COMFORT-AIRE Century GUH96T045B3M, Service Manual

Page 1: ...ee this symbol on labels or in manuals be alert to the potential for personal injury or death Electric shock hazard Can cause injury or death Before attempting to perform any service or maintenance tu...

Page 2: ...age 2nd Stage AFUE ICS Nominal Cooling Capacity tons Gas Inlet in Volts Hertz Phase Min Time Delay Breaker or Fuse Nominal F L A Trans V A Approx Shipping Weight lbs Input Btuh Output Btuh Input Btuh...

Page 3: ...1040 1120 1310 800 945 1100 1245 Norm 830 935 980 1175 720 840 970 1115 30 60 Low Fire 960 1040 1120 1310 1st Stage 625 710 830 950 875 945 995 1195 565 670 760 860 Norm 790 840 920 1080 520 610 685 7...

Page 4: ...idth 68W64 24 5 D Width Night Service Kits 89W50 Two Stage Horizontal Suspension Kit 51W10 80 90 Kit Flush Mount Termination 90 Furnaces only US Only 51W11 2 3 Vent Version Concentric Vent Kit 90 Furn...

Page 5: ...508183 01 Issue 2114 Page 5 of 52 Parts Arrangement Figure 1...

Page 6: ...rnace ignition and ignitor durability The control provides gas ignition safety checks and indoor blower control with two stage gas heating The furnace combustion air inducer gas valve and indoor blowe...

Page 7: ...fies 100 CFM count the flashes and multiply by 100 to determine the actual CFM delivered for example 5 flashes x 100 500 CFM Pin Function 1 Gas Valve Second Stage 2 Second Stage Prove Switch 3 Rollout...

Page 8: ...HUM Humidifier 120VAC Line Input 120VAC XFMR Transformer 120VAC EAC Indoor Air Accessory 120VAC Cool Cool Speed 120VAC Park 1 Dead terminal for alternate speed tap Park 2 Dead terminal for alternate...

Page 9: ...ype bearings MOTOR CONTROLLER J49 J48 Figure 5 GenTeq Blower Motor B3 STATOR WINDINGS OUTPUT SHAFT BEARING ROTOR Figure 6 Blower Motor Components Internal Operation Each time the controller switches a...

Page 10: ...J48 is the power plug Line voltage must be applied to J48 pins 4 and 5 in order for the motor to operate When using 120VAC pins 1 and 2 must be jumpered Jack J49 connects the unit controls to the mot...

Page 11: ...ED HEAT output from controller to motor windings O volts 325VDC One revolution O volts 325VDC O volts 325VDC WINDING 1 WINDING 2 WINDING 3 O volts 325VDC O volts 325VDC O volts 325VDC WINDING 1 WINDIN...

Page 12: ...nit with the burner box front panel in place Each burner uses an orifice that is precisely matched to the burner input Burners can be removed as a one piece assembly for service If burner assembly has...

Page 13: ...183 01 Issue 2114 Page 13 of 52 Intake Air Top Cap Sensor Rollout Switch Rollout Switch Burner Assembly Ignitor Manifold And Gas Orifices Two Stage Gas Valve Burner Box Cover Figure 9 Heating Componen...

Page 14: ...he plug Reading should be between 39 and 70 ohms If the reading is correct then the problem is with the wiring between the jack plug and the control If reading is not correct the issue is the ignitor...

Page 15: ...gative Tap positive Unit Set Point Low Heat Set Point High Heat 045 0 40 0 70 070 0 50 0 85 090 0 50 0 85 110 0 50 0 90 135 0 45 0 90 Table 6 Pressure Switch Setting 0 4500 Pressure Switch Check To ch...

Page 16: ...508183 01 Issue 2114 Page 16 of 52 Black Tubing positive Red and Black or Red Tubing negative Tee 2 long Square Tubing Measuring Device 10 Long Square Tubing Figure 12 Pressure Switch Check...

Page 17: ...is recommended during cooler weather Metal or plastic strapping may be used for vent pipe hangers Uniformly apply a liberal coat of PVC primer for PVC or use a clean dry cloth for ABS to clean inside...

Page 18: ...o end of pipe 7 Immediately after applying last coat of cement to pipe and while both inside socket surface and end of pipe GUH96T VENT PIPE DIA in STANDARD CONCENTRIC Outdoor Exhaust Accelerator Dia...

