Page 1: Table Of Contents
986TB TWO−STAGE, VARIABLE−SPEED MULTIPOISE CONDENSING GAS FURNACE SERIES A Installation, Start−up, Operating and Service and Maintenance Instructions NOTE: Read the entire instruction manual before starting the installation. SECTION TABLE SAFETY CONSIDERATIONS ......
Page 2 Required Notice for Massachusetts Installations IMPORTANT The Commonwealth of Massachusetts requires compliance with regulation 248 CMR as follows: 5.08: Modifications to NFPA−54, Chapter 10 2) Revise 10.8.3 by adding the following additional requirements: a. For all side wall horizontally vented gas fueled equipment installed in every dwelling, building or structure used in whole or in part for residential purposes, including those owned or operated by the Commonwealth and where the side wall exhaust vent termination is less than seven (7) feet above finished grade in the area of the venting, including but not limited to decks and porches, the following requirements shall be satisfied:...
Page 3: Safety Considerations
SAFETY CONSIDERATIONS CAUTION WARNING CUT HAZARD Failure to follow this caution may result in personal injury. FIRE, EXPLOSION, ELECTRICAL SHOCK, AND CARBON MONOXIDE POISONING HAZARD Sheet metal parts may have sharp edges or burrs. Use care and wear appropriate protective clothing, safety glasses and Failure to follow this warning could result in dangerous gloves when handling parts, and servicing furnaces.
Page 4: Introduction
13. These furnaces SHALL NOT be installed directly on carpet- Natural Gas and Propane Installation Code (NSCNGPIC) CAN/CSA B149.1 ing, combustible tile, or any other combustible material oth- General Installation er than wood flooring. In downflow installations, factory S US: NFGC and the NFPA 90B. For copies, contact the National accessory floor base MUST be used when installed on com- Fire Protection Association Inc., Batterymarch Park, Quincy, bustible materials and wood flooring.
Page 5: Accessories
General 2. Firmly touch the clean, unpainted, metal surface of the fur- nace chassis which is close to the control. Tools held in a These furnaces are shipped with materials to assist in proper person’s hand during grounding will be satisfactorily dis- furnace installation.
Page 6: Loose Parts Bag Contents
WARNING WARNING FIRE, INJURY OR DEATH HAZARD FIRE HAZARD Failure to follow this warning could result in personal Failure to follow this warning could result in personal injury, death and/or property damage. injury, death and/or property damage. When the furnace is installed in a residential garage, the Do not install the furnace on its back or hang furnace with burners and ignition sources must be located at least 18 in.
Page 7 A12267 986TB SHIP WT. LB (KG) FURNACE SIZE CABINET WIDTH OUTLET WIDTH BOTTOM INLET WIDTH AIR INTAKE 42060 140.0 (63.0) 17-1/2 (445) 15-7/8 (403) 16 (406) 8-3/4 (222) 42080 150.0 (67.5) 154.5 (70.2) 60080 21 (533) 19-3/8 (492) 19-1/2 (495) 10-1/2 (267) 164.5 (74.0)
Page 8 THE BLOWER IS LOCATED BELOW THE BURNER SECTION, AND CONDITIONED AIR IS DISCHARGED UPWARD. THE BLOWER IS LOCATED TO THE RIGHT OF THE BURNER SECTION, AND CONDITIONED AIR IS DISCHARGED TO THE LEFT. THE BLOWER IS THE BLOWER IS LOCATED TO THE LEFT LOCATED ABOVE THE OF THE BURNER SECTION, BURNER SECTION, AND...
Page 9: Air For Combustion And Ventilation
AIR FOR COMBUSTION AND WARNING VENTILATION Introduction CARBON MONOXIDE POISONING HAZARD Direct Vent (2−pipe) Applications Failure to follow this warning could result in personal injury or death. When the furnace is installed as a direct vent (2-pipe) furnace, no special provisions for air for combustion are required. However, The operation of exhaust fans, kitchen ventilation fans, other gas appliances installed in the space with the furnace may clothes dryers, attic exhaust fans or fireplaces could create a...
Page 10 Indoor Combustion AirE NFPA & AGA 1. Adjoining rooms can be considered part of a space if: a. There are no closeable doors between rooms. Standard and Known−Air−Infiltration Rate Methods b. Combining spaces on same floor level. Each opening shall Indoor air is permitted for combustion, ventilation, and dilution, if have free area of at least 1 in.
