1 Scope

NOTE This standard covers the equipment, accessories, integral controls, ignition and flame-safety systems, vent and combustion-air interface, fuel-gas connection at the furnace, condensate handling, electrical connection, installation, startup, and testing of gas-fired warm-air central furnaces used as primary heating equipment. (1.1)

NOTE The scope of this standard begins at the furnace's gas-valve inlet, electrical disconnect, and return-air connection, and terminates at the supply-air plenum connection, the vent connector, and the condensate drain stub-out. (1.2)

NOTE This standard applies to furnaces rated up to 225,000 Btu/hr input. At or above 225,000 Btu/hr input, a furnace is a DOE "commercial warm air furnace" governed by 10 CFR 431.77 (thermal-efficiency basis) rather than the AFUE basis used here, and is outside this standard's scope. (1.3)

1.4 Furnace selection, capacity, quantity, location, airflow configuration, and zoning are as indicated on the mechanical equipment schedules and mechanical floor plans.

NOTE This standard establishes the materials, performance, efficiency, controls, and installation requirements that govern those drawings. (1.5)

1.6 Fuel-gas piping, pressure regulation, and LP storage upstream of the furnace gas valve shall be coordinated with this standard at the furnace inlet.

NOTE Fuel-gas piping, pressure regulation, and LP storage upstream of the furnace gas valve are the subject of Fuel Gas PipingFacility Liquefied-Petroleum and Fuel Gas PipingResolves to the current edition.sync/fuel-gas-piping. (1.6.1)

NOTE Ductwork, plenums, registers, and duct-mounted accessories downstream of the furnace are the subject of HVAC DuctworkHVAC DuctworkResolves to the current edition.sync/hvac-ductwork and Duct AccessoriesHVAC Duct AccessoriesResolves to the current edition.sync/duct-accessories; this standard governs only the furnace's external static-pressure rating and listed plenum clearances. (1.7)

NOTE Where a furnace is matched with an evaporator coil for summer cooling, the cooling equipment is the subject of Condensing UnitsAir-Cooled Condensing UnitsResolves to the current edition.sync/condensing-units and Split System Air ConditionersSplit-System Air Conditioners and Heat PumpsResolves to the current edition.sync/split-system-air-conditioners; this standard governs the furnace cabinet, the coil-cabinet interface, and the airflow required for the cooling mode. (1.8)

2 Referenced Standards

2.1 Equipment, accessories, 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.

2.3 The applicable mechanical code and the applicable fuel-gas code (NFPA 54 / IFGC as adopted by the jurisdiction) shall take precedence over all other references on any matter directly addressed by those codes.

Standard	Title
ANSI Z21.47 / CSA 2.3 (2021)	Gas-Fired Central Furnaces
UL 1995 / CSA C22.2 No. 236	Heating and Cooling Equipment
NFPA 54 / ANSI Z223.1	National Fuel Gas Code
IFGC	International Fuel Gas Code (Chapter 5, vent sizing)
NFPA 70	National Electrical Code (Article 424 for supplemental electric heat)
ANSI/ASHRAE/IES 90.1	Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings (Table 6.8 heating minimums)
ASHRAE Standard 103	Methods of Testing for Annual Fuel Utilization Efficiency of Residential Central Furnaces and Boilers
10 CFR Part 430 Subpart B	DOE Energy Conservation Standards for Consumer Furnaces (AFUE)
10 CFR Part 431.77	DOE Energy Conservation Standards for Commercial Warm Air Furnaces (thermal efficiency; equipment at or above 225,000 Btu/hr)
ACCA Manual J / Manual N	Residential and Commercial Load Calculation
ACCA Manual S	Residential Equipment Selection
ACCA Manual D	Residential Duct Systems
AHRI 210/240	Performance Rating of Unitary Air-Conditioning and Air-Source Heat Pump Equipment (matched furnace/coil systems)
SMACNA HVAC Duct Construction Standards	HVAC Duct Construction Standards — Metal and Flexible
ENERGY STAR	Program Requirements for Central Gas Furnaces (95% AFUE minimum, gas)

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following for the Engineer's review prior to procurement and installation.

