control package data giving each control device furnished with the unit, the party that mounts and wires it, and the terminal strip wiring diagram
  • Riser data for stacked units giving riser material, size, insulation, joint method, and the expansion provision at each floor
  • Shop drawings showing each unit in plan and section with every field connection point dimensioned, the required service clearance, the filter and access panel locations, and the operating weight
  • Evidence of the Nationally Recognized Testing Laboratory listing for each unit configuration furnished
Action Submittals Requiredcheckbox
☑ Unit schedule keyed to the mechanical drawings
☑ Certified performance data for each unit configuration
☑ Coil selection data
☑ Sound power data with occupied-space levels
☑ Fan and motor data with fan input power
☑ Filter data
☑ Drain pan and overflow protection data
☐ Electric heater data with safety devices
☑ Coil connection package data
☑ Control package data with wiring diagram
☐ Riser data for stacked units
☑ Shop drawings with clearances and field connections
☑ Nationally Recognized Testing Laboratory listing evidence
3.1.2 Where the Contractor proposes a unit from a manufacturer other than the one on which the design was based, the submittal shall include a side-by-side comparison of airflow at the scheduled external static pressure, total and sensible capacity at the scheduled water conditions, sound power, fan input power, and the casing dimensions and connection locations of the proposed and the scheduled unit.
3.1.3 Where a proposed substitution changes the casing dimensions, the connection locations, or the required service clearance of any unit, the submittal shall identify every ceiling, piping, duct, and riser coordination item affected.

3.2 Closeout Submittals

3.2.1 Before the date of Substantial Completion, the Contractor shall submit the following:
  • Operation and maintenance manuals covering installation, operation, maintenance, and troubleshooting, with the recommended preventive maintenance interval for each serviceable component and the filter size and rating for each unit
  • As-built unit schedule recording every field substitution and every field modification to the submitted configuration, together with the review documentation for each
  • Factory test record for each unit, including the coil leak test certification
  • Field startup and verification record for each unit, giving the measured airflow at each fan speed, the water flow, the drainage verification, the overflow protection test, and the point-by-point verification of the control interface
  • Warranty documentation from the unit manufacturer and from each separately warranted component supplier
Closeout Submittals Requiredcheckbox
☑ Operation and maintenance manuals with filter sizes
☑ As-built unit schedule with field modifications
☑ Factory test record for each unit
☑ Field startup and verification record for each unit
☑ Warranty documentation

4 Quality Assurance

4.1 Manufacturer Qualifications

4.1.1 Units shall be produced by a manufacturer that has continuously produced factory-fabricated fan-coil units for commercial service for not less than the number of years indicated in the datasheet.
Manufacturer Experiencerange
Not less than
years
3510152025
4.1.2 The manufacturer shall publish a catalog covering the full range of units supplied to the project, including rated performance at each cataloged size and fan speed.
4.1.3 The manufacturer shall maintain replacement motors, coils, drain pans, filters, and control components for the units supplied for not less than ten years after the date of Substantial Completion.
4.1.4 All fan-coil units on the project shall be furnished by a single manufacturer so that the service access pattern, the control interface, and the spare parts inventory are common across the installation.
4.1.5 Where the Contract Documents divide the project into separately bid phases or buildings, the single-manufacturer requirement applies within each phase or building rather than across the project.

4.2 Basis of Published Performance Data

4.2.1 The basis on which the performance of each unit configuration is established shall be as indicated in the datasheet.
Basis of Certified Performance Ratingsradio
● AHRI 440 certified ratings for every unit configuration furnished
○ AHRI 440 certified ratings, with independent laboratory test data by the AHRI 440 method accepted for a configuration outside the certified range
○ Independent laboratory test data by the AHRI 440 method for every unit configuration furnished
4.2.2 Cooling capacity, sensible cooling capacity, heating capacity, airflow, and fan input power cited for any unit shall be established by the selected basis at the standard rating conditions of ANSI/AHRI 440 and corrected to the scheduled conditions by the manufacturer's published selection method.
4.2.3 The certification mark or the independent laboratory test report reference, as applicable to the basis selected, shall appear on the product data submitted for each unit configuration.
NOTE The certification program covers a defined range of sizes and configurations, and a manufacturer in the program can still catalog a blower coil unit or a large stacked unit outside that range. Ratings inside the range are verified by a third party on a sampling basis, while ratings outside it rest on the manufacturer's own test data, which is the difference the engineer is buying when the basis is selected. (4.2.4)
4.2.5 Where the parties disagree whether a proposed unit configuration falls within the certified range, the Engineer of Record shall make the initial determination.

4.3 Product Listing and Labeling

4.3.1 The complete unit, including every factory-installed electrical component, shall be listed and labeled by a Nationally Recognized Testing Laboratory under the standard indicated in the datasheet.
Unit Safety Listing Standardradio
○ UL 60335-2-40
○ UL 1995
4.3.2 Units listed to UL 1995 are acceptable only where the Authority Having Jurisdiction accepts that listing for the equipment furnished.
4.3.4 Electric heaters furnished within the unit shall be listed as part of the unit and shall comply with NFPA 70 Article 424.
4.3.5 Units and their factory-furnished accessories installed in a ceiling plenum or other air-handling space used to convey environmental air shall comply with the heat and smoke release limits of UL 2043 or shall be constructed of materials NFPA 90A accepts for that space.
4.3.6 The listing label shall be affixed to the casing exterior in a location that remains visible after installation.

4.4 Pre-Installation Conference

4.4.1 Before installation of fan-coil units begins, the Contractor shall convene a pre-installation conference attended by the mechanical, piping, controls, and electrical subcontractors, the testing and balancing agent, and the commissioning authority where one is engaged.
4.4.2 The pre-installation conference agenda shall include service clearance and access panel coordination, condensate drain routing and slope at every unit, the coil connection package and who mounts it, control device mounting and wiring responsibility, riser alignment and floor penetration sequence for stacked units, and the schedule for airflow and water flow verification.
NOTE A fan-coil unit is small enough that its coordination problems are routinely left for the field, and the field discovers them one at a time above a finished ceiling: a drain that cannot slope to the riser, a valve package that does not clear the joist, a filter that cannot come out past the sprinkler main. The conference is where those are found once instead of two hundred times. (4.4.3)

5 Service Environment

5.1 Unit locations, tags, and orientations are as indicated on the mechanical plans.
5.2 The supply discharge direction, the return air arrangement, and the coil connection hand of each unit shall be as indicated on the fan-coil unit schedule.
5.3 Units shall be suitable for continuous operation at an ambient dry-bulb temperature from 50 °F to 104 °F and at a relative humidity up to 90% without condensation on the casing exterior or the control enclosure.
5.4 Units are not weather-resistant as manufactured and shall not be installed outdoors or in any location exposed to precipitation, wind-driven moisture, or freezing temperatures.
5.5 Where a unit is installed in a space whose ambient conditions fall outside the range stated above, including an unconditioned mechanical closet open to outdoor air, a parking structure, or a natatorium, the Contractor shall obtain the manufacturer's written confirmation of suitability, together with any required change to the casing, the coil protection, the control enclosure, or the condensate provisions, before the unit is released for fabrication.
5.6 The control enclosure rating shall be as indicated in the datasheet.
Control Enclosure Ratingselect
NEMA 1, general purpose
NEMA 1 with a gasketed cover
NEMA 4X, watertight and corrosion resistant
5.7 Control enclosures on units installed in a natatorium, a parking structure, a kitchen, or any space subject to hosing or to a corrosive atmosphere shall be rated NEMA 4X.
5.8 Control enclosures on units installed in a space subject to dripping or to condensation on surfaces above the unit shall be rated NEMA 1 with a gasketed cover or higher.
NOTE The enclosure rating is a question about the room the unit sits in rather than about the unit, and almost every fan-coil unit sits in a conditioned ceiling or a finished room, where a general-purpose enclosure is the right answer. The gasketed cover keeps a drip from reaching the terminal strip in a plenum shared with piping that sweats; the corrosion-resistant enclosure keeps a chlorinated or exhaust-laden atmosphere off the contacts, at the cost of an enclosure that is harder to open for service. (5.9)
5.10 Capacity and airflow ratings shall be corrected for AltitudeAltitudeParameterEach project supplies its own value.altitude in accordance with the manufacturer's published correction factors.

6 Unit Configuration

NOTE The fan-coil products in the market are combinations of a small number of independent decisions: whether the unit stands or hangs, whether its casing is finished for the room or hidden above a ceiling or in a closet, whether the water risers are built into it, and whether it takes a ventilation air connection. A vertical stacked hotel unit, for example, is a vertical concealed unit with integral risers. Selecting each decision separately keeps every combination the catalogs offer available and keeps each decision queryable on its own. (6.1)

6.2 Unit Arrangement

6.2.1 The unit arrangement shall be as indicated in the datasheet.
Unit Arrangementradio
○ Horizontal, with the fan and coil in a flat casing and horizontal discharge
○ Vertical, with the fan below the coil and upward discharge
NOTE A horizontal unit hangs above a ceiling or along a wall near the ceiling and takes the least floor and wall area in the room, at the cost of putting every service point overhead, where a filter change, a drain cleaning, and a valve repair each need a ladder and a ceiling opening. A vertical unit stands on the floor or in a chase, keeps its filter and its valve package at a reachable height, and takes floor area or wall length in every room it serves. (6.2.2)

6.3 Cabinet Enclosure

6.3.1 The cabinet enclosure shall be as indicated in the datasheet.
Cabinet Enclosureselect
Exposed, with a finished cabinet and integral discharge and return grilles in the room
Concealed, with an unfinished casing for installation above a ceiling, in a closet, or in a chase
Recessed, with the casing in a ceiling or wall pocket and a finished front in the room
NOTE An exposed cabinet unit needs no ceiling, no chase, and no ductwork, and it is the arrangement that fits a renovation of a building with neither, at the cost of a visible cabinet in every room and a sound path with nothing between the fan and the occupant. A concealed unit disappears into the ceiling or the closet and can be ducted to outlets where they are wanted, and it pays for that with an access panel, a duct connection, and external static pressure the fan has to overcome. A recessed unit is the compromise, with the casing out of the room and a finished grille face at the ceiling or the wall, and it needs the pocket depth and the clearance behind it that the casing requires. (6.3.2)
6.3.3 A concealed unit shall be furnished with a duct connection collar at the discharge and, where a ducted return is scheduled, at the return.
6.3.4 An exposed cabinet unit shall be furnished with a finished front panel that is removable or hinged for filter and coil access without tools other than a key or a standard hand tool.
6.3.5 A recessed unit shall be furnished with a mounting frame or trim that closes the pocket opening and a finished front that is removable for filter and coil access from the room.