Page 11: Minimum Free Area Required
Table 3 – Minimum Free Area Required for Each Combustion Air Opening or Duct to Outdoors TWO OPENINGS OR TWO HORIZONTAL DUCTS SINGLE DUCT OR OPENING VERTICAL DUCTS (1 SQ. IN./2,000 BTUH) (1 SQ. IN./3,000 BTUH) (1 SQ. IN./4,000 BTUH) FURNACE (1,100 SQ.
Page 12: Condensate Trap
CONDENSATE TRAP Condensate Trap − Upflow Orientation When the furnace is installed in the upflow position, it is not necessary to relocate the condensate trap or associated tubing. Refer to Fig. 8 for upflow condensate trap information. Refer to Condensate Drain section for information how to install the condensate drain.
Page 13 Vent Pipe Clamp Condensate Trap Vent Elbow Clamp Relief Port Collector Box Plugs Vent Elbow Collector Box Plug Condensate Trap Relief Port Condensate Trap Pressure Switch Outlet Port UPFLOW TRAP CONFIGURATION 1 & 2 Stage Units A11307 Fig. 8 − Upflow Trap Configuration (Appearance may vary)
Page 14 Remove pressure switch tube from front pressure switch and discard. A new tube is shipped in the loose parts bag. Remove relief tube from relief Remove tube from relief port. port on condensate trap. Remove the screw that secures the trap to the collector box and remove trap.
Page 15 Remove plug from If alternate vent position collector box. is required, loosen clamp DO NOT DISCARD. on inlet of vent elbow. Remove the screw that secures the trap to the collector box and remove trap. Unconverted Factory Configuration As Viewed in the Horizontal Right Orientation NOTE: Remove knockout in casing before re installing the condensate trap.
Page 16 Remove the screw that secures the condensate trap to the collector box and remove trap. If alternate vent position is required, loosen clamp on vent elbow inlet. Remove relief tube from relief port on condensate trap. Remove front pressure switch tube and discard. A new tube is shipped in the Loose Parts bag.
Page 17: Condensate Drain
CONDENSATE DRAIN CONNECTION c. All condensate piping is at least 3/4-in. PVC and there is a relief tee at the top of condensate drain piping as shown CAUTION below: NOTE: On narrower casings, it may be easier to remove the condensate trap, connect the drain line components and re-install FROZEN AND BURST WATER PIPE HAZARD the condensate trap.
Page 18 6. From the outside of the casing, insert the angled end of the 2. To allow for servicing the trap, the condensate drain elbow Z-pipe through drain hole in the left side of the casing and in the loose parts bag can be used to make a coupler to behind the inducer or gas valve.
Page 19 Evaporator Coil + + + + = Positive pressure < + = Pressure lower than areas with + − = Negative pressure Condensing Furnace Blower creates positive pressure. Positive pressure extends into coil condensate drain (no trap). < + < + <...
Page 20 Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä Evaporator Coil + + + Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä 3/4” PVC Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä...
Page 21: Installation
INSTALL CLAMPS ON DRAIN TUBE ATTACH ELBOW TO ATTACH DRAIN TUBE TO CONDENSATE FORMED END CONDENSATE TRAP DRAIN TRAP OF GROMMET CUT FORMED END OFF PULL DRAIN STUB CONDENSATE DRAIN THROUGH CASING ELBOW CONNECT SHORT END OF ’Z’ PIPE TO MODIFIED DRAIN ELBOW FACTORY SUPPLIED 1/2 IN.
Page 22 Return Air Connections 4. Install special base coil assembly or coil box as shown in in Fig. 20. WARNING NOTE: It is recommended that the perforated supply−air duct flanges be completely removed from furnace when installing the furnace on a factory−supplied cased coil or coil box. To remove the FIRE HAZARD supply−air duct flange, use wide duct pliers or hand seamers to A failure to follow this warning could cause personal injury,...
Page 23 bottom return air is used. To remove bottom closure panel, see Fig. CAUTION 22 or 23. Side Return Air Inlet MINOR PROPERTY HAZARD These furnaces are shipped with bottom closure panel installed in bottom return−air opening. This panel MUST be in place when Failure to follow this caution may result in minor property side return air inlet(s) are used without a bottom return air inlet.