Page 19: ...heater only FURNACE WATER HEATER OPENINGS To Adjacent Room If the GUH96T furnace replaces a furnace that was commonly vented with another gas appliance the size of the existing vent pipe for that gas...

Page 20: ...orrect the problem Resize the common venting system to the minimum vent pipe size determined by using the appropriate tables in Appendix G These are in the current standards of the National Fuel Gas C...

Page 21: ...ons outdoors 1 Use transition solvent cement or a sheet metal screw to secure the intake pipe to the inlet air connector 2 Route piping to outside of structure Continue with installation following ins...

Page 22: ...the shortest length of 2 PVC pipe possible NOTE Exhaust pipe and intake pipe must be the same diameter TYPICAL INTAKE PIPE CONNECTIONS IN HORIZONTAL DIRECT OR NON DIRECT VENT APPLICATION RIGHT HAND D...

Page 23: ...assistance in sizing vent pipe in these applications NOTE The exhaust collar on all models is sized to accommodate 2 Schedule 40 vent pipe In horizontal applications any transition to exhaust pipe lar...

Page 24: ...tal in exhaust or intake terminations Doing so will cause freeze ups and may block the terminations IMPORTANT Model Min Vent Length All 15 ft or 5 ft plus 2 elbows or 10 ft plus 1 elbow Any approved t...

Page 25: ...21 70 70 48 13 93 92 73 73 69 10 31 16 65 65 43 8 88 87 68 68 64 Standard Termination Elevation 4500 10 000 ft Number of 90 Elbows Used 1 1 2 Pipe 2 Pipe 2 1 2 Pipe 3 Pipe Model Model Model Model 45...

Page 26: ...13 60 60 44 9 76 76 69 69 60 10 23 8 55 55 39 n a 71 71 64 64 55 Concentric Termination Elevation 4 501 10 000 ft Number of 90 Elbows Used 1 1 2 Pipe 2 Pipe 2 1 2 Pipe 3 Pipe Model Model Model Model...

Page 27: ...53 49 10 21 6 50 50 28 68 67 48 48 44 Standard Termination at Elevation 4500 10 000 ft Number of 90 Elbows Used 1 1 2 Pipe 2 Pipe 2 1 2 Pipe 3 Pipe Model Model Model Model 45 70 90 110 135 45 70 90 11...

Page 28: ...tain protective coatings over building materials prolonged exposure to exhaust condensate can destroy protective coatings It is recommended that the exhaust outlet not be located within 6 feet 1 8m of...

Page 29: ...16 16 14 14 23 23 0 to 20 18 to 29 1 1 2 in 8 N A 13 N A N A N A N A N A N A N A 2 in 6 4 12 10 19 16 18 15 N A N A 2 1 2 in N A N A 7 N A 13 N A 12 N A N A N A 3 in N A N A N A N A 8 8 7 7 13 13 1 R...

Page 30: ...52mm for appliances 10 000 pliances 10 000 Btuh 3kw and 50 000 pliances 50 000 Btuh 15kw 6 inches 152mm for appliances 10 000 Btuh 3kw 12 inches 305mm for appliances 10 000 Btuh 3kw and 100 000 Btuh 3...

Page 31: ...let Air Minimum 12 in 305MM above grade or snow accumulation Figure 26 Exiting Exhaust and Intake Vent no common pressure zone 2 Intake and exhaust pipes should be placed as close together as possible...

Page 32: ...OVIDED REDUCER MAY BE REQUIRED TO ADAPT LARGER VENT PIPE SIZE TO TERMINATION 12 305mm INTAKE AIR EXHAUST VENT Figure 29 Direct Vent Concentric Rooftop Termination 71M80 69M29 or 60L46 US 41W92 or 41W9...

Page 33: ...e paved sidewalk or paved driveway located on public property Clearance under veranda porch deck or balcony 12 Equal to or greater than soffit depth 3 feet 9m 12 3 feet 9m within a height 15 feet 4 5m...

Page 34: ...aust pipe size must be done after the final elbow 4 Distance between exhaust pipe terminations on multiple furnaces must meet local codes UNCONDITIONED ATTIC SPACE 3 76MM OR 2 51MM PVC PROVIDE SUPPORT...