6.4 Integral Riser Construction

6.4.1 The riser construction shall be as indicated in the datasheet.
Integral Riser Constructionradio
● Field-piped unit connected to risers installed under the hydronic piping scope
○ Stacked unit with chilled water, heating water, and condensate risers built into the casing and joined unit to unit
NOTE A stacked unit carries its risers inside the casing, so setting the unit sets the risers, and the floor-to-floor riser joints are made at the unit rather than in a separate chase by a separate trade. On a tall building with one unit per room stacked floor over floor, that removes a pipe shaft, a riser coordination exercise, and a trade from every floor. The price is that the unit becomes part of the piping system: its casing has to be plumb and aligned floor over floor, its risers have to accommodate the building's thermal and structural movement, and a riser repair means opening a finished room. (6.4.2)
6.4.3 Requirements for the risers of a stacked unit are stated in the stacked riser construction article of this standard.

6.5 Ventilation Air Connection

6.5.1 The ventilation air connection furnished with the unit shall be as indicated in the datasheet.
Ventilation Air Connectionselect
None, with the unit recirculating room air only
Ducted connection for conditioned ventilation air delivered from a dedicated outdoor air unit
Outdoor air inlet collar with a manual balancing damper
Outdoor air inlet collar with a motorized damper interlocked to close when the fan stops
NOTE A unit with no connection recirculates room air and leaves ventilation entirely to another system, which keeps the unit simple and keeps raw outdoor air away from its coil. A ducted connection from a dedicated outdoor air unit brings in air that is already filtered, dehumidified, and tempered, so the fan-coil coil sees only the room load and the unit needs no freeze protection of its own. An outdoor air inlet collar brings untreated outdoor air through the unit's own filter and coil, which is the least equipment for the ventilation it delivers and the arrangement that puts a freezing airstream and a wet airstream on the coil, so the coil, the filter, and the damper all have to be selected for it. A motorized damper closes the opening when the fan is off, which stops the stack-driven infiltration and the freezing draft a manual damper admits through an idle unit. (6.5.2)
6.5.3 Where a ducted connection for conditioned ventilation air is selected, the connection shall be sized for the scheduled ventilation airflow at the static pressure available from the dedicated outdoor air system, and the two systems shall be coordinated with Dedicated Outdoor Air SystemsDedicated Outdoor Air SystemsResolves to the current adopted revision.sync/dedicated-outdoor-air-systems.
6.5.4 Where an outdoor air inlet collar is selected, the unit shall be furnished with the coil freeze protection stated in the hydronic coils article of this standard.
6.5.5 Where an outdoor air inlet collar is selected, the filter shall be located so that the outdoor air passes through it before reaching the coil.
6.5.6 Where an outdoor air inlet collar is selected, the louver, the wall sleeve, and the duct from the exterior wall to the unit collar shall be furnished under Louvers And DampersLouvers and DampersResolves to the current adopted revision.sync/louvers-and-dampers and HVAC DuctworkHVAC DuctworkResolves to the current adopted revision.sync/hvac-ductwork.
6.5.7 Where an outdoor air inlet collar is selected, the ventilation airflow through it shall be verified in accordance with Testing Adjusting And BalancingTesting, Adjusting, and Balancing for HVACResolves to the current adopted revision.sync/testing-adjusting-and-balancing.

7 Piping Arrangement and Heat Source

7.1 Piping Arrangement

7.1.1 The piping arrangement shall be as indicated in the datasheet.
Piping Arrangementradio
○ 2-pipe, with one coil served by one supply and one return
○ 4-pipe, with a chilled water coil and a heating water coil each served by its own supply and return
NOTE A 2-pipe unit has one coil and one pair of pipes, so the whole building is in cooling or in heating at once and changes over on a plant decision, and no zone can call for the other mode until it does. A 4-pipe unit carries both coils and both pairs of pipes to every unit, so any zone can cool while its neighbor heats, at the cost of two more pipes, two more valves, and a larger casing at every unit. The split follows the building: where the loads are uniform and the seasons are distinct, the 2-pipe system does what the 4-pipe system does at a fraction of the piping; where a sunny perimeter and a shaded perimeter, or a conference room and a server closet, need opposite modes on the same afternoon, only the 4-pipe system can serve both. (7.1.2)
7.1.3 A 2-pipe unit shall be selected so that the single coil delivers the scheduled cooling capacity at the scheduled chilled water conditions and the scheduled heating capacity at the scheduled heating water conditions.
7.1.4 A 4-pipe unit shall be furnished with the chilled water coil and the heating water coil as separate coils with separate connections, and the heating water coil shall be located downstream of the chilled water coil in the direction of airflow.
NOTE Placing the heating coil downstream of the cooling coil lets a 4-pipe unit reheat dehumidified air when a sequence calls for it, and keeps the heating coil out of the condensing airstream, where a warm fin surface would otherwise evaporate condensate back into the supply air. (7.1.5)

7.2 Two-Pipe Coil Service

7.2.1 Requirements in this article apply where a 2-pipe piping arrangement is selected in the datasheet.
7.2.2 The service of the 2-pipe coil shall be as indicated in the datasheet.
Two-Pipe Coil Serviceradio
○ Changeover, carrying chilled water in the cooling season and heating water in the heating season
○ Chilled water only, with any heating furnished by the supplementary electric heater
NOTE A changeover coil is selected at both water conditions, and the plant decides which it carries. A chilled water only coil is a cooling coil that never sees heating water, which is the arrangement on a building whose heat is electric at the unit or comes from a separate system, and it needs no changeover control, no changeover sensor, and no plant decision about when the season turns. (7.2.3)
7.2.4 Where a changeover service is selected, the control package shall include a means of sensing the supply water temperature at or near the unit so that the controller can determine the mode in which the coil is operating.
7.2.5 Where a chilled water only service is selected and the zone requires heating, the supplementary electric heater shall be furnished.

7.3 Supplementary Electric Heat

7.3.1 The supplementary electric heater shall be furnished as indicated in the datasheet.
Supplementary Electric Heatradio
○ Not furnished
○ Electric resistance heater furnished within the unit
NOTE An electric heater at the unit brings heating to a zone without a heating water pipe, which on a chilled water only system is the only heat the zone has and on a changeover system is the heat available during the weeks the plant is still in cooling. It is bought with a branch circuit sized for the heater, a demand-coincident electrical load at every unit, and whatever limit the energy code places on electric resistance heating for the building type and climate. (7.3.2)
7.3.3 The Engineer of Record shall confirm that the electric heater complies with the limits Adopted Energy CodeAdopted Energy CodeParameterEach project supplies its own value.adopted-energy-code places on electric resistance heating for the building type and climate before the heater is released for fabrication.
7.3.4 Requirements for the heater are stated in the electric heater article of this standard.

8 Capacity and Airflow Ratings

8.1 Capacity Rating Basis

8.1.1 Airflow, cooling capacity, sensible capacity, heating capacity, water pressure drop, and fan input power shall be stated for each scheduled unit at the scheduled fan speed, the scheduled external static pressure, the scheduled entering air conditions, and the scheduled entering and leaving water temperatures.
8.1.2 Where the scheduled conditions differ from the standard rating conditions of ANSI/AHRI 440, the manufacturer shall state in the submittal the correction method used and the certified rating from which each scheduled value was derived.
NOTE The certified rating is taken at one set of air and water conditions, and the capacity a unit delivers moves with every one of them: a higher entering wet-bulb raises the latent share and lowers the sensible share, a warmer chilled water supply cuts the total, a cooler heating water supply cuts the heating output steeply, and a fan speed below the rating speed reduces every quantity at once. A schedule written from catalog nominal capacities at standard conditions overstates what the unit delivers on the project's plant by an amount that depends on how far the plant is from the rating conditions. (8.1.3)
8.1.4 The sensible capacity stated for each unit shall be not less than the scheduled sensible load, and the total capacity shall be not less than the scheduled total load, at the scheduled conditions.

8.2 Scheduled Airflow and Static Pressure

8.2.1 The airflow at the design fan speed shall be as indicated in the datasheet.
Airflow at the Design Fan Speedrange
cfm
1005000
Per drawings — airflow as indicated on the fan-coil unit schedule (deferred by default)
8.2.2 The external static pressure at the design airflow shall be as indicated in the datasheet.
External Static Pressure at the Design Airflowrange
in. w.g.
01.5
Per drawings — external static pressure as indicated on the fan-coil unit schedule (deferred by default)
NOTE A unit with an exposed cabinet and integral grilles operates at the external static pressure of its own grilles and nothing else, and a concealed unit operates against the duct, the outlets, the return path, and any field-installed filter grille. The recurring field failure is a concealed unit selected at the free-discharge airflow of its exposed sibling, which then delivers a fraction of the scheduled airflow once the duct is on it, and the recovery is a higher fan speed that the sound selection never saw. (8.2.3)
8.2.4 Each unit shall deliver the scheduled airflow at the scheduled external static pressure at a fan speed not higher than the design fan speed, with the scheduled filter installed and clean.