Page 24 best blower electrical efficiency and system airflow performance Provide duct transitions, as required, to smoothly transition airflow occurring with filter pressure drops under 0.1 in. W.C. (25 Pa). from the return duct system to the filter (or IAQ device) to the furnace when the dimensions of the ductwork or furnace return air NOTICE opening do not match the required filter or IAQ device dimensions.
Page 25: Filter Size Information
Table 6 – Filter Media Pressure Drop (Clean) Versus Face Velocity− In. W.C. (Pa) Representative AfterMarket Filter Media* FactoryAccessory Face Velocity Washable Fiberglass* Pleated* (m/s) (1in. / 2.5 cm) (1in. / 2.5 cm) (2in. / 5 cm) (1in. / 2.5 cm) (2in.
Page 26 4-in. 21-in. Furnace Block Off 14-3/16 and 17-1/2-in. Plate Furnace 4-Ton or less, AC capacity airflow 1/2-in. Screws 20-in. Media Cabinet 16-in. Media Cabinet Media Cabinet Installation Media Cabinet Installation Option for Side Return 4-Ton or Less A/C Capacity 21- or 24-1/2-in. 21-in.
Page 27: Opening Dimensions
FURNACE FURNACE (OR COIL CASING WHEN USED) APPROVED COIL ASSEMBLY COIL BOX COMBUSTIBLE COMBUSTIBLE FLOORING FLOORING PLENUM OPENING DOWNFLOW SUBBASE SHEET METAL PLENUM FLOOR SHEET METAL PLENUM OPENING FLOOR FLOOR OPENING OPENING A10491 Fig. 20 − Installation on Combustible Flooring Table 8 –...
Page 28 UPFLOW DOWNFLOW HORIZONTAL PERFORATED DISCHARGE DUCT 90° 90° FLANGE 120° 120° 120° A10493 Fig. 21 − Duct Flanges BOTTOM CLOSURE SCREWS (2) Representative drawing only, SCREWS (4) some models may vary in appearance. Lay furnace on the back or side BOTTOM PLATE Remove the two (2) screws that secure the bottom...
Page 29 5/ 16  (8mm) (8mm) 5/ 16   (44mm)  (44mm) (8mm)  (8mm) 5/ 16  (44mm) 3/ 4  3/ 4  (44mm) A89014 A11037 Fig. 24 − Leveling Legs Fig. 27 − Downflow Return Air Configurations and Restrictions LEVEL 0-IN.
Page 30 COMBUSTION - AIR PIPE (SEE VENTING SECTION) 30 IN. (762 mm) MIN. WORK AREA 2-IN. (51 mm) ROLLOUT PROTECTION REQUIRED Install 12” x 22” (305x559 mm) sheet metal in front of burner compartment area. The sheet metal MUST extend underneath the furnace casing by 1-in. (25 mm) with the door removed.
Page 31: Air Ducts
AIR DUCTS NOTICE Many states, provinces and localities are considering or have implemented standards and/or restrictions on duct sizing practices, ductwork leakage, and/or ductwork thermal, airflow and electrical efficiencies. CONSULT LOCAL CODE OFFICIALS ductwork design performance requirements in your area. General Requirements The duct system should be designed and sized according to accepted national standards such as those published by: Air...
Page 32: Air Delivery Cfm
Table 9 – Cooling and Heating Air Delivery − CFM (Bottom Return with Filter) Unit Size AC/CF Switch Settings External Static Pressure (ESP) SWx3 SWx2 SWx1 42060 AC Default: 1060 1070 1080 1080 1075 1065 1050 1035 1025 1010 CF Default: See note 4 See note 4 See note 4...
Page 33 Table 9 − Cooling and Heating Air Delivery − CFM (Bottom Return with Filter) (Continued) Unit Size AC/CF Switch Settings External Static Pressure (ESP) SWx3 SWx2 SWx1 60080 AC Default: 1745 1755 1755 1760 1755 1750 1745 1725 1705 1685 CF Default: See note 4 See note 4...
Page 34 Table 9 − AC and Heating Air Delivery − CFM (Bottom Return with Filter) (Continued) Unit Size AC/CF Switch Settings External Static Pressure (ESP) SWx3 SWx2 SWx1 66120 AC Default: 1850 1855 1860 1855 1850 1830 1805 1775 1750 1730 CF Default: See note 4 See note 4...