3.1.2 Work shall not proceed on any furnace until the corresponding submittals have been reviewed and returned.

Product data for each furnace, indicating manufacturer, model number, airflow configuration (upflow, downflow, horizontal-left, horizontal-right), fuel type (natural gas or LP), input and output rating (Btu/hr), AFUE or thermal efficiency, vent category (I, III, or IV), permitted vent material and maximum equivalent vent length, ignition type, burner staging, external static-pressure rating, listed temperature-rise range, blower motor type and horsepower, electrical characteristics, and applicable certification listings (ANSI Z21.47 / CSA 2.3, UL 1995)
Manufacturer's certified ratings establishing compliance with the project efficiency floor (ASHRAE 90.1 Table 6.8 or the specified ENERGY STAR level), with AFUE or thermal efficiency stated at the rated firing condition
Equipment selection calculations demonstrating that furnace input is sized to the ACCA Manual J / Manual N design heat-loss load within the limits of this standard, including any high-altitude de-rate applied at the installed elevation
Fan-performance data and blower-speed table showing available external static pressure across the operating airflow range, with the selected heating and cooling airflow and the resulting temperature rise within the listed min-max range
Venting and combustion-air plan for each furnace, including vent category, vent material and diameter, total equivalent vent length, intake and exhaust termination locations and clearances, common-venting calculations where furnaces share a vent, and condensate routing for Category IV equipment
Fuel-gas connection details, including required inlet pressure at the furnace, manifold pressure, gas-train components (manual shutoff, sediment trap, union), and any second-stage regulator required where the gas service is delivered at elevated pressure, coordinated with Fuel Gas PipingFacility Liquefied-Petroleum and Fuel Gas PipingResolves to the current edition.sync/fuel-gas-piping
Electrical connection details, including circuit ampacity, overcurrent protection, disconnect location and rating, and equipment grounding and bonding coordinated with Grounding And BondingGrounding and Bonding for Electrical SystemsResolves to the current edition.sync/grounding-and-bonding
Controls interface description, identifying whether the furnace control board interfaces with the thermostat only or with the building automation system, and the interface type (24 VAC hardwired contacts, 0-10 VDC, or communicating protocol), coordinated with HVAC Controls InstrumentationHVAC Instrumentation and Control DevicesResolves to the current edition.sync/hvac-controls-instrumentation and Building Automation SystemBuilding Automation SystemResolves to the current edition.sync/building-automation-system
Coil-cabinet and matched-coil data where the furnace is paired with cooling, including AHRI 210/240 matched-system ratings, coil airflow, and condensate-drain provisions
Filter data, including filter type, dimensions, MERV rating, and the rack or cabinet arrangement
Manufacturer's installation, operation, and maintenance instructions and the startup / commissioning checklist
LP conversion kit data and qualified-installer certification where the furnace is field-converted to propane

Action Submittals Requiredcheckbox

☑ Furnace product data (configuration, fuel, input/output, efficiency, vent category)

☐ Certified efficiency ratings vs. project floor

☐ Equipment selection / load-match calculations (incl. altitude de-rate)

☐ Fan-performance and blower-speed table with temperature rise

☐ Venting and combustion-air plan

☐ Fuel-gas connection details

☐ Electrical connection details

☐ Controls interface description (thermostat vs. BAS)

☐ Coil-cabinet / matched-coil data (AHRI 210/240)

☐ Filter data (type, size, MERV)

☐ Installation/O&M instructions and startup checklist

☐ LP conversion kit and qualified-installer certification

3.2 Closeout Submittals

3.2.1 The Contractor shall submit the following upon completion, before final acceptance.

3.2.2 The Contractor shall submit the completed startup and combustion-analysis report for each furnace.

Completed manufacturer's startup checklist for each furnace, signed and dated
Combustion-analysis report for each furnace recording measured carbon monoxide (air-free), flue-gas temperature, manifold gas pressure, and inlet gas pressure at the firing condition
Measured external static pressure and supply-air temperature rise for each furnace, confirming the rise falls within the listed range
Record drawings showing the as-installed furnace locations, vent routing and terminations, and condensate routing
Operation and maintenance manuals, including filter type and replacement schedule, ignition and limit-control adjustment, and seasonal startup and shutdown procedures
Warranty documentation for the heat exchanger and the balance of the furnace