8.3 Scheduled Capacities

8.3.1 The total cooling capacity shall be as indicated in the datasheet.
Total Cooling Capacityrange
Not less than
MBH
2200
Per drawings — cooling capacity as indicated on the fan-coil unit schedule (deferred by default)
8.3.2 The sensible cooling capacity shall be as indicated in the datasheet.
Sensible Cooling Capacityrange
Not less than
MBH
1.5160
Per drawings — sensible capacity as indicated on the fan-coil unit schedule (deferred by default)
8.3.3 The hydronic heating capacity shall be as indicated in the datasheet.
Hydronic Heating Capacityrange
Not less than
MBH
2300
Per drawings — heating capacity as indicated on the fan-coil unit schedule (deferred by default)
8.3.4 Each capacity shall be stated at the scheduled airflow, the scheduled entering air condition, and the scheduled entering and leaving water temperatures for that unit, and the water flow and water pressure drop at which it is achieved shall be stated beside it.

9 Hydronic Coils

9.1 Coil Construction

9.1.1 Coils shall be constructed of seamless copper tube to ASTM B75 mechanically expanded into plate fins to form a continuous metal-to-metal bond over the full finned length.
9.1.2 The row count and the fin spacing of each coil shall be the manufacturer's selection to deliver the scheduled capacity at the scheduled entering air and entering water conditions and the scheduled airflow, and shall be stated for each unit in the coil selection data.
NOTE Row count is where the plant's water temperatures meet the unit. A deeper cooling coil delivers the scheduled capacity on warmer chilled water and pulls more moisture out of the air at the same airflow, at the cost of a higher air-side pressure drop that the fan pays for at every hour and a higher water-side pressure drop that the pump pays for. A heating coil sized for a plant at 180 °F falls far short of its capacity on a plant designed around a condensing boiler or a heat pump at 130 °F, and the only recovery at the unit is a row the casing was not built to hold, so the count is selected against the project's scheduled water temperatures rather than against a catalog reference. (9.1.3)
9.1.4 The coil fin material shall be as indicated in the datasheet.
Coil Fin Materialradio
● Aluminum plate fin
○ Copper plate fin
9.1.5 The coil corrosion protection shall be as indicated in the datasheet.
Coil Corrosion Protectionselect
No coating
Baked phenolic dip coating over the fins and tubes
Electrodeposition coating over the fins and tubes
Polymer spray coating over the fins and tubes
NOTE An aluminum fin on a copper tube is the construction nearly every unit carries, and it serves for the life of the unit in a conditioned building. A copper fin removes the galvanic couple and the aluminum's vulnerability to chlorides, at a higher cost and weight, and it is the choice where the airstream carries salt or pool chemistry. A coating over either fin seals the whole coil surface against the atmosphere it sits in, with a dip coating giving the heaviest film and the largest capacity penalty, an electrodeposition coating giving the thinnest and most uniform film with the smallest penalty, and a spray coating falling between them and depending most on the applicator. The condition that selects any of them is an airstream that is corrosive, which a ventilation air connection to a coastal or industrial atmosphere, a natatorium, or a kitchen can make it. (9.1.6)
9.1.7 Where a coating is selected, the coated coil shall withstand a salt spray exposure to ASTM B117 for not less than 1,000 hours without blistering, and the manufacturer shall state the capacity derate of the coating in the coil selection data.
9.1.8 The coil working pressure rating shall be as indicated in the datasheet.
Coil Working Pressure Ratingrange
Not less than
psig
150200250300400
9.1.9 Coils shall be leak tested at the factory at not less than 1.5 times the specified working pressure rating with air under water or by an equivalent method, and the test shall be recorded in the factory test record.
9.1.10 Coil connections shall be sweat or threaded connections extended beyond the casing far enough for the coil connection package to be installed without cutting or modifying the casing, and the connection type and size shall be stated on the shop drawings.
9.1.11 Coils shall be furnished with a manual air vent at the high point of the coil and a drain connection at the low point, each accessible with the unit installed.
9.1.12 Coils shall be removable from the casing through the access panel after the connection package is disconnected, without cutting the casing.

9.2 Design Water Temperatures

9.2.1 The chilled water entering temperature shall be as indicated in the datasheet.
Chilled Water Entering Temperaturerange
°F
3665
Per drawings — design water temperatures as indicated on the fan-coil unit schedule (deferred by default)
9.2.2 The heating water entering temperature shall be as indicated in the datasheet.
Heating Water Entering Temperaturerange
°F
100200
Per drawings — design water temperatures as indicated on the fan-coil unit schedule (deferred by default)
9.2.3 The leaving water temperature and the water flow for each coil shall be as indicated on the fan-coil unit schedule.
9.2.4 Where a changeover 2-pipe service is selected, the single coil shall be selected at both the chilled water and the heating water temperatures indicated in the datasheet.
NOTE A wide water temperature difference across the coil lowers the flow the plant pumps and the pipe size that carries it, and it is the design basis on which low-flow plants and condensing heating plants depend. The same coil delivers less capacity at the wider difference, because the mean water temperature in the tubes moves toward the air temperature, so a wide difference is paid for in rows at the unit, and a unit selected at a narrow difference on a wide-difference plant starves the plant's return temperature and its own capacity together. (9.2.5)

9.3 Coil Freeze Protection

9.3.1 Requirements in this article apply where an outdoor air inlet collar is selected in the datasheet, or where a unit is installed in a space that can fall below 35 °F.
9.3.2 The unit shall be furnished with a low-temperature detection device located to sense the air entering the coil.
9.3.3 On detection of an entering air temperature below the setpoint stated in the sequence of operation, the control package shall stop the fan, close the outdoor air damper where a motorized damper is furnished, and open the heating water valve where a heating coil is served, and shall report the condition to the building automation system.
9.3.4 Where the Contract Documents direct that the system be charged with a glycol solution, the coil selection shall be stated at the glycol concentration indicated under Hydronic PipingHydronic PipingResolves to the current adopted revision.sync/hydronic-piping, and the capacity and pressure drop corrections for the solution shall appear in the coil selection data.
NOTE A coil with stagnant water in it freezes in minutes once the air crossing it is below freezing, and the first sign is water on the ceiling when the ice lets go. The low-temperature device is the backstop for the hours the unit is off and the damper has leaked, and the open heating valve keeps water moving through the coil that is most exposed; neither replaces a damper that closes and a wall opening that is sealed when the fan is off. (9.3.5)

10 Electric Heater

10.1 Heater Rating and Construction

10.1.1 Requirements in this section apply where a supplementary electric heater is selected in the datasheet.
10.1.2 The electric heater capacity shall be as indicated in the datasheet.
Electric Heater Capacityrange
kW
0.530
Per drawings — heater capacity as indicated on the fan-coil unit schedule (deferred by default)
10.1.3 The electric heater element construction shall be as indicated in the datasheet.
Electric Heater Element Constructionradio
● Open-coil nickel-chromium resistance wire on ceramic insulators
○ Sheathed tubular element
NOTE An open-coil element transfers heat directly from the wire to the air, responds fastest, and costs least, and it leaves the energized wire exposed to whatever the airstream carries. A sheathed element puts a metal barrier between the wire and the air, which tolerates a contaminated airstream and an airflow that is lower or less steady, at a higher cost and a slower thermal response. (10.1.4)
10.1.5 The electric heater capacity control shall be as indicated in the datasheet.
Electric Heater Capacity Controlradio
○ Single stage
○ Two stages
○ Modulating, by a silicon-controlled rectifier
NOTE A single-stage heater turns on at full capacity and off, so the discharge temperature steps by the full heater capacity divided by the airflow, and the zone cycles about its setpoint at an amplitude set by that step and the room's thermal mass. Two stages halve the step. A modulating heater removes the step and holds the discharge temperature the sequence asks for, at the cost of a power device that needs its own cooling and that generates electrical harmonics the branch circuit has to tolerate. The step matters most on a small room with a large heater and a low fan speed, which is the hotel room and the patient room. (10.1.6)
10.1.7 The heater shall be located downstream of the hydronic coil in the direction of airflow and shall be arranged so that the airstream passes over every element.

10.2 Heater Safety Devices

10.2.1 Every electric heater shall be furnished with a primary automatic-reset thermal cutout.
10.2.2 Every electric heater shall be furnished with a secondary manual-reset thermal cutout independent of the primary cutout.
10.2.3 Every electric heater shall be furnished with an airflow proving device that de-energizes the heater whenever airflow falls below the minimum airflow the manufacturer requires for heater operation.
10.2.4 The airflow proving interlock shall be wired in series with the heater control circuit so that a controller failure, a network failure, or a software error cannot energize the heater without airflow.
10.2.5 The manufacturer shall state the minimum airflow required for heater operation for each scheduled unit, and the lowest fan speed at which the heater is permitted to operate shall deliver not less than that airflow.
NOTE An electric heater energized without airflow raises the element to a temperature limited only by radiation and by the cutouts, and the cutout is a backstop rather than a control. Airflow proof is a hard interlock rather than a software permissive, and on a unit whose fan can be set to a low speed by an occupant it is the one safety that has to hold at every speed the occupant can select. (10.2.6)

