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507716-01

Page 1 of 58

Issue 1717

INSTALLATION INSTRUCTIONS

GUH95C

Warm Air Gas Furnace

Upflow/Horizontal Left and Right Air Discharge

Save these instructions for future reference

 

(P) 507716-01

*P507716-01*

Manufactured By

Comfort-Aire / Century

1900 Wellworth Ave.

Jackson, MI 49203

This manual must be left with the homeowner for future reference.

This is a safety alert symbol and should never be ignored. When you see this symbol on labels or in 

manuals, be alert to the potential for personal injury or death.

Improper  installation,  adjustment,  alteration,  service 

or maintenance can cause property damage, personal 

injury  or  loss  of  life.  Installation  and  service  must  be 

performed  by  a  licensed  professional  installer  (or 

equivalent), service agency or the gas supplier.

 WARNING

As with any mechanical equipment, personal injury can 

result from contact with sharp sheet metal edges. Be 

careful when you handle this equipment. 

 CAUTION

Table of Contents

Unit Dimensions ..........................................................

2

Parts Arrangement.......................................................

3

Gas Furnace

 ................................................................

4

Shipping and Packing List ...........................................

4

Safety Information .......................................................

4

General ........................................................................

6

Combustion, Dilution & Ventilation Air .........................

6

Installation ...................................................................

9

Filters .........................................................................

13

Duct System ..............................................................

13

Venting Practices .......................................................

16

Condensate Piping ....................................................

34

Gas Piping

 .................................................................

38

Electrical ....................................................................

41

Unit Start-Up ..............................................................

44

Testing for Proper Venting and Sufficient Combustion 

Air for Non-Direct Vent Applications ..........................

48

Other Unit Adjustments..............................................

49

Blower Performance ..................................................

50

Service.......................................................................

52

Planned Service ........................................................

54

Repair Parts List ........................................................

55

Start-Up & Performance Checklist.............................

56

Summary of Contents for GUH95C

Page 1: ...of life Installation and service must be performed by a licensed professional installer or equivalent service agency or the gas supplier WARNING As with any mechanical equipment personal injury can r...

Page 2: ...ir Base 3 Bottom return air 4 Return air from both sides 5 Bottom and one side return air See Blower Performance Tables for additional information 2 Optional External Side Return Air Filter kit is not...

Page 3: ...507716 01 Page 3 of 58 Issue 1717 Figure 1 Parts Arrangement...

Page 4: ...1 Condensate trap cap 1 Condensate trap clamp 1 2 diameter debris screen 1 3 4 Threaded street elbow Check equipment for shipping damage If you find any damage immediately contact the last carrier Pl...

Page 5: ...to prevent operation of either the heating or the cooling unit unless it is in the full HEAT or COOL setting When installed this furnace must be electrically grounded according to local codes In addit...

Page 6: ...ect vent applications do not block the furnace combustion air opening with clothing boxes doors etc Air is needed for proper combustion and safe unit operation When the furnace is installed in an atti...

Page 7: ...bleaches adhesives detergents solvents and other contaminants which can corrode furnace components The requirements for providing air for combustion and ventilation depend largely on whether the furna...

Page 8: ...ey shall be of the same cross sectional area as the free area of the openings to which they connect The minimum dimension of rectangular air ducts shall be no less than 3 inches 75 mm In calculating f...

Page 9: ...rawl Space and Outlet Air to Outside Shipping Bolt Removal Units with 1 2 hp 3 4 hp blower motor are equipped with three flexible legs and one rigid leg The rigid leg is equipped with a shipping bolt...

Page 10: ...cted to or from other heating devices such as a fireplace or stove etc Fire explosion carbon monoxide poisoning personal injury and or property damage could result WARNING Figure 13 Installation Clear...

Page 11: ...nel to facilitate installation Markings are provided on both sides of the furnace cabinet for installations that require side return air Cut the furnace cabinet at the maximum dimensions shown on Page...

Page 12: ...0 mm Maintain a minimum of 24 in 610 mm for front service access An 8 service clearance must be maintained below the unit to provide for servicing of the condensate trap For installations on a combust...

Page 13: ...t is not equipped with a filter or rack Afield provided filter is required for the unit to operate properly Table 1 lists recommended filter sizes A filter must be in place whenever the unit is operat...

Page 14: ...n bonding ABS to either PVC or CPVC Low temperature solvent cement is recommended during cooler weather Metal or plastic strapping may be used for vent pipe hangers Uniformly apply a liberal coat of P...

Page 15: ...ake pipe to the connector if desired Use a drill or self tapping screw to make a pilot hole DANGER OF EXPLOSION Fumes from PVC glue may ignite during system check Allow fumes to dissipate for at least...

Page 16: ...system are not in operation WARNING 1 Seal any unused openings in the common venting system 2 Inspect the venting system for proper size and horizontal pitch Determine that there is no blockage restri...

Page 17: ...d to prevent leakage of combustion products into the living space CAUTION Vent Piping Guidelines This gas furnace can be installed as either a Non Direct Vent or a Direct Vent gas central furnace NOTE...