Page 35: Gas Piping
GAS PIPING WARNING WARNING FIRE OR EXPLOSION HAZARD A failure to follow this warning could result in personal FIRE OR EXPLOSION HAZARD injury, death, and/or property damage. Failure to follow this warning could result in personal injury, If local codes allow the use of a flexible gas appliance death, and/or property damage.
Page 36: Electrical Connections
Table 10 – Maximum Capacity of Pipe ELECTRICAL CONNECTIONS NOMINAL LENGTH OF PIPE - FT (M) WARNING IRON PIPE SIZE (3.0) (6.0) (9.1) (12.1) (15.2) IN. (MM) ELECTRICAL SHOCK, FIRE OR EXPLOSION 1/2 (13) HAZARD 3/4 (19) Failure to follow safety warnings could result in 1 ( 25) dangerous operation, serious injury, death or property 1‐1/4 (32)
Page 37 115−V Wiring NOTE: If electrical entry through the furnace top panel is used, a 7/8−in. (22 mm) hole must be drilled through the top panel. Furnace must have a 115-v power supply properly connected and 2. Drill two (2) 1/8−in. (3 mm) pilot holes through the dimples grounded.
Page 38 Accessories 3. Secure power cord to J−Box bracket with a strain relief (See Fig. 36 and 38.) bushing or a connector approved for the type of cord used. 1. Electronic Air Cleaner (EAC) 4. Pull furnace power wires through 1/2−in. (12 mm) diameter Connect an accessory Electronic Air Cleaner (if used) using hole in J−Box.
Page 39: Electrical Data
Table 11 – Electrical Data TWO-STAGE ECM FURNACES UNIT SIZE VOLTS- OPERATING VOLTAGE MAXIMUM UNIT MINIMUM MAXIMUM MAXIMUM HERTZ- RANGE* UNIT AMPACITY# WIRE WIRE FUSE OR CKT PHASE AMPS SIZE LENGTH Maximum* Minimum* FT (M)} AMPS{ 42060 115-60-1 11.5 32 (9.8) 42080 115-60-1 11.5...
Page 40 To HUM Terminal On To Humidifier Leads Furnace Control Board 24 V Coil To Humidifier Leads To Com/24V Screw Terminal on Thermostat Strip A11157 Fig. 36 − Field−supplied Isolation Relay for Humidifiers with Internal Power Supply W/W1 Y/Y2 A11401 Fig. 37 − Typical Two−Stage Field Wiring Diagram...
Page 41 COMMUNICATION CONTINUOUS FAN OUTDOOR SW4 SETUP CONNECTOR (CF) AIRFLOW AIR TEMP SWITCHES SETUP SWITCHES CONNECTOR MODEL PLUG CONNECTOR SW1 SETUP SWITCHES AND BLOWER OFF- DELAY AIR CONDITIONING (A/C) AIRFLOW SETUP SWITCHES HUMIDIFIER TERMINAL (24-VAC 0.5 AMP MAX. ACRDJ – AIR CONDITIONING RELAY DISABLE JUMPER...
Page 42 THERMOSTAT THERMOSTAT See notes 2, 5, 7, 10, 11, 16, and 17 See notes 1, 2, 4, 6, 7, 9, 10, 11, 15, 16, and 17 Modulating and 2-Stage Furnace with Single-Speed Heat Pump Modulating and 2-Stage Furnace with Single-Speed Air Conditioner THERMOSTAT THERMOSTAT See notes 1, 2, 3, 4, 6, 8, 9, 10, 12, 13, 15, 16, and 17...
Page 43: Venting
NOTES FOR THERMOSTAT WIRING DIAGRAMS 1. Heat pump MUST have a high pressure switch for HYBRID HEATr dual fuel applications. 2. Refer to outdoor equipment Installation Instructions for additional information and setup procedure. 3. If the heat pump date code is 1501E or earlier, select the “ZONE” position on the two speed heat pump control. Heat pumps with date code 1601E and later do not have or require a “ZONE”...
Page 44 Other gas appliances with their own venting system may also use WARNING the abandoned chimney as a raceway providing it is permitted by local code, the current edition of the National Fuel Gas Code, and the vent or liner manufacturer’s installation instructions. Care must CARBON MONOXIDE POISONING HAZARD be taken to prevent the exhaust gases from one appliance from Failure to follow the steps outlined below for each appliance...