11 Fan and Motor

11.1 Fan Wheel and Motor

11.1.1 The fan wheel type shall be as indicated in the datasheet.
Fan Wheel Typeradio
● Forward-curved centrifugal
○ Backward-curved centrifugal
NOTE A forward-curved wheel is compact, quiet at the low static pressures a fan-coil unit sees, and the wheel nearly every unit in the market carries. A backward-curved wheel is more efficient at higher static pressure and holds its airflow more steadily as the filter loads, which is why it appears on the larger blower coil units and on units ducted against higher resistance, at a larger casing and a higher cost. (11.1.2)
11.1.3 Fan wheels shall be statically and dynamically balanced and shall be mounted directly on the motor shaft or on a resilient fan deck so that fan vibration is not transmitted to the casing.
11.1.4 The fan motor type shall be as indicated in the datasheet.
Fan Motor Typeradio
● Electronically commutated motor
○ Permanent split capacitor motor
NOTE An electronically commutated motor holds a high efficiency across its speed range and accepts a speed command directly, so the airflow is set at commissioning by changing a signal or a programmed tap rather than by changing a winding, and it runs at a fraction of the input power of the alternative at every reduced speed. A permanent split capacitor motor is efficient near its design point and falls away sharply below it, its airflow is set in the discrete steps its winding taps provide, and it costs less at the unit. The energy code is the condition that usually decides it: where the code requires a fractional-horsepower fan motor to be electronically commutated or to meet an efficiency only that motor reaches, the alternative is no longer selectable. (11.1.5)
11.1.6 Fan motors shall comply with the fan motor efficiency provisions of Adopted Energy CodeAdopted Energy CodeParameterEach project supplies its own value.adopted-energy-code for fan-coil units and terminal equipment.
11.1.7 Fan motors shall be permanently lubricated, shall be furnished with integral thermal overload protection, and shall comply with the applicable provisions of NEMA MG 1.
11.1.8 The fan and motor assembly shall be removable through the access panel without disconnecting the coil connections, the condensate connection, or the duct connections.
11.1.9 The fan input power at the design operating point shall not exceed the value indicated in the datasheet.
Fan Input Power at the Design Operating Pointrange
Not more than
W/cfm
0.10.150.20.250.30.350.40.50.751
11.1.10 Where the datasheet does not indicate a fan input power limit, the manufacturer shall state the fan input power at the design operating point for each scheduled unit in the action submittal.
11.1.11 The fan input power stated for each unit shall be the total input power to the motor and its integral electronics at the scheduled airflow and external static pressure, derived from testing in accordance with ANSI/AMCA 210.
NOTE A fan-coil fan is a small load that runs for every occupied hour of every room in the building, so the fleet's input power is a continuous building load rather than an equipment rating. Power stated at the motor shaft, or at a static pressure lower than the installed unit will see, understates the quantity by a proportion that is largest on exactly these small motors. (11.1.12)

11.2 Fan Speed Control

11.2.1 The fan speed control means shall be as indicated in the datasheet.
Fan Speed Control Meansselect
Fixed speed set at the unit during startup
Multi-speed selected by the occupant at the zone sensor or the unit
Modulating speed commanded by the zone controller
NOTE A fixed speed is set once at startup and gives the occupant nothing to adjust, which suits a space where the airflow is a design quantity rather than a comfort preference. Multi-speed selection gives the occupant a fan switch, which is the expected interface in a hotel room or an apartment and is the setting that goes to low and stays there, so the sequence has to deliver the room's load at the speed the occupant leaves it on. A modulating speed under the controller tracks the load continuously, holds the quietest speed the load allows, and removes the fan switch from the occupant's hands, at the cost of a controller output and a sequence that has to be written and commissioned. (11.2.2)
11.2.3 The speed control means available to a unit is constrained by the motor selected: a permanent split capacitor motor accepts only the discrete speeds its winding taps provide, while an electronically commutated motor accepts a continuous speed command, and the two selections shall be made together.
11.2.4 Where multi-speed selection is selected, the unit shall provide not fewer than three fan speeds.
11.2.5 Where a modulating speed is selected, the controller shall not command a speed below the lowest speed at which the electric heater, where furnished, is permitted to operate while the heater is energized.
11.2.6 The as-commissioned fan speed setting for each unit shall be recorded in the field startup and verification record.

11.3 Electrical Characteristics

11.3.1 The unit supply voltage shall be as indicated in the datasheet.
Unit Supply Voltagerange
V
115120208230240277460480
Per drawings — electrical drawings and panel schedules (deferred by default)
11.3.2 The unit supply phase shall be as indicated in the datasheet.
Unit Supply Phaseradio
○ Single phase, 1Φ
○ Three phase, 3Φ
Per drawings — electrical drawings and panel schedules (deferred by default)
11.3.3 The electrical characteristics shown on the fan-coil unit schedule and those shown on the electrical documents shall be reconciled before any unit is released for fabrication, and any discrepancy shall be resolved by the Engineer of Record.
11.3.4 The unit nameplate shall state the minimum circuit ampacity and the maximum overcurrent protective device rating for the unit as furnished, including the electric heater where one is furnished.

12 Filters

12.1 Filter Efficiency and Media

12.1.1 Each unit shall be furnished with a filter located so that all air entering the coil, including ventilation air admitted through a connection on the unit, passes through it.
12.1.2 The filter efficiency shall be as indicated in the datasheet, rated in accordance with ANSI/ASHRAE 52.2.
Filter Efficiencyrange
Not less than
MERV
146810111314
12.1.3 The filter media type shall be as indicated in the datasheet.
Filter Media Typeselect
Disposable fiberglass panel
Disposable pleated media
Cleanable permanent media
NOTE A fiberglass panel protects the coil from lint and little else, costs the least, and is the filter the unit ships with when nothing is specified. A pleated filter reaches the efficiency the ventilation standard asks for upstream of a wetted coil and holds more dust before it loads, at a higher resistance the fan has to overcome, which on a unit with a small fan and a one-inch slot can be the difference between the scheduled airflow and a fraction of it. A cleanable filter is washed rather than replaced, which suits an owner with the staff to wash it and a space where a dirty filter would otherwise sit for years, and it protects the coil less at any rating than the disposable media. The condition that fixes the floor is the ventilation standard's requirement for a minimum efficiency upstream of a cooling coil; the condition that fixes the ceiling is the fan. (12.1.4)
12.1.5 The filter depth shall be as indicated in the datasheet.
Filter Depthrange
in.
124
12.1.7 Filters shall be of a standard nominal size available from more than one filter manufacturer, and the size shall be stated on the unit label and in the operation and maintenance manual.

12.2 Filter Access

12.2.1 The filter access arrangement shall be as indicated in the datasheet.
Filter Access Arrangementselect
Through the return grille of an exposed or recessed unit
Slide-out track through a side or bottom access panel of a concealed unit
At a filter grille in the ducted return, with no filter in the unit
NOTE Access through the return grille puts the filter where the occupant or the housekeeper can reach it without a ladder, which is why it is the arrangement of the console unit and the recessed unit. A slide-out track on a concealed unit needs a ceiling opening in line with the track and a clear path the full length of the filter, which is the coordination item most often lost to a sprinkler main or a conduit. A filter grille in the return duct moves the filter to the ceiling where it can be changed from the room, leaves the unit without a filter of its own, and depends on the return duct being sealed so that no unfiltered plenum air reaches the coil. (12.2.2)
12.2.3 The filter shall be replaceable without removing the unit from its mounting, without disconnecting any piping, duct, or wiring, and without tools other than those needed to open the access panel.
12.2.4 Where a filter grille in the ducted return is selected, the return duct between the grille and the unit shall be sealed to the duct seal class established in HVAC DuctworkHVAC DuctworkResolves to the current adopted revision.sync/hvac-ductwork so that no unfiltered air enters the coil.
12.2.5 The filter access location for each concealed unit shall be shown on the shop drawings together with the clear path required to withdraw the filter.

13 Drain Pan and Condensate

13.1 Primary Drain Pan

13.1.1 Each unit with a cooling coil shall be furnished with a primary drain pan beneath the full length and width of the coil and beneath the coil headers, return bends, and the coil connections within the casing.
13.1.2 The primary drain pan material shall be as indicated in the datasheet.
Primary Drain Pan Materialselect
Type 304 stainless steel to ASTM A240
Galvanized steel with a factory-applied corrosion-resistant coating
Molded polymer
NOTE A drain pan ages under a continuous condensate film for the cooling life of the unit, and the material choice is about how it ages. A coated steel pan serves until the coating is scratched, which a filter change or a coil cleaning can do, and then rusts from the scratch. A polymer pan cannot corrode and can crack under a coil that is dropped onto it or a fastener that is overdriven. A stainless pan costs more and does neither, which is why it is the pan the market specifies wherever the unit is above a finished ceiling it cannot be allowed to stain. (13.1.3)
13.1.4 The primary drain pan shall be sloped in two planes to the drain connection so that it holds no standing water when the fan is off.
13.1.5 The primary drain pan shall be insulated on the underside or constructed double-wall so that the pan exterior does not sweat at the scheduled entering air conditions.
13.1.6 The primary drain pan shall be furnished with a drain connection not smaller than 3/4 in. at its low point, extended beyond the casing for a field connection.
13.1.7 The primary drain pan shall be removable or accessible for cleaning through the access panel without removing the coil.
NOTE A pan that holds water between cooling cycles is a warm, dark reservoir in the supply airstream, which is the growth condition the ventilation standard's wetted-surface provisions exist to prevent. Every geometric requirement on the pan is there to make it empty rather than merely drain. (13.1.8)

13.2 Condensate Overflow Protection

13.2.1 The condensate overflow protection method shall be as indicated in the datasheet.
Condensate Overflow Protection Methodselect
Water-level detection device in the primary drain pan that stops the cooling source
Auxiliary drain pan beneath the unit with a water-level detection device that stops the cooling source
Auxiliary drain pan beneath the unit with a separate drain to a conspicuous location
Separate overflow drain line from the primary drain pan to a conspicuous location
NOTE A detection device in the primary pan is the least hardware, stops the condensate at its source, and depends on a switch that is wired and tested; it is the arrangement a concealed unit above a ceiling almost always carries. An auxiliary pan under the whole unit catches a leak from the casing, the coil connection, or a sweating valve package as well as an overflow from the pan, and it needs the depth below the unit to fit. A separate drain or overflow line to a conspicuous location tells someone the unit has overflowed without stopping it, which suits a building with staff who will see it and a unit whose cooling cannot be allowed to shut off on a nuisance trip. The adopted mechanical code sets which arrangements satisfy it where an overflow would damage the building, and the selection is made within that set. (13.2.2)
13.2.3 Overflow protection shall comply with the condensate overflow provisions of Adopted Mechanical CodeAdopted Mechanical CodeParameterEach project supplies its own value.adopted-mechanical-code.
13.2.4 Overflow protection shall not be omitted on any unit installed above a finished ceiling or above any space whose contents an overflow would damage.
13.2.5 Where a water-level detection device is selected, it shall stop the cooling source by closing the chilled water valve, by stopping the fan, or both, and shall report the condition to the building automation system.
13.2.6 Where a water-level detection device is selected, the device shall comply with HVAC Controls InstrumentationHVAC Instrumentation and Control DevicesResolves to the current adopted revision.sync/hvac-controls-instrumentation whichever party furnishes it, and the party that mounts and wires it shall be as indicated for the control package in this standard.
13.2.7 Where an auxiliary drain pan is selected, it shall extend not less than 3 in. beyond the casing on every side, shall be constructed of the material selected for the primary drain pan, and shall be supported independently of the unit.
13.2.8 Where the parties disagree whether an overflow at a unit would damage the building, the Engineer of Record shall make the initial determination.

