Chillers

This specification covers packaged factory-assembled liquid chillers using vapor-compression refrigeration to produce chilled water for HVAC service. Equipment covered includes the complete chiller package as shipped from the manufacturer: compressor(s) with drive, evaporator (cooler), condenser, refrigerant circuit and charge, lubrication system, microprocessor unit controller, integral power and control enclosure, factory-mounted starter or variable frequency drive where applicable, and the integral accessories listed under Accessories & Options. Both water-cooled chillers (using a separate condenser water loop served by a cooling tower or other heat rejection source) and air-cooled chillers (rejecting heat directly to ambient air through integral condenser fans) are addressed.

A chiller is a single integrated machine but it sits at the center of a system. Its performance, reliability, and service life depend as much on the design and condition of the systems connected to it — the condenser water loop, the chilled water distribution, the electrical service, and the building automation system — as on the machine itself. The Contractor shall coordinate chiller installation with HVAC PumpsThis citation does not resolve.syncs/hvac-pumps for chilled water and condenser water pumps, Hydronic PipingThis citation does not resolve.syncs/hydronic-piping for piping sizing and arrangement at the chiller connections, HVAC Water TreatmentThis citation does not resolve.syncs/hvac-water-treatment for both closed-loop chilled water chemistry and open-loop condenser water chemistry and Legionella risk management, Building Automation SystemThis citation does not resolve.syncs/building-automation-system for control integration, Testing Adjusting And BalancingThis citation does not resolve.syncs/testing-adjusting-and-balancing for system flow verification, Concrete PadsThis citation does not resolve.syncs/concrete-pads for the housekeeping pad, Grounding And BondingThis citation does not resolve.syncs/grounding-and-bonding for equipment grounding, and Equipment LabelingThis citation does not resolve.syncs/equipment-labeling for nameplate and arc-flash labeling.

The boundary of work under this standard is the chiller package itself, from the chilled water and condenser water connections (or, for air-cooled units, the chilled water connections only) through the integral power and control terminations. Field-installed piping, valves, strainers, flow meters, and isolation devices on the connected loops are covered in Hydronic PipingThis citation does not resolve.syncs/hydronic-piping. The cooling tower and condenser water heat rejection system, including the tower itself and its sump piping, are covered in the cooling tower standard. The chilled water distribution beyond the chiller connections, including primary/secondary decoupling, distribution pumps, and air separation, is covered in Hydronic PipingThis citation does not resolve.syncs/hydronic-piping and HVAC PumpsThis citation does not resolve.syncs/hvac-pumps.

Performance rating shall conform to AHRI 550/590 (I-P) or AHRI 551/591 (SI) for water-chilling packages. Sound rating shall conform to AHRI 575. Energy efficiency shall meet or exceed the minimums of ANSI/ASHRAE/IES 90.1 for the applicable chiller type, capacity, and condenser type. Refrigerant safety and machinery room requirements shall conform to ASHRAE 15. Refrigerant designation and safety classification shall conform to ASHRAE 34. Pressure vessels (evaporator and condenser shells) shall conform to ASME Section VIII, Division 1. Refrigerant piping integral to the package shall conform to ASME B31.5. Electrical safety listing shall be UL 1995 or UL 60335-2-40 as accepted by the Authority Having Jurisdiction. Field electrical installation shall conform to NFPA 70 (NEC) Article 440.

Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited. Where conflicts exist between referenced standards, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.

Where the project is located in a jurisdiction that has adopted local energy codes more stringent than ASHRAE 90.1 (for example, Title 24 in California, Stretch Code amendments in the Northeast, or local high-performance building ordinances), the local efficiency requirement shall govern.

The Contractor shall submit the following for the Engineer's review and acceptance prior to procurement. Fabrication and shipment shall not proceed until action submittals have been reviewed and returned.