Page 35: ...ermination Drain Trap assembled Figure 36 Kit 51W18 USA 15Z70 Canada Parts Identification and Assembly Exhaust from Furnace To Termination Exhaust from Furnace To Termination Kit 51W18 is shown Figure...

Page 36: ...nce above grade or average snow accumulation B Horizontal separation between intake and exhaust C Minimum from end of exhaust to inlet of intake D Exhaust pipe length E Wall support distance from top...

Page 37: ...d end header box Use Teflon tape or appropriate pipe dope NOTE Cold end header box drain plugs are factory installed Check the unused plug for tightness to prevent leakage 3 Install the cap over the c...

Page 38: ...s is not possible a heat cable kit may be used on the condensate trap and line Heating cable kit is available in various lengths 6 ft 1 8m kit no 26K68 24 ft 7 3m kit no 26K69 and 50 ft 15 2m kit no 2...

Page 39: ...tor drain line required Trap at coil is optional Field Provided Vent Figure 46 Furnace with Evaporator Coil Using a Common Drain Unit shown in horizontal left hand discharge position Condensate Drain...

Page 40: ...2 inch PVC Pipe Not Furnished Drain Assembly for 3 4 inch Drain Pipe Condensate Drain Connection In Unit Condensate Drain Connection In Unit Vent To Drain Condensate Drain Connection In Unit Optional...

Page 41: ...w 1 2 inch PVC To Drain 90 Elbow 1 2 inch PVC Not Furnished 1 2 inch PVC Pipe Not Furnished Drain Assembly for 3 4 inch Drain Pipe 90 Street Elbow 1 2 inch PVC Not Furnished Condensate Drain Connectio...

Page 42: ...to move the switch Never use tools If the the switch will not move by hand replace the valve Do not try to repair it Force or attempted repair may result in a fire or explosion Placing the Furnace in...

Page 43: ...mit control to shut the unit off 6 Is gas turned on at the meter 7 Is the manual main shut off valve open 8 Is the internal manual shut off valve open 9 Is the unit ignition system in lockout If the u...

Page 44: ...egulated 1 Connect the test gauge positive side to manifold pressure tap on gas valve as noted above 2 Tee into the gas valve regulator vent hose and connect to test gauge negative 3 Ignite unit on lo...

Page 45: ...01 6500ft 6501 7500ft 7501 10000ft Low Fire High Fire Low Fire High Fire Low Fire High Fire Low Fire High Fire Low Fire High Fire Min Max All Models Natural 1 7 3 5 1 6 3 3 1 5 3 2 1 5 3 1 1 7 3 5 4 5...

Page 46: ...nction of load indicates a poor or partial ground Compare the readings to Table 17 If the readings exceed the maximum shown in Table 17 make repairs before operating the furnace 2 In addition measure...

Page 47: ...____ Temperature Rise ________ SUPPLY AIR Temperatures RETURN AIR Figure 53 Temperature Rise External Static Pressure 1 Tap locations shown in Figure 54 2 Punch a 1 4 diameter hole in supply and retur...

Page 48: ...uced The pressure drop may also cause the limit to trip more frequently during the winter and the indoor coil to freeze in the summer resulting in an increase in the number of service calls Before usi...

Page 49: ...Remove the assembly Keep tubing attached to pressure switches 14 Disconnect the plug from the combustion air inducer Remove two screws which secure combustion air inducer to collector box Remove comb...

Page 50: ...he wires from the gas valve 3 Remove the burner box cover if equipped 4 Disconnect the gas supply line from the gas valve Remove gas valve manifold assembly 5 Mark and disconnect sensor wire from the...

Page 51: ...LACED WITH WIRING MATERIAL HAVING A TEMP RATING OF AT LEAST 90 c 2 PROPER POLARITY MUST BE OBSERVED FOR FIELD LINE VOLTAGE SUPPLY IGNITION CONTROL WILL LOCK OUT IF POLARITY IS REVERSED 3 FOR TEMPORARY...

Page 52: ...r remains energized until the limits are closed Fan On When the thermostat is set for continuous fan operation and there is no demand for heating or cooling a call for fan closes the R to G circuit an...