13.3 Condensate Removal

13.3.1 The condensate removal from the primary drain pan shall be as indicated in the datasheet.
Condensate Removalradio
● Gravity drain from the pan connection
○ Condensate pump furnished within the unit, with an integral high-level switch
NOTE A gravity drain has no moving parts and fails only by blockage, and it needs a continuous fall from the pan connection to the point of disposal, which a unit set tight to the slab above or a riser far from the room cannot always provide. An integral pump lifts the condensate to a drain the geometry allows and adds a motor, a float, and a reservoir to every unit that has one, each of which is a maintenance item and a failure point above a finished ceiling. (13.3.2)
13.3.3 Where an integral condensate pump is selected, its high-level switch shall stop the cooling source in the same manner as the overflow protection device and shall report to the building automation system.
13.3.4 Where an integral condensate pump is selected, the pump shall be accessible for service through the access panel and shall be removable without draining the pan.
13.3.5 The condensate trap and the drain piping from the pan connection to the point of disposal shall be furnished under Condensate Drainage PipingHVAC Condensate Drainage PipingResolves to the current adopted revision.sync/condensate-drainage-piping, and the manufacturer shall state the pan static pressure the trap is to be sized for in the action submittal.

14 Casing and Cabinet

14.1 Casing Construction and Liner

14.1.1 Casings shall be fabricated of galvanized steel sheet to ASTM A653 not lighter than 20 gauge for the structural members and not lighter than 22 gauge for the panels, with the panel stiffness required to prevent drumming at the design fan speed.
14.1.2 Casings shall be furnished with integral mounting brackets, hanger lugs, or threaded inserts sized for the operating weight of the unit, and the Contractor shall not penetrate the casing to attach a hanger.
14.1.3 Each unit shall be furnished with a removable access panel giving service access to the fan and motor, the coil, the drain pan, the filter, the electric heater where furnished, and the control enclosure.
14.1.4 The casing liner type shall be as indicated in the datasheet.
Casing Liner Typeselect
Fibrous glass liner to ASTM C1071 with a coated or foil-faced airstream surface
Closed-cell elastomeric foam liner with no exposed fiber
Double-wall construction with fibrous glass encapsulated between solid metal skins
Unlined casing
NOTE The liner is the unit's thermal insulation and its only broadband sound absorber, and it works on the fan noise generated inches from it. A faced fibrous glass liner is the construction nearly every unit carries, and it depends on its facing to keep fiber out of the airstream. A closed-cell foam liner or a double-wall casing carries no exposed fiber, which is what a healthcare infection control assessment or a cleanable-surface requirement asks for, at a higher cost and, for the foam, a thinner section with less sound absorption. An unlined casing sweats on the outside in cooling and transmits the fan noise undamped, and it is selectable for a unit whose casing is insulated and attenuated by other means. (14.1.5)
14.1.6 Unless the datasheet selects an unlined casing, the casing shall be lined on every surface in contact with the conditioned airstream, including the drain pan underside where the pan is not double-wall.
14.1.7 Liner materials and adhesives shall have a flame spread index not greater than 25 and a smoke developed index not greater than 50 when tested to ASTM E84.
14.1.8 Fibrous glass liner shall show no fungal growth when tested to ASTM C1338.
14.1.9 Liner airstream surfaces shall be faced, coated, or encapsulated so that no fiber erodes into the airstream at the highest face velocity the unit is cataloged for.
14.1.10 Liner shall be secured mechanically as well as adhesively at every edge exposed to the airstream, and every cut edge shall be sealed.

14.2 Exposed Cabinet Finish and Grilles

14.2.1 Requirements in this article apply where an exposed or a recessed cabinet enclosure is selected in the datasheet.
14.2.2 The exposed cabinet finish shall be as indicated in the datasheet.
Exposed Cabinet Finishselect
Factory-applied powder coat or baked enamel in a stock color
Factory-applied powder coat or baked enamel in a custom color matched to a sample
Factory-primed for field painting
NOTE A stock color ships from the line with no lead-time or cost premium and is the finish the hospitality and multifamily markets take by default, in a small palette of neutral tones. A custom color matches the room's finish schedule at a color-match charge and a longer lead time, and it is what an architect asks for where the cabinet is a visible element of the room. A primed cabinet is painted in the field with the wall, which matches the wall exactly and depends on the painter protecting the grilles and the controls from the paint. (14.2.3)
14.2.4 Factory-applied finishes shall withstand a salt spray exposure to ASTM B117 for not less than 500 hours without blistering or creep from a scribe, and the finish system shall be stated in the submittal.
14.2.5 Finish color shall be as indicated on the room finish schedule.
14.2.6 The discharge grille type shall be as indicated in the datasheet.
Discharge Grille Typeradio
● Stamped steel louvered grille integral to the cabinet
○ Extruded aluminum double-deflection grille with adjustable blades
NOTE A stamped grille is part of the cabinet panel and throws the air in the fixed direction it was stamped for. A double-deflection grille lets the balancer and the occupant set the throw, which is what a console under a window with a drape, or a unit discharging toward a bed, needs to avoid a draft on the occupant. (14.2.7)
14.2.8 Exposed cabinet units shall be furnished with a return grille sized so that the face velocity at the design airflow does not exceed 500 ft/min.
14.2.9 Where an exposed cabinet unit is accessible to the public, the front panel and the grilles shall be secured with tamper-resistant fasteners or a keyed latch.

14.3 Stacked Riser Construction

14.3.1 Requirements in this article apply where a stacked unit with integral risers is selected in the datasheet.
14.3.2 The riser pipe material shall be as indicated in the datasheet.
Riser Pipe Materialradio
● Type L copper water tube to ASTM B88
○ Type M copper water tube to ASTM B88
○ Schedule 40 steel pipe
NOTE A copper riser is joined at each floor with a soldered or brazed coupling at the unit, and the heavier Type L wall carries the pressure of a tall building's static head with margin where the lighter Type M wall is at its rating. A steel riser is heavier, is threaded or welded at the unit, and resists the erosion that a high-velocity copper riser suffers at the fittings, which is why it appears on the tallest buildings and on the largest units. (14.3.3)
14.3.4 Riser sizes shall be as indicated on the hydronic riser diagram.
14.3.5 Risers shall be furnished with a swaged, flexible, or coupled joint at each floor that accommodates the misalignment and the thermal and structural movement between floors stated in the riser data submittal.
14.3.6 Risers shall extend through the casing top and bottom to a joint location that is accessible for making the joint and for inspecting it before the floor penetration is firestopped.
14.3.7 The riser insulation application shall be as indicated in the datasheet.
Riser Insulation Applicationradio
○ Factory-applied within the casing
○ Field-applied under the mechanical insulation scope
NOTE Factory-applied insulation arrives on the riser and leaves only the floor joint to be insulated in the field, which is faster and is protected by the casing from the damage a field-insulated riser suffers while the floor above is still under construction. Field-applied insulation is specified and inspected under the insulation standard with the rest of the building's piping, which keeps one standard and one trade responsible for the vapor retarder on every cold pipe, and it exposes the riser inside the casing to the insulator's reach. (14.3.8)
14.3.9 Riser insulation, whichever party applies it, shall be continuous through the floor joint and shall carry a vapor retarder on the chilled water and condensate risers that is sealed at every joint in accordance with Mechanical InsulationMechanical InsulationResolves to the current adopted revision.sync/mechanical-insulation.
14.3.10 Each stacked unit shall be furnished with isolation valves on the branch from each riser to the coil so that the coil and its connection package can be isolated from the riser without draining the riser.
14.3.11 Riser expansion compensation, anchorage, and guides shall be designed by the unit manufacturer for the riser height of the project and shall be stated in the riser data submittal.
14.3.12 The floor penetration firestop at each riser shall be furnished under FirestoppingFirestoppingResolves to the current adopted revision.sync/firestopping for the riser material and the insulation selected.
14.3.13 Risers shall be pressure tested with the piping system in accordance with Hydronic PipingHydronic PipingResolves to the current adopted revision.sync/hydronic-piping before the casings are closed and the floors are finished.