• Manufacturer's product data sheets and catalog cuts for each chiller, including model designation, refrigerant, dimensional and weight data (operating and shipping), and identification of all factory-mounted accessories
• Certified AHRI performance data per AHRI 550/590 (or 551/591) at the project design conditions, including full-load efficiency (kW/ton and COP), IPLV.IP (or NPLV per AHRI 550/590-2023 path), and the performance at the specific design entering and leaving water temperatures and fouling factors
• Off-design performance data showing capacity and efficiency at part-load points across the operating envelope, including operation at minimum load and at the design wet-bulb (for water-cooled) or design dry-bulb (for air-cooled) approach to ambient
• Refrigerant designation per ASHRAE 34, safety classification, system charge weight, ASHRAE 15 occupancy classification for the machinery room, and refrigerant monitoring requirements
• Sound power level data per AHRI 575 in octave bands from 63 Hz through 8 kHz, and sound pressure level at 30 ft (10 m) and at the nearest noise-sensitive receptor
• Compressor data including type, number of compressors and refrigerant circuits, compressor drive type (hermetic, semi-hermetic, open-drive, magnetic-bearing oil-free), and operating speed or speed range for variable-speed compressors
• Evaporator data including shell-and-tube construction, tube material and gauge, water-side and refrigerant-side pressure drop, water-side fouling factor used in selection, and minimum and maximum allowable flow rates
• Condenser data including (for water-cooled) shell-and-tube construction matching the evaporator data plus condenser water flow rate, pressure drop, and fouling factor, or (for air-cooled) coil construction, fan arrangement, ambient air flow, and the design ambient dry-bulb
• Electrical data including unit nameplate voltage, FLA, MCA (minimum circuit ampacity), MOCP (maximum overcurrent protection), inrush current, starter type (across-the-line, solid-state soft-start, VFD), and short-circuit current rating (SCCR)
• Starter or integral VFD data sheets where furnished as part of the chiller package
• Unit controller product data including the integral microprocessor, operator interface, network communications (BACnet, Modbus, LonWorks) and points list
• Refrigerant relief device data including relief pressure setting, capacity, and vent piping recommendations per ASHRAE 15
• Lifting and rigging diagrams identifying lift points and operating and shipping weights
• Seismic restraint calculations and details where required by the applicable building code
• Coordination drawings showing chiller location, required service clearances (tube pull, compressor service, control panel access), and the integration of refrigerant relief vent piping with the machinery room

At substantial completion, the Contractor shall provide the following before the chiller is accepted.

• Manufacturer's installation, operation, and maintenance manual covering the as-shipped configuration
• As-built nameplate data including serial number, model number, manufactured date, refrigerant type and factory charge weight, and the installed motor and starter serial numbers
• Factory test reports (run test, electrical test, leak test, and where specified, witnessed performance or sound test)
• Field startup report by the manufacturer's factory-authorized service representative, including measured chilled water flow, condenser water flow (water-cooled), entering and leaving water temperatures, ambient conditions (air-cooled), compressor amperage, oil pressure, refrigerant pressures, and superheat/subcooling
• Refrigerant charge verification and any field-added refrigerant logged by type, quantity, and date
• BAS integration documentation including points list as-built, mapping to the BAS, and verified communication
• Warranty documentation correlating serial number, startup date, and warranty expiration
• Recommended spare parts list with manufacturer part numbers
• Training records for Owner's operating personnel

Chillers shall be the products of a manufacturer with a minimum of fifteen years of continuous experience designing and producing the specific chiller type and size range required for this project. The manufacturer shall maintain an ISO 9001 certified quality management system. Parts and factory-authorized service shall be available for the chiller model line for a minimum of twenty years from the date of manufacture. Local factory-authorized service shall be available within a four-hour response radius of the project site for startup, warranty service, and emergency response.

Each chiller shall be a model that participates in the AHRI Water-Chilling Packages Certification Program covering AHRI 550/590 and AHRI 551/591. Catalog ratings shall be certified by AHRI; non-certified ratings are not acceptable for compliance with this standard.

The evaporator and condenser shells (and any other refrigerant-containing pressure vessels above the ASME Section VIII Division 1 size threshold) shall be designed, fabricated, inspected, and stamped in accordance with ASME Section VIII, Division 1. The "U" stamp and the manufacturer's data report (Form U-1) shall be provided. The complete chiller package shall be listed and labeled to UL 1995 or UL 60335-2-40 by a Nationally Recognized Testing Laboratory.

The compressor(s), evaporator, condenser, refrigerant charge, oil charge, unit controller, integral starter or variable frequency drive, and all factory-mounted accessories shall be furnished as a coordinated assembly by a single chiller manufacturer. Field assembly of major components from separate suppliers is not acceptable. The manufacturer shall be responsible for the performance, reliability, and warranty of the complete package.

Initial startup and commissioning of each chiller shall be performed by the manufacturer's factory-trained and factory-authorized service technician. The startup technician shall be on site for the duration of the initial fill, leak check, oil and refrigerant verification, controls programming, and the functional performance test. The Contractor shall not start the chiller for any purpose prior to manufacturer's startup, except for short uncoupled motor rotation checks performed under the manufacturer's written instructions.

A pre-installation conference shall be held before chiller installation begins, attended by the mechanical contractor, the electrical contractor, the controls contractor, the TAB agent, the chiller manufacturer's representative, and the Owner's representative. Agenda shall include rigging and setting sequence, structural and pad coordination, refrigerant relief vent routing, chilled water and condenser water connection sequence, electrical service and SCCR coordination, BAS integration, ASHRAE 15 machinery room provisions, and the startup schedule.