Closeout Submittals Requiredcheckbox

☑ Signed startup checklist per furnace

☐ Combustion-analysis report (CO air-free, flue temp, gas pressures)

☐ Measured static pressure and temperature rise per furnace

☐ Record drawings (furnace, vent, condensate)

☐ Operation and maintenance manuals

☐ Heat-exchanger and balance-of-furnace warranty documentation

4 Quality Assurance

4.1 Each furnace shall be listed and labeled by a Nationally Recognized Testing Laboratory to ANSI Z21.47 / CSA 2.3, or to UL 1995 / CSA C22.2 No. 236 where applicable to the equipment category.

4.2 Each furnace shall bear a permanent rating plate stating the input rating, output or heating capacity, AFUE or thermal efficiency, fuel type and manifold pressure, electrical characteristics, vent category, listed clearances to combustibles, and the listed temperature-rise range.

4.3 The installing contractor shall be experienced in the installation and startup of gas-fired warm-air furnaces.

4.4 The installing contractor shall hold any gas-appliance installation license required by the jurisdiction.

4.5 Field conversion between natural gas and propane shall be performed only by personnel qualified by the furnace manufacturer, using the manufacturer's listed conversion kit for the specific model.

4.6 Startup of each furnace shall be performed in accordance with the manufacturer's instructions, including verification of gas pressure, combustion, temperature rise, and operation of all flame-safety and limit controls.

4.7 Furnaces, vent materials, and condensate-handling components shall be the product of a single manufacturer's listed system to the extent the listing requires matched components, and substitution of unlisted vent or condensate components is prohibited.

5 Environmental and Service Conditions

5.1 The design heating load shall be established by an ACCA Manual J (residential) or Manual N (light commercial) calculation.

5.2 Furnace input shall be sized to the calculated design heat-loss load and shall not exceed 125% of that load.

5.3 Furnaces installed above 2,000 ft elevation shall be de-rated for altitude in accordance with the manufacturer's instructions, or furnished with the manufacturer's high-altitude kit.

NOTE Atmospheric and combustion conditions change with elevation; a gas furnace rated at sea level produces less usable output and risks incomplete combustion at altitude unless de-rated, typically on the order of 4% per 1,000 ft above sea level. (5.3.1)

5.3.2 The rated input used for equipment selection shall be the input at the installed elevation, not the sea-level nameplate input.

5.4 The furnace external static-pressure rating shall equal or exceed the design external static pressure of the connected supply-and-return duct system.

NOTE Residential-lineage furnaces are typically rated at 0.5 in. w.g. external static pressure, while light-commercial high-static models are rated at 0.8 in. w.g. to 1.0 in. w.g. (5.4.1)

5.4.2 A residential-rated furnace shall not be applied to a commercial multi-zone duct system whose design external static pressure exceeds the furnace's rating.

5.5 Combustion air shall be provided in accordance with NFPA 54 Chapter 9 for the installed condition (confined space, unconfined space, or direct-vent sealed combustion).

NOTE A confined-space installation requires combustion-air openings sized at 1 in.² of free area per 1,000 Btu/hr of total appliance input drawn from outdoors, and an unconfined space requires a room volume of at least 50 ft³ per 1,000 Btu/hr of total input. (5.5.1)

5.5.2 Combustion-air opening sizes and locations shall be shown on the mechanical drawings and shall not be conveyed by general note alone.

5.6 Direct-vent (sealed-combustion) furnaces shall be specified where the mechanical space is of tight construction, is unvented, or cannot provide combustion-air openings by another listed means.

Design External Static Pressurerange

in. w.g.

0.31

Default: 0.5 in. w.g.