Page 45: Vent Termination Kit For Direct Vent (2−Pipe) Systems
Table 12 – Vent Termination Kit for Direct Vent (2−pipe) Systems Approved Two−Pipe Termination Fittings Vent and Allowable 1 1/2−in. 2−in. 2 1/2−in. 3−in. 4−in. Combustion Air Concentric Vent (38 mm) (51 mm) (64 mm) (76−mm) (102 mm) Pipe Diameters 1 1/2−in.
Page 46 Ventilated Combustion Air prevailing winds. The roof location is preferred since the vent and combustion air system is less susceptible to damage or The vent pipe for a Ventilated Combustion Air System must contamination. The termination is usually located away from terminate outdoors.
Page 47 The Maximum Vent Length for the vent and combustion air pipe The measured length of pipe used in a single or 2−pipe termination (when used) is determined from the Maximum Equivalent Vent is included in the total vent length. Include deductions from the Length in Table 16 minus the number of fittings multiplied by the Maximum Equivalent Vent Length (MEVL) contained in the deduction for each type of fitting used from Table 17.
Page 48 Combustion Air and Vent Piping Insulation 3. Tighten the clamp around the vent elbow. Torque the clamp to 15 lb−in. See Fig. 45−48. Guidelines Installing the Vent Pipe Adapter and Combustion Air NOTE: Use closed cell, neoprene insulation or equivalent. Pipe Adapter The vent pipe may pass through unconditioned areas.
Page 49 Install the remaining vent and combustion air pipes as shown 15. Handle pipe joints carefully until cement sets. below. It is recommended that all pipes be cut, prepared, and 16. Horizontal portions of the venting system shall be pre−assembled before permanently cementing any joint. supported to prevent sagging.
Page 50 Optional Installation of the Vent Pipe Concentric Vent Single or multiple concentric vent must be installed as shown in NOTE: DO NOT USE THIS TECHNIQUE FOR Fig. 53. Maintain the required separation distance between vents POLYPROPYLENE VENTING SYSTEMS. or pairs of vents as shown in Fig. 53 and all clearance shown in This option provides a disconnect point for the vent pipe.
Page 51: Combustion−Air Vent Pipe, Fitting & Cement Material
3. Slide assembled kit with rain shield REMOVED through 1. Cut two holes, one for each pipe, of appropriate size for hole. pipe size being used. NOTE: Do not allow insulation or other materials to accumulate 2. Loosely install elbow in bracket (if used) and place as- inside of pipe assembly when installing it through hole.
Page 52: Maximum Allowable Exposed Vent Lengths Insulation
Table 15 – Maximum Allowable Exposed Vent Lengths Insulation Table Maximum Allowable Exposed Vent Length in Unconditioned Space − Ft. Unit Size 40,000* BTUH 60,000 BTUH Uninsulated 3/8in. Insulation 1/2in. Insulation Uninsulated 3/8in. Insulation 1/2in. Insulation Pipe Dia. 1 ½ 2 ½...
Page 53 Unit Size 120,000 BTUH 140,000 BTUH Uninsulated 3/8in. Insulation 1/2in. Insulation Uninsulated 3/8in. Insulation 1/2in. Insulation Pipe Dia. 15.2 12.2 22.9 28.9 22.9 32.0 16.7 15.2 19.8 32.0 19.8 38.1 Winter 16.8 13.7 19.8 15.2 19.8 15.2 19.8 18.3 Design 10.7 13.7 13.7...
Page 54: Deductions From Maximum Equivalent Vent Length
ELBOW CONFIGURATIONS VENT TERMINAL CONFIGURATIONS Concentric Long Medium Mitered Standard 2-in., 3-in., or optional 4-in. termination. A13110 Table 17 – Deductions from Maximum Equivalent Vent Length − Ft. (M) Pipe Diameter (in): 11/2 21/2 Mitered 90º Elbow (2.4) (2.4) (2.4) (2.4) (2.4) Medium Radius 90º...