Water-cooled chillers are almost always installed indoors in a dedicated mechanical room or central plant; the cooling tower handles the outdoor heat rejection. Air-cooled chillers are installed outdoors so that the integral condenser can reject heat directly to ambient air; typical locations are an at-grade concrete pad, a structural-steel roof platform, or a roof curb. Locating an air-cooled chiller in a sound-sensitive courtyard or against a building face where condenser air recirculates back into the unit is a common error that both reduces capacity and increases noise complaints. Coordinate location with the architectural and structural drawings and confirm prevailing wind direction and sound receptor locations.

Where the chiller is installed indoors, the room shall be classified and arranged in accordance with ASHRAE 15. The room classification depends on the refrigerant type, charge size, and occupancy of adjacent spaces, and may require refrigerant leak detection, mechanical ventilation, separation from occupied spaces, and emergency shutdown. Compliance is the responsibility of the design team; this standard requires that the chiller manufacturer provide the data needed for the classification (refrigerant designation per ASHRAE 34, total system charge weight, recommended refrigerant monitor type and sensor placement).

Refrigerant monitoring inside the machinery room shall be provided where required by ASHRAE 15 or the local mechanical code. The monitor shall alarm at the refrigerant concentration limit (RCL) for the applicable refrigerant and initiate the mechanical ventilation and the emergency shutdown of the chiller per the design.

Air-cooled chillers shall be selected at the project's actual design dry-bulb temperature, not at the 95°F AHRI rating point. A chiller selected only at 95°F and installed in a desert climate with a 110°F design dry-bulb will deliver substantially less capacity at peak conditions. Where the chiller is expected to operate at low ambient temperatures (winter operation for process cooling, data centers, or buildings with year-round cooling load), the unit shall be furnished with the manufacturer's low-ambient package: head pressure control by condenser fan cycling or VFD control of condenser fans, and the appropriate refrigerant charge management.

Air-cooled chiller capacity is reduced at altitude because the lower air density reduces condenser heat rejection. Electric motor cooling is also reduced at altitude. The chiller manufacturer shall confirm net capacity and motor selection at the project altitude for any installation above 3,000 ft.

Cooling capacity shall be expressed in tons of refrigeration (1 ton = 12,000 Btu/hr) at the design entering and leaving chilled water temperatures, design condenser conditions, and design fouling factors. The selected chiller capacity shall meet or exceed the design block load with no positive tolerance (per AHRI 550/590, the rated capacity is a single point with tolerance permitted by the AHRI test method, not a margin to be applied during selection).

Leaving chilled water temperature (LCHW) of 44°F with a 12°F range (56°F entering) is the long-standing comfort-cooling default and is the AHRI 550/590 standard rating point. Lower leaving temperatures (40°F to 42°F) increase cooling tower load and reduce evaporator capacity, but enable smaller chilled water pumps and piping at a given load. Higher leaving temperatures (45°F to 48°F) improve chiller efficiency and are common in projects optimized for low pumping energy or for use with chilled-beam systems. The design ΔT shall be coordinated with the chilled water distribution design in Hydronic PipingThis citation does not resolve.syncs/hydronic-piping and the air-side coil selections; mismatch between the chiller ΔT and the coil ΔT produces "low ΔT syndrome" in the distribution system.

Entering condenser water (ECW) of 85°F with a 10°F range (95°F leaving) is the AHRI 550/590 standard rating point and represents a typical cooling tower performance at the U.S. ASHRAE 1% wet-bulb. Lower ECW improves chiller efficiency substantially — every 1°F reduction in ECW typically reduces full-load kW/ton by approximately 1% to 2% — but requires a larger cooling tower or a lower design wet-bulb. The selected ECW shall be coordinated with the cooling tower selection.

Air-cooled chillers are rated at 95°F ambient dry-bulb per AHRI 550/590. Selection at the project's actual design dry-bulb is required where it exceeds the rating condition. Air-cooled chillers experience the largest capacity loss at peak ambient conditions, and the design block load shall be coordinated with the design ambient — not with the AHRI rating ambient — to avoid under-sizing.

Fouling factor is an allowance for heat transfer surface degradation between cleanings. AHRI 550/590 rates chillers at 0.00010 hr·ft²·°F/Btu on both sides; this represents essentially new, clean tubes. Real condenser water service with conventional chemical treatment results in some scale and biofilm accumulation between cleanings, and most design engineers apply a higher condenser fouling factor for selection — typically 0.00025 — to size the chiller for end-of-service-interval performance. The fouling factor used in selection shall be reported on the AHRI submittal and matched to the cleaning interval defined in the operations and maintenance plan.