15 Sound Performance

15.1 Sound Rating Basis

15.1.1 Sound power of each scheduled unit shall be rated under the program indicated in the datasheet.
Sound Rating Programradio
○ AHRI 350
○ AHRI 260
Derived — the cabinet enclosure selected, with a unit discharging to the room through its own grilles rated under AHRI 350 and a ducted unit rated under AHRI 260 (by default)
15.1.2 Sound power shall be reported in octave bands 2 through 7 at the scheduled fan speed and the scheduled external static pressure, with discharge, inlet, and radiated sound reported separately for a ducted unit.
15.1.3 Occupied-space sound levels shall be estimated from the reported sound power in accordance with ANSI/AHRI 885, and the submittal shall state the room absorption, the unit-to-listener distance, and the ceiling and plenum attenuation values used.
NOTE A unit discharging into the room through its own grille is rated as a whole, because the occupant hears everything it makes. A ducted unit is rated by path, because the duct, the lining, and the outlet attenuate the discharge sound while the radiated sound reaches the occupant through the ceiling with almost nothing in the way, and on a unit above a lay-in ceiling the radiated path is the one that sets the room level. (15.1.4)

15.2 Occupied-Space Sound Limit

15.2.1 The maximum sound level in the occupied space attributable to the unit, with the fan at the scheduled design speed, shall be as indicated in the datasheet.
Occupied-Space Sound Level at the Design Fan Speedrange
Not more than
NC
152025303540455055
NOTE Sound criteria vary by how the space is used, and the ranges commonly applied are: (15.2.2)
  • NC 25 to NC 30 for hotel guest rooms, patient rooms, residences, and executive offices
  • NC 30 to NC 35 for private offices, classrooms, conference rooms, and libraries
  • NC 35 to NC 40 for open offices, retail sales areas, restaurants, and lobbies
  • NC 40 to NC 45 for corridors, public circulation, and light industrial spaces
  • NC 45 to NC 50 for kitchens, locker rooms, and mechanical and service areas
15.2.3 Where the Contract Documents indicate a lower sound limit for a specific space, that limit shall govern in that space.
15.2.4 The unit selection submitted for each scheduled zone shall demonstrate compliance with the applicable limit using the actual room volume, room absorption, and unit-to-listener distance for that zone.
15.2.5 Where a multi-speed or modulating fan is furnished, the sound level at the highest speed the occupant or the controller can select shall also be stated in the submittal.
NOTE A fan-coil unit sits in the room it serves or just above it, so there is no duct run to attenuate it and no distance to lose it over; the fan speed selected for capacity is the sound the occupant lives with, and a unit selected to meet its capacity at high speed and its sound criterion at low speed meets neither in the room. (15.2.6)
15.2.7 Sound criteria expressed as noise criteria values shall be evaluated by the tangent method of ANSI/ASA S12.2 where field measurement is performed.

16 Zone Control and Control Package

16.1 Zone Control Type and Mounting

16.1.1 The zone control type shall be as indicated in the datasheet.
Zone Control Typeselect
Networked direct digital controller reporting to the building automation system
Standalone direct digital controller with no network connection
Thermostat with a fan speed selector and no controller
16.1.3 The controller, where furnished, the sequences of operation, the network, and the points shall comply with Building Automation SystemBuilding Automation SystemResolves to the current adopted revision.sync/building-automation-system.
16.1.4 The thermostat, the zone sensor, the control valves, the valve actuators, the changeover sensor, the low-temperature detection device, and the water-level detection device shall comply with HVAC Controls InstrumentationHVAC Instrumentation and Control DevicesResolves to the current adopted revision.sync/hvac-controls-instrumentation whichever party furnishes them.
16.1.5 The control device mounting and wiring responsibility shall be as indicated in the datasheet.
Control Device Mounting and Wiring Responsibilityselect
Control devices furnished, mounted, and wired to a terminal strip by the unit manufacturer
Control devices furnished by the controls contractor, shipped to the unit manufacturer for factory mounting and wiring
Control devices furnished by the unit manufacturer and shipped loose for field mounting and wiring
Control devices furnished, mounted, and wired by the controls contractor in the field
NOTE Who furnishes the controller and the valve actuators, who mounts them, and who wires them are separate commercial decisions, and the units arrive in whichever state the decision leaves them. Factory mounting and wiring puts the devices on the unit before it ships, with the wiring diagram and the terminal strip tested at the factory, and removes a field operation from every unit on the project; it ties the controls contractor to the manufacturer's device selection or to a shipment of devices to the factory. Field mounting keeps the controls contractor in charge of every device and every wire, which keeps the sequence, the graphics, and the warranty in one party's hands, and it puts a technician in every ceiling on the project. The failure to avoid is leaving any one of the three unassigned, because the gap surfaces at startup when the schedule has no room for it. (16.1.6)
16.1.7 Where devices are factory-mounted and wired, the unit shall be furnished with a terminal strip in the control enclosure to which every factory-wired device is landed and labeled, and the field connections shall be limited to power, the zone sensor, and the network.
16.1.8 Where devices are furnished by one party and mounted by another, the furnishing party shall deliver the devices to the mounting party with the mounting hardware and the wiring diagram, and the mounting party shall be responsible for the correctness of the mounting and the wiring.
16.1.9 The zone sensor location shall be as indicated in the datasheet.
Zone Sensor Locationradio
● Wall-mounted in the zone
○ Unit-mounted on the cabinet of an exposed unit
NOTE A wall-mounted sensor reads the room where the occupant is and is wired or networked back to the unit. A unit-mounted sensor on a console cabinet needs no wall wiring and reads the air at the cabinet, which is the room's air only when the discharge is not short-circuiting to the return, and it is the arrangement that makes a console a self-contained product. (16.1.10)

16.2 Control Valve and Coil Connection Package

16.2.1 The control valve operation shall be as indicated in the datasheet.
Control Valve Operationradio
○ Two-position, open or closed on a call from the zone
○ Modulating, positioned by the zone controller
NOTE A two-position valve is the least cost and the least to commission, and it is the valve a thermostat without a controller can drive; the zone cycles between full coil capacity and none, and on a 2-pipe coil with a wide water temperature difference the cycle is felt at the discharge grille. A modulating valve holds the coil at the capacity the load needs, keeps the water temperature difference where the plant was designed for it, and needs a controller output and an actuator that costs more than the two-position one. (16.2.2)
16.2.3 The coil control and balancing arrangement shall be as indicated in the datasheet.
Coil Control and Balancing Arrangementselect
Two-way control valve with a manual calibrated balancing valve
Two-way control valve with an automatic flow-limiting valve
Three-way control valve with a balancing valve on the bypass
Pressure-independent control valve combining control and flow limiting
NOTE A two-way valve shuts the coil off and lets the distribution reduce its flow at part load, which is what a variable-flow plant is built around; with a manual balancing valve the flow is set once by the balancer and drifts as other zones open and close, and with an automatic flow limiter it is capped at the unit regardless of what the rest of the system does. A three-way valve passes the coil's flow through a bypass when the coil is closed, so the distribution flow is constant, which suits a constant-flow plant and defeats the pump energy saving a variable-flow plant exists for. A pressure-independent valve controls and limits flow in one body, holds the commanded flow as the differential pressure across it changes, and needs no separate balancing device, at a higher cost per unit and a sizing that has to match the coil's scheduled flow. (16.2.4)
16.2.5 Where a three-way control valve is selected on a plant with variable-flow distribution, the Engineer of Record shall document the constant-flow bypass the plant has been designed to accept.
16.2.6 Each coil shall be served by an isolation valve on the supply and on the return, a strainer upstream of the control valve, the control and balancing arrangement indicated in the datasheet, and a drain connection on the coil side of the isolation valves.
16.2.7 The coil connection package furnishing shall be as indicated in the datasheet.
Coil Connection Package Furnishingselect
Factory-assembled and factory-mounted on the unit by the unit manufacturer
Factory-assembled by the unit manufacturer and shipped loose for field mounting
Field-assembled from components furnished under the hydronic specialties and controls standards
NOTE A factory-mounted package arrives sized for the coil, leak tested with it, and fitted inside the casing, so the piping contractor makes two connections per coil and the unit has one party responsible for everything inside the casing; it fixes the package to the manufacturer's component selection. A package shipped loose keeps the manufacturer's sizing and leaves the mounting to the field, which suits a unit whose connection hand or clearance is not settled at order. A field-assembled package is specified device by device under the specialties and controls standards, which gives the engineer every component choice and gives the field every joint, and it is the arrangement on a project whose specialties are standardized across equipment of many kinds. (16.2.8)
16.2.9 The additional components furnished in the coil connection package shall be as indicated in the datasheet.
Coil Connection Package Componentscheckbox
☐ Flexible hose connectors between the package and the coil
☑ Pressure and temperature test ports on the supply and the return
☑ Unions or hose-end connections permitting coil removal
☑ Manual air vent at the package high point
☑ Hose-end drain valve at the package low point
☐ Strainer blowdown valve
16.2.10 Balancing valves, automatic flow-limiting valves, pressure-independent control valves, strainers, flexible connectors, test ports, and the other hydronic specialties in the package shall comply with Hydronic SpecialtiesHydronic SpecialtiesResolves to the current adopted revision.sync/hydronic-specialties whichever party furnishes them.
16.2.11 Isolation valves in the package shall comply with HVAC Piping ValvesGeneral-Duty Valves for HVAC PipingResolves to the current adopted revision.sync/hvac-piping-valves whichever party furnishes them.
16.2.12 Two-way and three-way control valves and their actuators in the package shall comply with HVAC Controls InstrumentationHVAC Instrumentation and Control DevicesResolves to the current adopted revision.sync/hvac-controls-instrumentation whichever party furnishes them.
16.2.13 Where the package is factory-assembled, the manufacturer shall state the flow setting of each balancing or flow-limiting device, the valve flow coefficient, and the close-off rating in the coil connection package data.
16.2.14 Every package shall be arranged so that the coil can be removed after the isolation valves are closed without dismantling the piping beyond them.
16.2.15 The chilled water package and its connections within the casing shall be insulated with a vapor-sealed insulation, or shall be located over the primary drain pan, so that condensation from them does not reach the ceiling.

17 Electrical Provisions

17.1 Disconnecting Means

17.1.1 The disconnecting means for each unit shall be as indicated in the datasheet.
Unit Disconnecting Meansselect
Factory-mounted disconnect switch on the unit
Field-installed disconnect switch within sight of the unit
Lockable circuit breaker at the branch panelboard
NOTE A factory-mounted switch arrives on the unit, in the control enclosure, with no field box to mount above the ceiling, and it adds a listed component to every unit. A field-installed switch is the electrician's standard device in the electrician's standard box, placed where the ceiling access is, and it is one more item to coordinate at every unit. A lockable breaker at the panel satisfies the code where the panel is within the conditions the code allows and leaves nothing at the unit, which suits a hotel floor with a panel in the corridor and a unit in every room, and it means the technician walks to the panel to make the unit safe. (17.1.2)
17.1.3 The disconnecting means shall comply with NFPA 70, and where a lockable breaker at the branch panelboard is selected, the panelboard shall be permanently labeled with the unit tags it serves.
17.1.4 Where an electric heater is furnished, the disconnecting means shall disconnect the heater and the fan together unless separate circuits are selected.