Page 55 Venting System Length Calculations The Total Equivalent Vent Length (TEVL) for EACH combustion air or vent pipe equals the length of the venting system, plus the equivalent length of elbows used in the venting system from Table 17. Standard vent terminations or factory accessory concentric vent terminations count for zero deduction. See vent system manufacturer’s data for equivalent lengths of flexible vent pipe or other termination systems.
Page 56 Attach gaskets to vent pipe and Vent Coupling and Adapter combustion air adapters. A13074 Fig. 40 − Vent Coupling and Adapter with Gaskets TABS ON THE INDUCER OUTLET RESTRICTOR SNAP INTO THE SLOTS AT THE OUTLET OF THE INDUCER FOR USAGE: SEE MAXIMUM EQUIVALENT VENT LENGTH TABLE (10FT.
Page 57 Slope vent pipe back to the furnace at least ¼” per foot Use 45 deg. Elbows where Avoid short horizontal offsets with 90 possible, to ensure conden- deg. Elbows. Short offsets can be sate drainage. difficult to slope and may trap con- densate.
Page 58 Inside Corner Terminations Inside corner vent terminations are permitted provided that: S Only two exterior walls come together to form an angle of 90 degrees to 135 degrees. There are no other exterior walls attached to either wall to form an alcove. S The clearance distances apply when the vent is at least 3 feet (1 meter) from, but not more than 6 feet (2 meters) away from an inside corner.
Page 59 Rotate vent elbow to required position. Any other unused knockout may be used for combustion air connection. Rotate vent elbow to required position. & UPFLOW LEFT CONFIGURATION DOWNFLOW LEFT CONFIGURATION A11309A A11311A Rotate vent elbow to required position. Any other unused Any other unused knockout may be used knockout may be used...
Page 60 ALTERNATE COMBUSTION AIR CONNECTIONS HORIZONTAL LEFT-VERTICAL VENT CONFIGURATION HORIZONTAL RIGHT-VERTICAL VENT CONFIGURATION A11327A A11337 Alternate combustion air connection. Rotate vent elbow to required position. Vent Pipe Requires Internal Vent Kit See Product Data for Current Kit Number HORIZONTAL RIGHT-LEFT VENT CONFIGURATION HORIZONAL LEFT-LEFT VENT CONFIGURATION A11328A A11336...
Page 61 NOTES FOR VENTING OPTIONS 1. Attach vent pipe adapter with gasket to furnace casing. 2. Align notches in rubber coupling over standoffs on adapter. Slide clamps over the coupling. 3. Slide vent pipe through adapter and coupling into vent elbow. 4.
Page 62 A12326 NOTE: The following is based upon National codes for gas appliances and is provided as a reference. Refer to local codes which may supersede these standards and/or recommendations. (1 ) (2 ) Canadian Installations U.S. Installations Item Clearance Description (per CAN/CSA B149.1) (per ANSI Z223.1/NFPA 54) Clearance above grade, veranda, porch, deck, balcony...
Page 63 A12325 NOTE: The following is based upon National codes for gas appliances and is provided as a reference. Refer to local codes which may supersede these standards and/or recommendations. (1 ) (2 ) Canadian Installations U.S. Installations Item Clearance Description (per CAN/CSA B149.1) (per ANSI Z223.1/NFPA 54) Clearance above grade, veranda, porch, deck, balcony or...
Page 64 ¾ in. (222mm) for 3 in. (76mm) ¾ in. (172mm) for 2 in. (51mm) 12 in. (305mm) min. separation between bottom of combustion air and bottom of vent (Typ.) A13305 Fig. 53 − Combustion Air and Vent Pipe Termination for Direct Vent (2−Pipe) System Roof Termination (Preferred) Vent Maintain 12 in...
Page 65 OPTIONAL TERMINATION BRACKET FOR 2-PIPE TERMINATIONS OPTIONAL BRACKET 12-IN. COUPLING (305 MM) 12 IN. (305 MM) SEPARATION BETWEEN BOTTOM OF COMBUSTION AIR AND BOTTOM OF VENT. MAINTAIN 12 IN. (305 MM) CLEARANCE ABOVE HIGHEST ANTICIPATED 12-IN. (305 MM) SNOW LEVEL OR GRADE, ABOVE ANTICIPATED WHICHEVER IS GREATER.