Each chiller shall meet or exceed the minimum full-load and integrated part-load efficiency requirements of ASHRAE 90.1 for the equipment class (water-cooled vs. air-cooled), compressor type (centrifugal, positive displacement), and capacity range. The applicable minimum shall be confirmed against the ASHRAE 90.1 edition adopted by the local jurisdiction; for many jurisdictions this is ASHRAE 90.1-2019 or 2022. The selected efficiency shall be the more stringent of the local energy code, ASHRAE 90.1, or the project-specific values shown on the contract drawings.

ASHRAE 90.1 offers two compliance paths for chillers. Path B (the higher part-load path) is generally preferred for typical commercial buildings because most operating hours occur at part load, and total annual chiller energy is dominated by part-load operation. Path A may be appropriate for chillers that operate predominantly at full load (district energy plants, process cooling with steady demand).

Full-load efficiency is expressed as kW/ton (lower is better) or COP (higher is better). Water-cooled centrifugal chillers at standard AHRI conditions commonly achieve 0.50 to 0.60 kW/ton, with high-efficiency centrifugal machines reaching 0.45 kW/ton or lower at the rating point. Water-cooled screw chillers typically achieve 0.55 to 0.65 kW/ton. Air-cooled chillers are inherently less efficient because of the higher condensing temperature dictated by air-side heat transfer, and typical full-load efficiency is 0.95 to 1.15 kW/ton for screw chillers and 1.10 to 1.30 kW/ton for scroll chillers. The values shown above are typical and shall be coordinated with the ASHRAE 90.1 minimum.

IPLV.IP is a single-number weighted average efficiency at 100%, 75%, 50%, and 25% of full load with corresponding condenser conditions, computed per AHRI 550/590. It is the most commonly reported indicator of part-load performance and is the basis of ASHRAE 90.1 Path B compliance. IPLV.IP is computed at the AHRI standard rating point and assumes a single, isolated chiller; it does not directly represent annual energy at the project. For buildings with unusual load profiles (year-round cooling, low minimum load, or chiller plants with sequencing), the Engineer should also evaluate the chiller at the specific NPLV (non-standard part-load value) condition reflecting the actual sequence and condenser-water reset strategy.

For critical applications — district energy, data centers, central plants serving multiple buildings — the specification may include a performance penalty clause that imposes a monetary deduction if the field-measured kW/ton at the design condition exceeds the certified rating, or witness factory performance testing on the specific machine before shipment. For most commercial projects, the manufacturer's AHRI-certified rating is sufficient.

Refrigerant selection is governed by the EPA Significant New Alternatives Policy (SNAP) program, the American Innovation and Manufacturing (AIM) Act phase-down of HFCs, and the chiller manufacturer's product line. R-134a remains widely available for new equipment but is subject to the HFC phase-down; R-513A is a near-drop-in lower-GWP replacement with similar performance and ASHRAE 34 A1 (nontoxic, nonflammable) safety classification. R-1233zd(E) and R-1234ze(E) are low-pressure HFO refrigerants used in centrifugal chillers and offer GWP below 1; R-1234ze(E) is A2L (mildly flammable) and requires additional safety provisions per ASHRAE 15. R-32 and R-454B are A2L refrigerants common in newer scroll and screw equipment.

The selected refrigerant shall (1) be currently EPA SNAP-approved for the equipment type, (2) be supported by the chiller manufacturer for the equipment model, (3) be permitted by the local jurisdiction's adopted edition of ASHRAE 15 for the machinery room classification, and (4) align with the Owner's long-term refrigerant strategy where the Owner has expressed one.

Smaller chillers (scroll, smaller screw) typically ship factory-charged with the operating refrigerant; larger chillers (centrifugal and large screw) frequently ship with a nitrogen holding charge and are field-charged at startup. Where the chiller will be field-charged, the manufacturer's startup technician shall be responsible for the charging and the refrigerant shall be supplied as part of the chiller package.

Each refrigerant-containing pressure vessel shall be protected by a relief device sized and selected per ASHRAE 15 and ASME Section VIII. Relief devices shall discharge to outdoors through a vent line sized per ASHRAE 15. The relief vent line is part of the field-installed scope and shall be coordinated with the chiller's relief device location, capacity, and recommended pipe size.

Compressor type is the single most consequential machine-level decision and is generally tied to chiller size and configuration. Centrifugal compressors dominate the water-cooled market above approximately 200 tons because of their high efficiency, smooth modulation, and durability; below 200 tons, screw compressors are competitive on first cost and efficiency. Scroll compressors dominate air-cooled chillers below approximately 200 tons, with multiple scrolls staged across one or more refrigerant circuits to provide capacity modulation and redundancy. Magnetic-bearing oil-free centrifugal compressors eliminate the oil system entirely, offer excellent part-load efficiency through high-speed operation on magnetic bearings, and are particularly attractive for buildings with high part-load operating hours.