17.2 Power Connection

17.2.1 The power connection arrangement shall be as indicated in the datasheet.
Power Connection Arrangementradio
● Single-point connection serving the fan, the heater where furnished, and the controls
○ Separate connections for the fan and for the electric heater
NOTE A single-point connection is one circuit and one disconnect at every unit, with the heater and the fan protected together inside the unit. Separate connections let a heater on a three-phase circuit share a unit with a fan on a single-phase circuit, or let the heater be metered and switched apart from the fan, at the cost of a second circuit and a second disconnect at every unit that has them. (17.2.2)
17.2.3 Each unit shall be served by a branch circuit sized for the minimum circuit ampacity and protected at not more than the maximum overcurrent protective device rating on the unit nameplate.
17.2.4 Where a single-point connection is selected and an electric heater is furnished, the unit shall be furnished with the internal overcurrent protection the listing requires for the heater and the fan on one circuit.
17.2.5 A control power transformer, where the control devices operate at a voltage other than the unit supply voltage, shall be furnished within the unit.

18 Factory Testing

18.1 Each unit shall be subjected to the manufacturer's production test program before shipment, and the following shall be included in that program:
  • Leak test of each hydronic coil and, for a stacked unit, each riser at the specified test pressure
  • Operation of the fan at each available speed, verifying rotation, current, and freedom from rubbing
  • Electrical functional test of the heater section where furnished, verifying the airflow proving interlock, the primary cutout, and the secondary cutout
  • Drain pan drainage check with water introduced at the far end of the pan
  • Point-by-point test of every factory-wired control device against the wiring diagram where devices are factory-mounted and wired
18.2 No unit shall ship until every test in the production test program has passed, and a unit that fails a test shall be corrected and retested at the manufacturer's expense.
18.3 The factory test witnessing requirement shall be as indicated in the datasheet.
Factory Test Witnessingradio
● Production test program with certified reports and no witness
○ Witnessed test on a sample of units of each configuration
○ Witnessed test on every unit furnished
NOTE A fan-coil unit is a production item made in quantity, and the certified production test is what the market relies on. A witnessed test is bought for a configuration the project depends on and the manufacturer has not made before, such as a stacked unit with a riser arrangement engineered for the building, where seeing one unit tested is worth the trip. (18.4)
18.5 Where a witnessed test is required, the Contractor shall give the Engineer of Record not less than ten working days notice of the test date.
18.6 Where a witnessed test is required and the units are not ready on the scheduled date, the Contractor shall bear the cost of the Engineer of Record's return visit.

19 Delivery, Storage, and Handling

19.1 Units shall be delivered in the manufacturer's packaging with each unit marked with its project tag, with the coil connections capped, and with the discharge, return, and condensate openings sealed against construction dust.
19.2 Units shall be stored indoors in a clean, dry, weather-protected space until installation.
19.3 Units shall not be stored on bare ground or bare slab, in standing water, or in a space subject to freezing or to water intrusion.
19.4 Stacked units shall be stored upright, shall be supported on their bases, and shall not be stacked in storage beyond the height the manufacturer publishes.
19.5 Where a hydronic coil or a riser is exposed to a storage temperature below 35 °F, it shall be drained, blown clear with compressed air, and tagged as drained, and a corresponding entry shall be made on the unit schedule so that the coil is refilled and vented before startup.
19.6 Where the ceiling or the chase is not ready to receive units, the Contractor shall hold the units in protected storage rather than installing them and covering the openings.

20 Installation

20.1 Coordination and Service Access

20.1.1 Before ceiling suspension is installed, before ductwork is fabricated, and before risers are set, the Contractor shall verify that each unit can be installed with the service clearance the manufacturer publishes and that its access panel and filter are reachable from the room or from below the finished ceiling.
20.1.2 Service access shall be provided to the fan and motor, the coil and its connection package, the drain pan and its connection, the filter, the electric heater where furnished, and the control enclosure.
20.1.3 Where the ceiling construction below a concealed unit does not permit access through the ceiling itself, an access panel shall be coordinated with the finish schedule and installed below the unit access panel and the filter track.
20.1.4 Where a conflict cannot be resolved without relocating a unit from its scheduled position, the Contractor shall obtain the Engineer of Record's acceptance of the revised position, including the effect on the condensate drain slope and the riser alignment, before installing it.

20.2 Support and Isolation

20.2.1 Horizontal units shall be suspended from the building structure by threaded rod or trapeze hanger attached to the mounting provisions furnished on the casing, at not fewer than four points, in accordance with Hangers And SupportsHangers and Supports for Mechanical Piping and EquipmentResolves to the current adopted revision.sync/hangers-and-supports.
20.2.2 Units shall not be supported by the ceiling suspension system, by connected ductwork, or by connected piping.
20.2.3 Vertical and stacked units shall be set plumb on a level base and anchored to the floor or the wall at the points the manufacturer designates.
20.2.4 Units shall be installed level in the direction the manufacturer requires for the drain pan to empty completely, and the pan slope shall be verified with water before the ceiling is closed.
NOTE A unit hung out of level so that the pan does not drain is the recurring origin of standing water, odor, and the overflow that a float switch then reports as a nuisance trip. Checking the pan with water while the ceiling is open is the cheapest test in the standard, and the one that is skipped most. (20.2.5)
20.2.6 The hanger isolation for suspended units shall be as indicated in the datasheet.
Hanger Isolation for Suspended Unitsradio
○ Rigid hangers with no isolation
○ Neoprene hanger isolators
○ Spring hanger isolators
NOTE A fan-coil fan is small and runs at a low speed, and on a unit hung from a concrete slab with its fan on a resilient deck the structure rarely transmits anything audible, which is why rigid hangers are the arrangement most units carry. A neoprene isolator stops the high-frequency fan hum a light steel or wood structure would otherwise carry into the room above, at little cost. A spring isolator addresses the low-frequency vibration of a large blower coil unit and is more than the small unit needs. (20.2.7)
20.2.8 Isolators shall be selected and installed in accordance with Vibration Isolation And Seismic RestraintVibration Isolation and Seismic RestraintResolves to the current adopted revision.sync/vibration-isolation-and-seismic-restraint.
20.2.9 Seismic restraint of the unit shall be as indicated in the datasheet.
Seismic Restraintradio
○ Engineered seismic restraint of the unit to the structure
○ No seismic restraint beyond the manufacturer's attachment hardware
Derived — Seismic Design CategorySeismic Design CategoryParameterEach project supplies its own value.seismic-design-category applied to the unit weight, the component importance factor assigned to the unit, and the attachment height in accordance with ASCE 7 Chapter 13 (by default)
20.2.10 Where engineered restraint is furnished, it shall be designed, furnished, and installed in accordance with Vibration Isolation And Seismic RestraintVibration Isolation and Seismic RestraintResolves to the current adopted revision.sync/vibration-isolation-and-seismic-restraint, and restraints on an isolated unit shall engage only under seismic displacement.

20.3 Hydronic Connections

20.3.1 Chilled water and heating water piping from the plant to the coil connection package shall comply with Hydronic PipingHydronic PipingResolves to the current adopted revision.sync/hydronic-piping.
20.3.2 Piping at the unit shall be supported independently of the unit so that no piping load is carried by the casing, the coil connections, or the connection package.
20.3.3 Piping and the connection package shall be arranged so that the coil can be removed without dismantling the piping beyond the isolation valves.
20.3.4 Chilled water piping, the connection package, and the condensate connection within a ceiling plenum or a finished space shall be insulated continuously with a vapor retarder in accordance with Mechanical InsulationMechanical InsulationResolves to the current adopted revision.sync/mechanical-insulation, and the insulation shall not be interrupted at the unit connection.
20.3.5 Flexible hose connectors, where furnished, shall be installed without twist and with the bend radius the hose manufacturer publishes, and shall not be used to correct a piping misalignment.
20.3.6 Coils shall be filled, vented at the coil vent, and pressure tested with the piping system in accordance with Hydronic PipingHydronic PipingResolves to the current adopted revision.sync/hydronic-piping before the ceiling is closed.

20.4 Condensate Connections

20.4.1 The condensate drain from the pan connection shall be trapped, sloped, and routed to the point of disposal in accordance with Condensate Drainage PipingHVAC Condensate Drainage PipingResolves to the current adopted revision.sync/condensate-drainage-piping.
20.4.2 The trap shall be sized for the pan static pressure the manufacturer states in the action submittal.
20.4.3 Where an auxiliary drain pan or a separate overflow drain is selected, its drain shall terminate at a conspicuous location in accordance with Condensate Drainage PipingHVAC Condensate Drainage PipingResolves to the current adopted revision.sync/condensate-drainage-piping.
20.4.4 The water-level detection device, where furnished, shall be installed at the height and in the location the device manufacturer requires, and its operation shall be verified with water before the ceiling is closed.

20.5 Duct Connections

20.5.1 Requirements in this article apply where a concealed unit is ducted at the discharge, the return, or the ventilation air connection.
20.5.2 Ductwork at the unit shall be connected to the unit collars with a flexible connector that isolates the duct from the casing, and shall be sealed to the duct seal class established in HVAC DuctworkHVAC DuctworkResolves to the current adopted revision.sync/hvac-ductwork.
20.5.3 The discharge duct shall be sized and routed so that the external static pressure at the scheduled airflow does not exceed the value indicated in the datasheet for that unit, and the Contractor shall report any duct routing that cannot meet that value to the Engineer of Record before fabrication.
20.5.4 Diffusers, grilles, and registers served by a ducted unit shall be furnished and installed under HVAC Air Distribution DevicesHVAC Air Distribution DevicesResolves to the current adopted revision.sync/hvac-air-distribution-devices.
20.5.5 Where a ducted return is furnished, the return duct shall be sealed so that the unit draws from the room rather than from the plenum, except where the design draws return air from the plenum through a ceiling return grille.