Installed Elevation (for altitude de-rate)range

ft

08000

Combustion Air Sourceradio

○ Unconfined space (room volume meets NFPA 54)

● Confined space with outdoor combustion-air openings

○ Direct-vent sealed combustion (concentric or two-pipe)

6 Furnace Type and Configuration

6.1 The furnace airflow configuration shall match the supply-and-return duct arrangement and the furnace location.

NOTE Upflow furnaces draw return air at the bottom and discharge supply air from the top and are the most common commercial arrangement; downflow/counterflow furnaces reverse this for plenums below the floor in slab-on-grade or crawl-space layouts; horizontal furnaces lie on their side for attic and crawl-space installations. (6.1.1)

6.1.2 Where the cooling coil must be located in the supply plenum below the furnace, a downflow configuration shall be specified to provide proper coil drainage and to avoid refrigerant migration.

6.2 The efficiency tier (non-condensing or condensing) shall be selected in coordination with the vent category, condensate handling, and the project efficiency floor.

NOTE Non-condensing furnaces operate in the 80% AFUE range, reject flue gas above its dew point, and vent through Category I or Category III systems; condensing furnaces operate at 90% AFUE and above, recover latent heat by condensing flue gas, and vent through Category IV systems with continuous condensate disposal. (6.2.1)

6.3 The burner staging shall be selected to suit the load profile of the building.

NOTE Single-stage burners fire at one rate; two-stage burners fire at a reduced and a full rate; modulating burners vary firing rate continuously and, paired with an ECM blower, deliver the steadiest supply temperature and the highest seasonal efficiency in variable-load commercial applications. (6.3.1)

6.4 The ignition system shall be a hot-surface igniter or direct-spark electronic ignition. Standing-pilot ignition shall be used only where specifically indicated and permitted by the jurisdiction.

Airflow Configurationradio

● Upflow

○ Downflow / counterflow

○ Horizontal-left

○ Horizontal-right

Efficiency Tierradio

● Condensing (90%+ AFUE, Category IV)

○ Non-condensing (80% AFUE, Category I/III)

Burner Stagingradio

○ Single-stage

● Two-stage

○ Modulating

Ignition Typeradio

● Hot-surface igniter (HSI)

○ Direct-spark ignition

○ Standing pilot (where permitted)

7 Fuel and Capacity

7.1 The furnace shall be furnished and configured for the project fuel type (natural gas or propane).

NOTE The gas valve, burner orifices, and manifold pressure differ between natural gas and propane; a furnace furnished for the wrong fuel, or field-converted with incorrect orifices, produces incomplete combustion, elevated carbon monoxide, or flame rollout. (7.1.1)

7.2 The furnace gas valve shall be sized and configured for the manifold pressure listed for the selected fuel.

NOTE Natural gas manifold pressure is typically 3.5 in. w.c.; propane manifold pressure is typically 10 in. w.c. (7.2.1)

7.3 The required inlet gas pressure at the furnace shall be coordinated with Fuel Gas PipingFacility Liquefied-Petroleum and Fuel Gas PipingResolves to the current edition.sync/fuel-gas-piping and shown on the contract documents.

NOTE Natural gas is typically delivered at the furnace inlet between 5 in. w.c. and 14 in. w.c.; propane is typically delivered between 11 in. w.c. and 14 in. w.c. (7.3.1)

7.3.2 Where the gas service is delivered at elevated pressure (for example 2 psig), a second-stage regulator shall be specified and coordinated so that pressure at the furnace inlet falls within the listed range.

7.4 The furnace input rating shall be selected from the manufacturer's standard offering to match the calculated design load at the installed elevation, within this standard's input range of 40,000 Btu/hr to 225,000 Btu/hr.

Fuel Typeradio

● Natural gas

○ Propane (LP)

Furnace Input Capacityrange

Btu/hr

40000225000

Default: 80000 Btu/hr

Manifold Pressurerange

in. w.c.

311

Default: 3.5 in. w.c.

Required Inlet Gas Pressure at Furnacerange

in. w.c.

514

Default: 7 in. w.c.

8 Efficiency

8.1 Each furnace shall meet or exceed the minimum heating efficiency required by ASHRAE 90.1 Table 6.8 for its capacity category, and shall not be less efficient than the federal minimum AFUE of 80% for non-weatherized gas furnaces.

Minimum AFUErange

%

8098

Default: 80 %

8.2 For new commercial construction in Climate Zones 4 through 8, condensing furnaces of at least 95% AFUE should be specified.