Redundancy is a function of the project's tolerance for outage. A single-circuit chiller is the simplest and most efficient configuration, but a refrigerant leak or compressor failure removes 100% of the unit's capacity. A dual-circuit chiller continues to operate at approximately 50% capacity when one circuit is offline, which is acceptable for many commercial applications and shifts the redundancy decision toward a single chiller rather than two smaller chillers. For critical applications, dual-circuit chillers and multiple chillers in parallel are both common.

Variable-speed compressor drive substantially improves part-load efficiency by allowing the compressor to slow as load drops, instead of throttling refrigerant flow with inlet guide vanes (centrifugal) or slide valves (screw) while running at full speed. For typical commercial cooling load profiles — significant operating hours below 50% load — a VFD payback is often two to four years. The trade-off is increased first cost, additional harmonic distortion on the building electrical service that may require mitigation, and the VFD's own service requirements.

The compressor shall be arranged for in-place service of routine items (oil filters, sensors, terminations) without removing the compressor from the chiller, and shall be removable from the chiller for major service (rebuild or replacement) through a defined service path. The Contractor shall coordinate machinery room clearances with the manufacturer's required service access; the typical centrifugal compressor service clearance is the full length of the chiller plus space for the compressor rotor or impeller withdrawal.

Flooded shell-and-tube evaporators are standard for centrifugal and most screw chillers and provide the highest efficiency because of their large refrigerant-side heat transfer area and their ability to operate at a small refrigerant-to-water temperature approach. Direct-expansion (DX) evaporators are used in many screw and scroll chillers and have a smaller refrigerant charge per ton at the cost of a slightly larger approach. Brazed-plate evaporators are common in small scroll air-cooled chillers and offer compactness and very low refrigerant charge.

Copper with enhanced surfaces (rifled, integrally finned, or otherwise textured) is the standard evaporator tube and provides excellent heat transfer in clean treated chilled water service. Copper-nickel, stainless steel, and titanium tubes shall be specified where the chilled water source is non-standard — for example, process water with chloride content, recovered water, or geothermal source loops with aggressive chemistry.

Marine waterboxes — removable end covers that allow the tubes to be brush-cleaned without disconnecting the chilled water piping — are recommended for chillers in service longer than 10 years where periodic tube cleaning is planned. Standard waterboxes are acceptable for chillers in clean treated closed-loop service where tube cleaning will be infrequent.

The evaporator and connected piping operate below dew-point and require continuous vapor-tight insulation. Factory-applied closed-cell foam on the evaporator shell, waterboxes, and refrigerant suction lines is strongly preferred because the factory installation eliminates field labor on a complex shape and ensures continuous coverage. Field-applied insulation is acceptable only where access for the factory application is impractical.

Water-cooled condenser construction parallels the evaporator: shell-and-tube with copper or alloy tubes, marine or standard waterboxes, flanged or grooved water connections, and waterbox vents and drains. A subcooler section at the condenser outlet increases refrigerant liquid subcooling, improves cycle efficiency, and is standard on most centrifugal and screw chillers.

Marine waterboxes are strongly recommended for water-cooled condensers because open-loop condenser water service produces scale and biofilm on tube interiors that must be brushed out periodically. Automatic tube brush cleaning systems circulate small brushes through the condenser tubes continuously and substantially reduce manual cleaning labor; they are common on large central plants in continuous service.

Air-cooled condenser coils consist of refrigerant-carrying tubes (copper or aluminum microchannel) with extended fins (aluminum, copper, or coated) to maximize air-side heat transfer area. Standard copper-tube aluminum-fin construction is appropriate for most outdoor installations. Microchannel all-aluminum coils are compact, contain less refrigerant per ton, and resist some types of corrosion, but a small leak in a microchannel section typically requires replacement of the entire coil segment because individual tubes are not field-repairable. E-coated coils provide additional corrosion protection for coastal, urban, and industrial environments where airborne chlorides, sulfides, or particulates would otherwise degrade the standard fin material.

Condenser fans dominate the off-design noise signature of an air-cooled chiller and are also a significant parasitic load. Variable-speed condenser fans (either EC motor-equipped fans or VFD-driven AC fans) allow head pressure control as ambient temperature drops, reduce fan power at part load, and substantially reduce off-design sound — especially at night when both ambient temperature and noise constraints favor low fan speed. Fixed-speed fans cycled on/off by head pressure controls are acceptable but produce step changes in noise and capacity.

Voltage selection shall match the building electrical service available at the chiller location. Low-voltage 460V or 480V service is standard for chillers up to approximately 1,000 tons. Medium-voltage service (2,300V or 4,160V) is used for very large centrifugal chillers where the low-voltage motor and feeder size become impractical; this is a system-level decision coordinated with the electrical engineer and may require dedicated transformers, switchgear, and operator qualification considerations.