Page 66 Ventilated Combustion Air intake pipe Pipe hangar 3” (76 mm) 12” (305 mm) Ventilated Combustion Air intake termination in crawl space CRAWL SPACE highest level of insulation ATTIC A10497 Fig. 56 − Vent Terminations for Ventilated Combustion Air...
Page 67 EXAMPLE FOR UPFLOW INSTALLATIONS. MAY BE APPLIED TO OTHER CONFIGURATIONS. A12220 Fig. 57 − Sample Inlet Air Pipe Connection for Polypropylene Venting Systems TO CODE−APPROVED DRAIN OR CONDENSATE PUMP Recommend “T” fitting with 4−inch minimum height standpipe (A) of same diameter or larger extending upward. Dry Well Dry Well (water tight...
Page 68: Start−Up, Adjustment, And Safety Check
START−UP, ADJUSTMENT, AND SAFETY 1. Remove blower door. 2. Locate setup switches on furnace control. CHECK 3. Configure the setup switches as necessary for the NOTICE application. 4. Replace blower door. NOTE: If a bypass humidifier is used, setup switch SW1-3 (Low Important Installation and Start−up Procedures Heat Rise Adjust) should be in ON position.
Page 69: Table 21
CAUTION CAUTION UNIT OPERATION HAZARD FURNACE DAMAGE HAZARD Failure to follow this caution may result in intermittent unit Failure to follow this caution may result in reduced furnace operation or performance satisfaction. life. Condensate trap must be PRIMED or proper draining may DO NOT redrill orifices.
Page 70 5. Follow heat value and specific gravity lines to point of WARNING intersection to find orifice size and low−and high−heat manifold pressure settings for proper operation. 6. Check and verify burner orifice size in furnace. NEVER FIRE HAZARD ASSUME ORIFICE SIZE. ALWAYS CHECK AND Failure to follow this warning could result in personal VERIFY.
Page 71 f. Check for gas leaks and verify furnace operation. NOTICE Adjust Temperature Rise NOTE: Blower door must be installed when taking temperature DO NOT set high−heat manifold pressure less than 3.2−in. rise reading. Leaving blower door off will result in incorrect w.c.
Page 72 Adjust Continuous Fan Airflow (and Low-Speed 4. Check the position of setup switch SW1−3. When set to ON, airflow is raised 18% for low heat. Factory default Cooling Airflow) position is OFF. NOTE: When the furnace is used with a 2-speed cooling or heat 5.
Page 73 Checklist 1. Put away tools and instruments. Clean up debris. 2. Verify that switches SW1−1 and SW1−6 are OFF and other setup switches are set as desired. Verify that switches SW1−7 and SW1−8 for the blower OFF DELAY are set as desired per Table 19.
Page 74 A170151 Fig. 63 − Service Label Information...
Page 75 042060 042080 060080 066100 066120 042060 042080 060080 066100 066120 042060 042080 060080 066100 066120 042060 042080 060080 066100 066120 A13216 Fig. 57 − Furnace Setup Switches and Description...
Page 76 Furnace Setup Switch Description SETUP SWITCH SWITCH NAME NORMAL POSITION DESCRIPTION OF USE Turn ON to retrieve up to 7 stored status codes for SW1-1 Status Code Recovery troubleshooting assistance when R thermostat lead is disconnected. When SW1-2 is OFF allows 2-stage operation with a single stage thermostat.
Page 77: Altitude Derate Multiplier For U.s.a
Table 18 – Altitude Derate Multiplier for U.S.A. Table 19 – Blower Off Delay Setup Switch SETUP SWITCH ALTITUDE PERCENT DERATE (SW1-7 AND -8) MULTIPLIER DESIRED HEATING MODE POSITION DERATE FACTOR* BLOWER OFF DELAY (SEC.) 0–2000 0-610 1.00 SW1-7 SW1-8 2001–3000 610-914 0.95...
Page 78: Orifice Size And Manifold Pressure
Table 21 – Orifice Size and Manifold Pressure (In. W.C.) for Gas Input Rate TWO-STAGE FURNACE (TABULATED DATA BASED ON 20,000 BTUH HIGH-HEAT / 13,000 BTUH LOW-HEAT PER BURNER, DERATED 2%/1000 FT (305M) ABOVE SEA LEVEL) ALTITUDE RANGE HEAT VALUE 0.58 0.60 0.62...