NOTE The DOE northern-climate condensing rule has been subject to legal challenge; ASHRAE 90.1 Table 6.8 and the ENERGY STAR 95% AFUE level are the stable specification levers for driving condensing equipment without relying on the contested federal regional standard. (8.2.1)

8.3 Where ENERGY STAR certification is required by the project, each gas furnace shall be ENERGY STAR certified at no less than 95% AFUE.

ENERGY STAR Certification Requiredradio

○ Yes (95% AFUE minimum)

● No (meet ASHRAE 90.1 minimum)

8.4 The AFUE or thermal efficiency stated on the submittal shall be the certified rating at the furnace's rated firing condition.

NOTE Annual fuel utilization efficiency (AFUE) is established by the ASHRAE 103 test method and applies to furnaces below 225,000 Btu/hr input; thermal efficiency applies to commercial warm-air furnaces at or above that threshold, which are outside this standard. (8.4.1)

9 Cabinet and Heat Exchanger

9.1 The furnace cabinet shall be of galvanized or pre-painted steel with factory-applied internal insulation, and shall provide service access to the burner, heat exchanger, blower, and control compartment.

9.2 The primary heat exchanger shall be the manufacturer's standard for the selected efficiency tier (aluminized or stainless steel for non-condensing; corrosion-resistant stainless steel for the secondary condensing heat exchanger).

NOTE The secondary heat exchanger in a condensing furnace operates continuously in the presence of acidic condensate. (9.2.1)

9.2.2 The secondary heat exchanger in a condensing furnace shall be of a material listed for condensate service.

9.3 The heat exchanger shall be factory-tested for leakage in accordance with ANSI Z21.47.

9.4 The furnace shall not be installed if the heat exchanger shows evidence of cracking, leakage, or corrosion on receipt.

9.5 The blower shall be the type indicated (PSC or ECM); ECM blowers shall be furnished where modulating or variable-capacity operation is specified.

Blower Motor Typeradio

● ECM variable-speed

○ PSC multi-speed

NOTE An ECM (electronically commutated) blower maintains airflow against varying static pressure and consumes less energy at part load, which is why it is paired with two-stage and modulating furnaces. (9.5.1)

9.6 The blower speed shall be set at startup so that the supply-air temperature rise falls within the range listed on the furnace rating plate.

Listed Temperature Rise Rangeselect

35°F to 65°F

40°F to 70°F

45°F to 75°F

50°F to 80°F

NOTE Each furnace lists a minimum and maximum temperature rise (for example 35°F to 65°F, or 45°F to 75°F); operating below the minimum risks condensation in a non-condensing heat exchanger, and operating above the maximum trips the high-limit and shortens heat-exchanger life. (9.6.1)

10 Venting and Condensate

10.1 The vent system shall match the furnace's listed vent category, and the vent material shall be the type listed for that category.

NOTE Category I furnaces vent by gravity or induced draft through Type B vent; Category III positive-pressure non-condensing furnaces vent through listed AL29-4C stainless; Category IV positive-pressure condensing furnaces vent through PVC, CPVC, or polypropylene listed for the furnace. (10.1.1)

10.1.2 A Category IV condensing furnace shall not be vented through a Category I (Type B) vent.

NOTE Installing a condensing furnace on a Type B vent destroys the vent within a single heating season because condensing flue gas attacks the gravity-vent liner; this is a common and severe field error. (10.1.3)

10.2 The vent material, diameter, total equivalent length, and termination shall be specified to match the specific furnace listing and the connected vent run.

10.3 Sidewall and direct-vent terminations shall comply with NFPA 54 clearance requirements, including a minimum of 12 in. above grade and a minimum of 4 ft from building openings such as windows, doors, and air intakes.

10.3.1 Termination clearances shall be shown on the mechanical drawings to prevent field conflict at the building exterior.

10.4 Condensate from a Category IV furnace shall be collected and routed continuously, by gravity or by a listed condensate pump, to a floor drain or to a condensate neutralizer where required by the jurisdiction.