Across-the-line starting produces compressor inrush currents on the order of six to eight times full-load amperes and can cause unacceptable voltage dips on the building service for any chiller above approximately 100 tons. Solid-state soft starters reduce inrush at the cost of higher first cost and additional heat to manage. VFDs eliminate the inrush problem entirely (VFD starting current is essentially full-load), provide variable-speed compressor operation for part-load efficiency, and are the standard starter type for new chillers above approximately 75 tons. Coordinate with the electrical engineer for short-circuit current rating (SCCR), maximum inrush, and harmonic compatibility with the building service.

Factory-mounted and factory-wired integral starters and VFDs eliminate field power wiring between the starter and the compressor and avoid the cable length and filtering issues associated with remote-mounted VFDs. Remote starters are appropriate where machinery room thermal load must be minimized, where the starter or VFD requires its own cooled enclosure, or where service access to the starter is poor at the chiller location. Where a VFD is remote-mounted, the cable length and motor filtering requirements of HVAC Variable Frequency DrivesThis citation does not resolve.syncs/hvac-variable-frequency-drives shall be applied to the chiller-to-VFD run.

The chiller's SCCR shall meet or exceed the available fault current at the chiller line-side terminals as established by the electrical engineer's short-circuit study. SCCR below the available fault current is a code violation under NFPA 70 and a safety hazard. Coordinate the SCCR with the upstream protection coordination study.

Each chiller shall be furnished with an integral microprocessor-based unit controller that performs all safeties, capacity control, refrigerant management, and condenser management. The controller shall include an operator interface (graphical color display preferred, monochrome acceptable for smaller chillers) mounted on the chiller for local operation. Controller programming shall be the manufacturer's standard with all parameters required for proper operation at the design conditions configured at the factory.

BACnet/IP is the preferred protocol for new commercial buildings and is the protocol assumed by Building Automation SystemThis citation does not resolve.syncs/building-automation-system. The chiller shall be a BACnet-certified Application Specific Controller (B-ASC) at minimum, with the manufacturer's published BACnet PICS (Protocol Implementation Conformance Statement) made available. Modbus and LonWorks remain in service in legacy buildings and may be specified where consistency with an existing BAS is required. Proprietary protocols with vendor-specific gateways shall be avoided where the chiller will outlive the gateway and where future BAS replacement is anticipated.

Where multiple chillers operate in a plant, sequencing and chilled water temperature reset shall be coordinated with the chilled water plant design. The chiller's integral controller shall accept BAS-commanded chilled water setpoint, demand limit, and enable/disable; complex plant sequencing logic (chiller selection, condenser water reset, primary/secondary pump control) resides in the BAS or in a dedicated plant controller, not in the chiller unit controller.

Sound rating shall be certified per AHRI 575 (machinery room sound) for water-cooled chillers and per AHRI 575 or the manufacturer's equivalent free-field method for air-cooled chillers. The sound rating shall be reported as octave-band sound power levels (63 Hz through 8 kHz) and as A-weighted sound pressure level at the standard distance. For air-cooled chillers, both full-speed and reduced-speed (night setback) sound shall be reported where variable-speed condenser fans are provided.

Air-cooled chillers installed near noise-sensitive boundaries (residential property lines, hospital windows, office facades) frequently require multiple sound mitigation measures: low-noise fan packages, variable-speed fans for night setback, sound walls or screens, and careful site arrangement to direct fan exhaust away from sensitive receptors. The Engineer shall confirm the design sound level at the nearest receptor against the applicable noise ordinance and the project sound criteria.

Where required by the IBC and ASCE 7 based on the seismic design category and equipment importance factor, chillers shall be provided with seismic restraints. Restraints shall be designed to permit the vibration isolators to function normally under operating loads while limiting motion during a seismic event to a level that does not damage attached refrigerant piping, water piping, or electrical connections. Seismic restraint calculations shall be sealed by a professional engineer licensed in the project jurisdiction.

Heat recovery chillers reject condenser heat to a useful destination — domestic hot water preheat, building heating loop, swimming pool heating, snow-melt — rather than to a cooling tower or outdoor air. Partial heat recovery uses a small auxiliary condenser to capture a portion of the heat at moderate temperature; full heat recovery uses a complete second condenser to produce heating-temperature water (typically 105°F to 140°F) at the same time the chiller produces chilled water. Heat recovery is highly application-specific and shall be evaluated against the project's coincident heating and cooling loads.