Page 79: Service And Maintenance Procedures
Table 19 − Orifice Size and Manifold Pressure (In. W.C.) for Gas Input Rate (Continued) TWO-STAGE FURNACE (TABULATED DATA BASED ON 20,000 BTUH HIGH-HEAT / 13,000 BTUH LOW-HEAT PER BURNER, DERATED 2%/1000 FT (305M) ABOVE SEA LEVEL) ALTITUDE RANGE HEAT VALUE 0.58 0.60 0.62...
Page 80 you must revise your orientation to component location a. Leave 115−v power to furnace turned on. accordingly. b. Look into blower door indicator for current LED status. Electrical Controls and Wiring c. Remove blower door. Each pressure switch is labeled with the reference location (noted NOTE: The Status Codes cannot be retrieved by disconnecting as “COLLECTOR BOX−LPS”...
Page 81 Care and Maintenance 5. Inspect the vent pipe/vent system before each heating sea- son for water leakage, sagging pipes or broken fittings. WARNING Have vent pipes/vent system serviced by a qualified service agency. 6. Inspect any accessories attached to the furnace such as a hu- FIRE OR EXPLOSION HAZARD midifier or electronic air cleaner.
Page 82 3. All factory wires can be left connected, but field thermostat WARNING and accessory wiring may need to be disconnected depend- ing on their length and routing. 4. If the vent and combustion air pipe passes through the ELECTRICAL OPERATION HAZARD blower compartment, it will be necessary to remove the Failure to follow this warning could result in personal injury pipes from the blower compartment.
Page 83 9. Support the manifold and remove the 4 screws that secure 15. Turn gas on at electric switch on gas valve and at external the manifold assembly to the burner assembly and set aside. shut-off or meter Note the location of the green/yellow wire and ground ter- 16.
Page 84 NOTE: The Heat Pad, when used, should be wrapped around the 9. Clean pressure switch port on collect box with a small wire. Shake any water out of pressure switch tube. condensate drain trap. There is no need to use heat tape within the furnace casing.
Page 85 NOTE: Burner cover, manifold, gas valve, and burner assembly 1. Obtain propylene glycol (RV/swimming pool antifreeze or should be removed as one assembly. equivalent). 2. Turn off gas and electrical supplies to your furnace. 7. Clean heat exchanger openings with a vacuum and a soft brush.
Page 86: Sequence Of Operation
BURNER SUPT. ASSY IGNITER BRACKET, IGNITER BURNER ASSY FLAME ROLLOUT SWITCH FLAME SENSOR A11392 Fig. 68 − Priming Condensate Trap (BELOW BURNER) A11403 Fig. 71 − Burner Assembly SEQUENCE OF OPERATION NOTE: Furnace control must be grounded for proper operation or else control will lock out.
Page 87 (1.) If the furnace control CPU selects low−heat opera- from low to high. The high−heat pressure switch relay tion the inducer motor IDM comes up to speed, the HPSR is de−energized to close the NC contact. When suffi- low−heat pressure switch LPS closes, and the fur- cient pressure is available the high−heat pressure switch nace control CPU begins a 15−sec prepurge period.
Page 88 terminal EAC−1 is energized with 115 vac when the high−cooling. The R−to−Y1 circuit starts the outdoor unit on blower motor BLWM is operating. low−cooling speed, and the R−to−G−and−Y1 circuit starts the When the thermostat is satisfied, the R−to−G−and−Y cir- furnace blower motor BLWM at low−cooling airflow which is the cuits are opened.
Page 89 High−cooling airflow is based on the A/C (air condition- When the W/W1 input signal disappears, the furnace con- ing) selection shown in Fig. 64. trol begins a normal inducer post−purge period while chan- ging the blower airflow. If Y/Y2 input is still energized the c.
Page 90 A11326A Fig. 72 − Troubleshooting Guide...
Page 91 A11326B Troubleshooting Guide (Continued)
Page 92 A11326C Troubleshooting Guide (Continued)
Page 93 A13384 Fig. 73 − Wiring Diagram...
Page 94: Parts Replacement Guide
The qualified installer or service agency must use only factory−authorized replacement parts, kits, or accessories when modifying this product. E2017 Bryant Heating & Cooling Systems D 7310 W. Morris St. D Indianapolis, IN 46231 Catalog No. II986TB-07 Edition Date: 10/17 Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.

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