NOTE Condensing-furnace condensate is acidic, with a pH of approximately 3.2 to 5.5, and a typical production of 1.0 to 2.5 gallons per hour per 100,000 Btu/hr of input; a continuously pitched drain line and, where required, an acid neutralizer protect the drainage system. (10.4.1)

10.4.2 A condensate drain line exposed to freezing temperatures shall be protected against freezing, and an outdoor or unconditioned-space drain line shall not be routed where it can freeze and block.

Vent Category and Materialradio

● Category IV — PVC / CPVC / polypropylene (condensing)

○ Category III — AL29-4C stainless (positive-pressure non-condensing)

○ Category I — Type B vent (gravity / induced draft)

Vent Termination Typeradio

● Sidewall (two-pipe or concentric)

○ Vertical through roof

Condensate Disposal (Category IV)radio

● Gravity to floor drain

○ Condensate pump to drain

○ Neutralizer then floor drain

Condensate Neutralizer Requiredradio

● No

○ Yes (per jurisdiction)

11 Controls and Ignition

11.1 The furnace shall be furnished with an integrated control board providing ignition sequencing, blower control, and flame-safety supervision.

11.2 The furnace shall include, at minimum, a flame-sensing or flame-rectification proving circuit, a primary high-temperature limit, a rollout safety switch, and a pressure or airflow proving switch for the induced-draft or power-vent blower.

NOTE These interlocks prove combustion airflow, prove flame, and shut off gas on overtemperature or flame rollout; each is a code-required safety function, not an option. (11.2.1)

11.3 The thermostat or control interface shall match the burner staging and the cooling configuration.

NOTE A single-stage heating-only furnace uses a basic 24 VAC thermostat; two-stage heating with cooling and humidification requires a multi-wire thermostat; modulating and communicating furnaces use a 0-10 VDC or a manufacturer's communicating interface. (11.3.1)

11.4 Where the furnace integrates with the building automation system, the interface method (24 VAC hardwired contacts, 0-10 VDC analog, or communicating protocol) shall be specified before the furnace is ordered and coordinated with HVAC Controls InstrumentationHVAC Instrumentation and Control DevicesResolves to the current edition.sync/hvac-controls-instrumentation and Building Automation SystemBuilding Automation SystemResolves to the current edition.sync/building-automation-system.

Control Interfaceradio

○ 24 VAC thermostat (heating only)

● 24 VAC multi-stage thermostat (heat/cool/HUM)

○ 0-10 VDC analog to BAS

○ Communicating protocol to BAS

NOTE Factory-installed communicating control boards are not standard on all models; specifying the interface late forces field workarounds or re-ordering. (11.4.1)

12 Filters and Cooling-Coil Cabinet

12.1 The furnace shall be furnished with a return-air filter rack or cabinet accepting a filter of the specified type and rating.

12.2 The filter shall be a minimum of MERV 8 unless a higher rating is indicated, and the filter rack shall accept the filter without bypass.

NOTE Filter pressure drop counts against the furnace's available external static pressure; a high-MERV filter on a residential-rated furnace can consume the entire static budget and cause nuisance high-limit trips. (12.2.1)

12.3 Where summer cooling is provided, a matched cooling-coil cabinet shall be furnished and arranged for the airflow configuration, with the coil downstream of the furnace heat exchanger in the supply airstream.

12.4 The matched furnace-and-coil system shall be rated in accordance with AHRI 210/240, and the furnace blower airflow shall meet the coil's rated cooling airflow.

Filter MERV Ratingselect

MERV 8

MERV 11

MERV 13

Cooling-Coil Cabinetradio

● None (heating only)

○ Cased coil furnished with furnace

○ Coil by cooling-equipment supplier (coordinate)

13 Testing

13.1 Each furnace shall be started, tested, and adjusted in accordance with the manufacturer's instructions before the system is placed in service.

13.2 A combustion analysis shall be performed on each furnace at startup.

13.3 The measured air-free carbon monoxide shall not exceed 400 ppm.

13.4 The manifold gas pressure and the inlet gas pressure shall be measured and adjusted to the values listed for the selected fuel.

13.5 The supply-air temperature rise shall be measured and the blower speed adjusted so the rise falls within the listed range.

13.6 The external static pressure shall be measured across the furnace and compared against the furnace rating and the design value.