Where the project includes a waterside economizer (a plate-and-frame heat exchanger that bypasses the chiller when condenser water is cold enough to produce chilled water directly), the chiller controls shall coordinate with the economizer sequence and the chiller shall safely shut down when economizer operation alone meets the load. Some air-cooled chillers include integral refrigerant-side free cooling that uses ambient air at low temperatures to cool the refrigerant directly without running the compressor; this is a manufacturer-specific option useful in cold climates with year-round cooling load.

The manufacturer shall perform the following factory tests on each chiller before shipment:

• Pressure test (leak test) of the refrigerant circuit at the manufacturer's specified test pressure, with no detectable leakage
• Evacuation and vacuum hold of the refrigerant circuit prior to charging or holding-charge fill
• Hydrostatic test of the water-side circuits (evaporator and condenser) per ASME Section VIII Division 1 requirements
• Mechanical run test of the assembled chiller — for centrifugal and screw chillers this is a no-load run with the refrigerant circuit charged to verify rotation, oil pressure, vibration, and controller function
• Electrical test of the integral power and control circuits, including continuity, insulation resistance, and protective function verification
• Verification of all factory-set safety setpoints (high-pressure cutout, low-pressure cutout, freeze protection, oil pressure, overcurrent)

Witness performance testing is reserved for large centrifugal chillers, district energy applications, mission-critical installations, and projects with tight performance envelopes. Where specified, the witness test shall be conducted at the manufacturer's certified test stand with calibrated instrumentation, at conditions reproducing the design point as closely as the test stand permits, and the Owner's representative and the Engineer shall be given adequate advance notice to attend.

Before manufacturer's startup, the Contractor shall complete the following with the chiller isolated electrically and hydraulically:

• Verify the chiller has been set on its housekeeping pad, leveled, anchored, and that any seismic restraints are installed per the manufacturer's instructions
• Verify chilled water and condenser water piping is complete, pressure-tested, flushed, and refilled per Hydronic PipingThis citation does not resolve.syncs/hydronic-piping and HVAC Water TreatmentThis citation does not resolve.syncs/hvac-water-treatment
• Verify all flow switches, pressure taps, and instrumentation are installed and the flow paths through the evaporator and condenser are correct
• Verify electrical power termination at the chiller is complete, the SCCR is adequate for the available fault current, and ground per Grounding And BondingThis citation does not resolve.syncs/grounding-and-bonding
• Verify the refrigerant relief vent piping is installed, routed to outdoors, and supported per ASHRAE 15
• Verify the BAS communication wiring is installed and the chiller has been added to the BAS database per Building Automation SystemThis citation does not resolve.syncs/building-automation-system
• Verify the machinery room ventilation, refrigerant monitor, and emergency shutdown per ASHRAE 15 are installed and functional

The manufacturer's factory-authorized service technician shall perform the following:

• Verify factory holding charge or operating refrigerant charge
• Evacuate the refrigerant circuit if shipped with a holding charge, and charge with the operating refrigerant
• Verify oil charge and oil temperature; energize oil heater for the manufacturer's specified soak time before first start
• Confirm rotation direction by jogging the compressor (or by VFD with limited acceleration) before sustained operation
• Start the chiller and operate at minimum load to verify safeties, alarms, and shutdowns function correctly
• Bring the chiller up through its operating range to design load (where the connected system permits) and record full operating data
• Configure controller parameters for the project — chilled water setpoint, demand limit defaults, condenser-water reset (water-cooled), low-ambient operation (air-cooled), and BAS network address

The manufacturer shall provide a minimum of eight hours of on-site training for the Owner's operating personnel, covering routine operation, the operator interface, alarm response, common maintenance tasks, and refrigerant management requirements. Training shall be scheduled during the substantial completion period when permanent operating personnel are available.

Chillers shall be set on housekeeping pads designed per Concrete PadsThis citation does not resolve.syncs/concrete-pads sized for the operating weight of the chiller, including a full water charge in the evaporator and condenser (water-cooled). The pad shall extend a minimum of 4 in. beyond the chiller footprint on all sides and shall be a minimum of 4 in. above the surrounding floor for drainage and access. Anchor bolts shall be set per the chiller manufacturer's foundation drawing; embedment and bolt size shall be adequate for the operating, wind, and seismic loads where applicable.

For roof-mounted air-cooled chillers, the structural support shall be designed by the structural engineer for the operating weight, the wind loads on the chiller as an exposed structure, the seismic loads, and the dynamic load from condenser fan operation. The Contractor shall provide the actual operating and shipping weights to the structural engineer at the chiller selection stage.

Tube pull clearance is the single most frequently violated chiller service clearance — the dimension is large (frequently equal to the full evaporator length, often 8 ft to 15 ft) and is required at the end of the chiller opposite the water connections. Installations that omit tube pull clearance commit the building to either cutting tubes in place during retubing or relocating equipment to gain access. Coordinate with the architectural and structural drawings at the design stage; tube pull clearance shall not be sacrificed to fit additional equipment in the room.