20.6 Electrical and Control Wiring

20.6.1 Branch circuit conductors, the disconnecting means, and the connection to the unit shall comply with NFPA 70.
20.6.2 Control wiring between the unit terminal strip, the zone sensor, the thermostat, and the network shall be Class 2 cable installed in accordance with NFPA 70, and cable installed in a ceiling plenum shall be listed for that use.
20.6.3 Control wiring shall be routed and supported separately from line-voltage wiring and shall not be laid on ceiling tile, on pipe insulation, or on the unit casing.
20.6.4 Network wiring, addressing, and termination at the unit controller shall comply with Building Automation SystemBuilding Automation SystemResolves to the current adopted revision.sync/building-automation-system.

20.7 Pre-Startup Inspection

20.7.1 Before the units are energized and the systems are started, the Contractor shall confirm the following at each unit:
  • Shipping restraints, blocking, and protective films have been removed
  • The fan rotates freely and in the correct direction
  • The filter is installed, is the scheduled rating and size, and can be withdrawn
  • The coil is filled, vented, and pressure tested with the system
  • The drain pan drains completely with water introduced at the far end, and the trap is primed
  • The water-level detection device stops the cooling source when the pan is filled to its trip level
  • The electric heater circuit, where furnished, is energized and the airflow proving device reads a no-flow condition with the fan off
  • The control devices are mounted, wired to the terminal strip per the diagram, and the zone sensor reports a plausible temperature
  • Network communication is established with the controller at its assigned address where a networked controller is furnished
  • Access panels are closed and the ceiling or the cabinet front is complete
Pre-Startup Inspection Checklistcheckbox
☑ Shipping restraints and protective films removed
☑ Fan rotates freely in the correct direction
☑ Scheduled filter installed and withdrawable
☑ Coil filled, vented, and pressure tested
☑ Drain pan drains completely and trap primed
☑ Water-level detection device stops the cooling source
☐ Electric heater circuit energized and airflow proving device verified
☑ Control devices mounted, wired per diagram, and zone sensor reporting
☐ Network communication established at the assigned address
☑ Access panels closed and finish complete
20.7.2 Units shall not be operated to provide temporary heating, cooling, or ventilation during construction unless the Engineer of Record accepts the temporary use in writing and the Contractor replaces every filter and cleans every coil, pan, and casing so operated before Substantial Completion.

21 Field Testing and Commissioning

21.1 Airflow and Water Flow Verification

21.1.1 The testing and balancing agent shall verify the airflow at each unit at the design fan speed and at each other speed the occupant or the controller can select, in accordance with Testing Adjusting And BalancingTesting, Adjusting, and Balancing for HVACResolves to the current adopted revision.sync/testing-adjusting-and-balancing.
21.1.2 The testing and balancing agent shall set and verify the water flow through each coil at the scheduled flow, in accordance with Testing Adjusting And BalancingTesting, Adjusting, and Balancing for HVACResolves to the current adopted revision.sync/testing-adjusting-and-balancing, using the balancing or flow-limiting device furnished in the connection package.
21.1.3 Where a pressure-independent control valve is furnished, the scheduled flow shall be set at the valve and verified at the valve's own measurement ports rather than with a separate balancing device.
21.1.4 Verification shall be performed with the ceiling complete, the scheduled filter installed and clean, and the plant operating at its design supply temperature and differential pressure.
21.1.5 Where a unit cannot be brought to the scheduled airflow at the design fan speed or to the scheduled water flow, the testing and balancing agent shall report the condition to the Engineer of Record rather than raising the fan speed or the valve setting to match the schedule.
NOTE Raising the fan speed to recover a shortfall recovers the airflow at the sound level of the higher speed, which the room was not selected for, and it is the quiet substitution that turns an airflow deficiency into a noise complaint after the balancing report has closed. (21.1.6)

21.2 Functional Performance Testing

21.2.1 The extent of functional performance testing shall be as indicated in the datasheet.
Extent of Functional Performance Testingradio
○ Not required
○ Representative sample of units of each configuration
○ Every installed unit
NOTE A fan-coil installation is many copies of a few configurations, and a sample of each configuration finds the defects that are in the design and the submittal. Testing every unit finds the defects that are in the field, which on these units are the mis-wired float switch, the valve left open, and the sensor wired to the wrong terminal, each of which is invisible from a sample of other units. The choice follows what the project can afford to find later: a hotel finds a mis-wired unit from a guest complaint, and a hospital finds it from a ceiling stain in a patient room. (21.2.2)
21.2.3 Where functional performance testing is required, it shall be conducted in accordance with ANSI/ASHRAE 202 and CommissioningTotal Building CommissioningResolves to the current adopted revision.sync/commissioning, and shall verify the zone control sequence in occupied, unoccupied, and setback modes, the fan speed response, the valve operation through its range, the changeover response where a changeover coil is furnished, the electric heater staging and airflow interlock where a heater is furnished, the overflow protection device, and the reporting of every point to the building automation system where a networked controller is furnished.
21.2.4 Where a functional performance test fails, the Contractor shall correct the deficiency and shall bear the cost of retesting that unit.
21.2.5 Where a sample-based extent is selected and a unit in the sample fails, the sample for that configuration shall be doubled at the Contractor's expense.
21.2.6 The as-left fan speed, the as-left flow setting, and the result of each test shall be recorded for each unit in the field startup and verification record.

22 Identification

22.1 Each unit shall be furnished with a permanent identification label applied to the casing exterior in a location visible with the unit installed and the access panel closed.
22.2 The identification label shall state the unit tag matching the unit schedule, the manufacturer's model and serial number, the airflow at the design fan speed, the cooling and heating capacity, the electric heater rating where furnished, the electrical characteristics including the minimum circuit ampacity and the maximum overcurrent protective device rating, the filter size and rating, the controller address where a networked controller is furnished, and the date of manufacture.
22.3 Identification labels shall not be applied to a removable access panel or to the finished front of an exposed cabinet.
22.4 The identification label shall be an adhesive laminated label or an engraved plate secured to the casing, and on a unit installed in a natatorium, a kitchen, or a corrosive space it shall be an engraved plate mechanically fastened to the casing.
22.5 The filter access panel shall be labeled with the filter size and rating the unit holds.
22.6 Where a unit is replaced or its configuration is changed after the label is applied, the label shall be replaced to reflect the as-installed configuration.

23 Warranty

23.1 The manufacturer shall warrant each unit against defects in materials and workmanship, parts and labor, for the term indicated in the datasheet, beginning at the date of Substantial Completion.
Unit Warranty Termrange
Not less than
years
123510
23.2 The unit warranty shall cover the casing, the liner, the coils, the drain pan, the fan and motor, the electric heater, the integral risers, the condensate pump, and every control device and connection package component furnished by the unit manufacturer.
23.3 The fan motor and its integral electronics, each hydronic coil, and each integral riser shall be covered against defects and against leakage in the tube, fin, header, and joint assembly for not less than the unit warranty term, and where the manufacturer offers a longer motor warranty, its term and conditions shall be stated in the submittal.
23.4 The Contractor shall warrant the installation, including hangers, isolation, riser joints, duct and piping connections, condensate connections, electrical connections, control wiring, insulation at the unit, and identification, for the term indicated in the datasheet, beginning at the date of Substantial Completion.
Installation Warranty Termrange
Not less than
years
1235
23.5 Warranty coverage shall include the cost of removing and reinstalling the ceiling, the cabinet front, the ductwork, and the piping disturbed to reach a unit being repaired or replaced, and the cost of repairing collateral damage caused by that work.
23.6 Where a unit or a component is repaired or replaced under warranty, the repaired or replacement item shall carry a fresh warranty of the full original term from the date of the repair, or the remainder of the original term, whichever ends later.
23.7 The Contractor shall keep every installed unit accessible during the warranty period by keeping access panels, ceiling tiles, cabinet fronts, and adjacent construction clear of permanent obstruction.
23.8 The manufacturer shall maintain factory-trained service capability within the region of the project for the duration of the unit warranty term.
23.9 The manufacturer's warranty shall not be voided by a filter change, a drain pan cleaning, a fan speed adjustment, or a control device replacement performed in accordance with the operation and maintenance manual by a qualified technician.

24 Spare Parts

24.1 The Contractor shall deliver the following to the Owner at Substantial Completion:
  • One complete set of filters of every size and rating installed
  • Two complete sets of filters of every size and rating installed
  • One fan motor of each size and type installed
  • One control valve actuator for each actuator model installed
  • One zone controller for each controller model furnished by the unit manufacturer
  • One water-level detection device of each model installed
  • One condensate pump of each model installed
  • Zone sensors or thermostats equal to five percent of the installed quantity, and not fewer than two
  • One primary and one secondary thermal cutout for each electric heater model installed
  • One set of access panel fasteners and gaskets for each unit configuration
Spare Parts Furnishedcheckbox
☑ One complete set of filters of every size and rating
☐ Two complete sets of filters of every size and rating
☑ One fan motor of each size and type
☑ One control valve actuator for each actuator model
☐ One zone controller for each controller model furnished by the unit manufacturer
☑ One water-level detection device of each model
☐ One condensate pump of each model
☐ Zone sensors or thermostats equal to five percent of the installed quantity
☐ One primary and one secondary thermal cutout for each heater model
☐ One set of access panel fasteners and gaskets for each configuration
NOTE Fan-coil units are direct-drive, so no drive belts are furnished as spares, and the fan motor is the spare that keeps a room in service while a failed motor is on order. (24.2)
24.3 Spare parts shall be delivered in the manufacturer's original packaging, each tagged with the model number, the unit tags it serves, and the date of delivery.
24.4 Spare parts shall be turned over at a storage location the Owner designates, and the transfer shall be documented in the closeout submittal.
24.5 The operation and maintenance manual shall include a spare parts inventory listing the manufacturer part number and reorder information for every component of the units furnished, and a filter change schedule derived from the initial and change-out resistances stated in the submittal.

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"Fan-Coil Units," SynC Standards, revision 4. Licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://synergyinconstruction.com/standards/general/fan-coil-units. Reference material only; not professional engineering advice and provided without warranty. Verify against governing codes and have a licensed professional review before use.