13.7 The operation of each flame-safety and limit control shall be verified, including flame proving, high-limit trip, rollout switch, and pressure or airflow proving switch.

13.8 Where the furnace is part of a system requiring air balancing, the airflow shall be set and documented under Testing Adjusting And BalancingTesting, Adjusting, and Balancing for HVACResolves to the current edition.sync/testing-adjusting-and-balancing.

Field Tests Requiredcheckbox

☑ Combustion analysis (CO air-free ≤ 400 ppm)

☐ Manifold and inlet gas pressure measured and set

☐ Supply-air temperature rise within listed range

☐ External static pressure measured

☐ Flame-safety and limit controls verified

☐ Airflow balanced and documented

14 Installation

14.1 The furnace shall be installed in accordance with its listing, the manufacturer's instructions, NFPA 54 / IFGC, and NFPA 70.

14.2 The furnace shall be installed with the clearances to combustibles shown on its listing label, and where the furnace is not listed for a clearance, the clearances of NFPA 54 Table 10.2 shall apply.

NOTE Service clearance is required even for a zero-clearance-listed furnace. (14.2.1)

14.2.2 A minimum front service clearance of 24 in. shall be maintained and shall be shown on the mechanical drawings.

14.2.3 The mechanical room or closet shall be dimensioned to include the furnace service clearance, not merely the equipment envelope.

14.3 The furnace shall be set level on a non-combustible base or platform appropriate to the configuration, and a horizontal furnace shall be supported along its length per the manufacturer's instructions.

14.4 The return-air connection shall be made so that no return air is drawn from the combustion zone or the space containing the furnace where prohibited by NFPA 54.

14.5 The supply plenum and ductwork connected to the furnace shall maintain the listed clearance to combustibles, coordinated with HVAC DuctworkHVAC DuctworkResolves to the current edition.sync/hvac-ductwork and the SMACNA HVAC Duct Construction Standards.

14.6 A disconnecting means shall be provided within sight of the furnace in accordance with NFPA 70.

14.7 A gas shutoff valve, sediment trap, and union shall be provided at the furnace in accordance with NFPA 54, coordinated with Fuel Gas PipingFacility Liquefied-Petroleum and Fuel Gas PipingResolves to the current edition.sync/fuel-gas-piping.

14.8 The condensate drain shall be installed with continuous pitch to the point of disposal and shall include the trap or neutralizer required by the furnace listing and the jurisdiction.

Mounting Configurationradio

● Floor-mounted on non-combustible base

○ Suspended / platform-mounted (horizontal)

○ Closet-mounted with clearances

Minimum Front Service Clearancerange

in.

2436

Default: 24 in.

15 Delivery, Storage, and Handling

15.1 Furnaces shall be delivered in the manufacturer's original packaging with the rating plate and installation instructions intact.

15.2 Furnaces shall be stored indoors, upright per the packaging markings, and protected from moisture, dust, and physical damage until installation.

15.3 Furnaces shall be inspected on receipt for shipping damage, and a furnace with a damaged cabinet, heat exchanger, or controls shall not be installed.

16 Warranty

16.1 The manufacturer shall warrant the heat exchanger against defects in materials and workmanship for a minimum of 10 years from the date of substantial completion.

16.2 The manufacturer shall warrant the balance of the furnace against defects in materials and workmanship for a minimum of 5 years from the date of substantial completion.

16.3 The Contractor shall warrant the installation, including venting, gas connection, condensate handling, and electrical connection, for a minimum of 1 year from the date of substantial completion.

Heat-Exchanger Warranty Periodrange

years

1020

Default: 10 years

Balance-of-Furnace Warranty Periodrange

years

510

Default: 5 years

17 Spare Parts

17.1 The Contractor shall furnish one complete set of replacement filters for each furnace, of the specified type and rating.

17.2 The Contractor shall furnish one spare hot-surface igniter or spark electrode for each furnace model installed where electronic ignition is used.

17.3 The Contractor shall furnish one spare flame sensor for each furnace model installed.

Spare Parts to Furnishcheckbox

☑ One set of replacement filters per furnace

☐ One spare igniter / spark electrode per model

☐ One spare flame sensor per model