For air-cooled chillers, condenser air intake and discharge clearances per the manufacturer's installation manual shall be maintained on all sides. Failure to maintain these clearances causes condenser air recirculation, which substantially raises the effective condensing temperature and degrades capacity and efficiency at peak ambient conditions.

Chilled water and condenser water piping shall be connected to the chiller per Hydronic PipingThis citation does not resolve.syncs/hydronic-piping. Pipe size at the chiller shall match the connection size; reductions or expansions in piping shall be made away from the chiller, not at the connection. Flexible connectors shall be provided at both connections to accommodate small misalignments and isolate piping vibration. Isolation valves shall be installed in both connections to permit chiller service without draining the system, and drain valves shall be installed between the isolation valves and the chiller to allow the chiller water side to be drained without disturbing the rest of the system.

The refrigerant relief vent piping shall be installed from the chiller relief device(s) to outdoors per ASHRAE 15. The vent line shall be sized so that the back-pressure on the relief device does not exceed the manufacturer's allowable value, shall be supported independently of the chiller, and shall terminate at a location where a refrigerant release will not be drawn into a building outdoor air intake. The terminal shall be provided with a turned-down elbow or weatherproof cap that prevents rain ingress but does not impede flow.

Chilled water piping connected to the chiller shall be insulated continuously with vapor-tight insulation per Hydronic PipingThis citation does not resolve.syncs/hydronic-piping. Insulation shall be continuous over flanges, valves, and fittings to prevent condensation, and the vapor barrier shall be continuous and sealed. Discontinuities in chilled water insulation produce condensation that damages floors, ceilings, and adjacent equipment and is one of the most common warranty-period complaints on new chiller installations.

The Owner is responsible for ongoing refrigerant management under 40 CFR Part 82. The Contractor's responsibilities under this standard are to:

• Document the refrigerant type, total system charge weight, and date of charge on the chiller's nameplate and in the closeout submittals
• Ensure that any field refrigerant addition is performed only by EPA Section 608 certified technicians
• Provide refrigerant recovery during any major service that opens the refrigerant circuit; venting of refrigerant to atmosphere is prohibited under EPA rules and constitutes a federal violation
• Provide the Owner with the refrigerant management documentation, the recommended leak inspection interval, and the manufacturer's leak rate threshold for triggering corrective action

Chillers shall be shipped in the manufacturer's standard shipping configuration with all openings sealed with manufacturer-supplied protective covers, the refrigerant circuit either charged or under a nitrogen holding charge, and the water sides either dry or with a corrosion inhibitor. The Contractor shall inspect packaging upon delivery for damage, photograph any damage, and notify the manufacturer before accepting the shipment.

Where storage will exceed three months before startup, the manufacturer's long-term storage procedure shall be followed. This typically includes maintaining the nitrogen holding charge above atmospheric pressure (to prevent moisture ingress), rotating the compressor by hand at the manufacturer's specified interval, energizing oil heaters where the compressor is in a humid environment, and periodically replacing desiccant in the refrigerant circuit.

Rigging and lifting shall use only the manufacturer's designated lift points. Lifting by piping connections, by the control panel, or by improperly placed straps risks damaging the casing, distorting the shells, or unbalancing the rigged load. The manufacturer's rigging diagram shall be available at the rigging location and shall be reviewed before any rigging activity.

The warranty shall cover defects in materials and workmanship under normal use and service conditions for the specified period. Standard manufacturer warranty for chillers is one year parts and labor with an additional four years on the compressor (frequently described as "1+4" or "5-year compressor"); this reflects the relative cost and complexity of compressor repair compared to other components. Extended warranties to two, three, or five years on the complete chiller are available at additional cost and may be justified for critical installations.

Warranty shall not apply to damage caused by: operation outside the design conditions, operation with water chemistry outside the limits established by HVAC Water TreatmentThis citation does not resolve.syncs/hvac-water-treatment, operation without functional flow switches or freeze protection, lack of the manufacturer's specified annual maintenance, field-installed refrigerant of incorrect type or quality, or installation contrary to the manufacturer's published installation instructions.

Spare parts shall be provided at substantial completion as follows. Spare parts shall be packaged for long-term storage and clearly labeled with the chiller tag, model, and serial number.

Filter-driers, oil filters, and gaskets are routine maintenance consumables that shall be on hand for the first scheduled service. A spare condenser fan motor is justified for air-cooled chillers because a fan motor failure can substantially reduce capacity until the motor is replaced and fan motors are sometimes long-lead items. A spare control board is justified only for critical installations because the boards are expensive and prone to fail individually rather than predictably across a fleet.