Page 18: ...plus 2 elbows or 10 ft plus 1 elbow 135 Any approved termination may be added to the minimum length listed This gas furnace must have 3 to 2 reducing elbow supplied or field replacement Canadian kit...

Page 19: ...74 9 36 21 70 55 23 92 92 73 73 69 10 31 16 65 50 18 87 87 68 68 64 Standard Termination at Elevation 4 500 10 000 ft Number of 90 Elbows Used 2nd Pipe 2 1 2 Pipe 3 Pipe Capacity Capacity Capacity 04...

Page 20: ...74 65 9 28 13 60 45 19 76 76 69 69 60 10 23 8 55 40 14 71 71 64 64 55 Concentric Termination Elevation 4500 10 000 ft Number of 90 Elbows Used 2nd Pipe 2 1 2 Pipe 3 Pipe Capacity Capacity Capacity 04...

Page 21: ...3 53 49 10 21 6 50 50 28 68 67 48 48 44 Standard Termination Elevation 4 500 10 000 ft Number of 90 Elbows Used 2 Pipe 2 1 2 Pipe 3 Pipe Capacity Capacity Capacity 045 70 90 110 135 045 70 90 110 135...

Page 22: ...507716 01 Page 22 of 58 Issue 1717 Figure 25 Figure 26...

Page 23: ...ed Follow the next two steps when installing the unit in Direct Vent applications where combustion air is taken from outdoors and flue gases are discharged outdoors The provided air intake screen must...

Page 24: ...ngth must not exceed those listed in Table 5C If 3 diameter pipe is used reduce to 2 diameter pipe at the termination point to accommodate the debris screen 3 Use a sheet metal screw to secure the int...

Page 25: ...on care must be taken to maintain protective coatings over building materials prolonged exposure to exhaust condensate can destroy protective coatings It is recommended that the exhaust outlet not be...

Page 26: ...A 15 N A 22 N A N A N A 3 in N A N A N A N A 10 10 16 16 18 18 1 Refer to 99 Minimum Design Temperature table provided in the current edition of the ASHRAE Fundamentals Handbook 2 Poly Propylene vent...

Page 27: ...ance 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 above the meter regulator assembly 3 feet 9m 6 inches 152mm for ap...

Page 28: ...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 29: ...re 38 2 Intake and exhaust pipes should be placed as close together as possible at termination end refer to illustrations Maximum separation is 3 76 mm on roof terminations and 6 152 mm on sidewall te...

Page 30: ...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 31: ...ping may be equipped with a 90 elbow turndown Using turndown will add 5 feet 1 5 m to the equivalent length of the pipe 8 A multiple furnace installation may use a group of up to four terminations ass...

Page 32: ...NOW ACCUMULATION SIZE PER EXHAUST PIPE TERMINATION SIZE REDUCTION TABLE Figure 46 Non Direct Vent Field Supplied Wall Termination SIZE TERMINATION PER EXHAUST PIPE TERMINATION SIZE REDUCTION TABLE 3 I...

Page 33: ...e To Vent Termination Drain Trap assembled Figure 49 Kit 51W18 Parts Identification and Assembly Exhaust from Furnace To Termination Exhaust from Furnace To Termination Figure 50 Kit 51W18 Trap Assemb...

Page 34: ...Figure 57 and Figure 58 Upflow furnace Figure 53 In upflow furnace applications the field provided vent must be a minimum 1 to a maximum 2 length above the condensate drain outlet connection Any leng...

Page 35: ...ng from furnace must slope down a minimum of 1 4 per ft toward trap Figure 54 Condensate Trap with Optional Overflow Switch When combining the furnace and evaporator coil drains together the A C conde...

Page 36: ...must slope down a minimum of 1 4 per ft toward trap Figure 56 Unit with Cooling Coil Using Separate Drain Figure 57 Evaporator Coil Using a Common Drain Figure 58 Evaporator Coil Using a Common Drain...

Page 37: ...507716 01 Page 37 of 58 Issue 1717 Figure 59 Trap Drain Assembly Using 1 2 PVC or 3 4 PVC...

Page 38: ...ng suitable hangers or straps Install a drip leg in vertical pipe runs to serve as a trap for sediment or condensate 5 A 1 8 N P T plugged tap or pressure post is located on the gas valve to facilitat...

Page 39: ...507716 01 Page 39 of 58 Issue 1717 Figure 61 Gas Piping Upflow Applications Figure 62 Gas Piping Horizontal Applications...

Page 40: ...16 42 530 15 01 490 13 87 460 13 03 430 12 18 400 11 33 1 1 2 38 1 1 610 40 894 2100 59 46 460 41 34 1180 33 41 990 28 03 900 25 48 810 22 94 750 21 24 690 19 54 650 18 41 620 17 56 2 50 8 2 067 52 50...

Page 41: ...t check to make sure the wires will be long enough for servicing at a later date Make sure that thermostat wire is long enough to facilitate future removal of blower for service Complete the wiring co...

Page 42: ...pump refer to the FM21 installation instruction or appropriate dual fuel thermostat instructions Indoor Blower Speeds 1 When the thermostat is set to FAN ON the indoor blower will run continuously on...

Page 43: ...507716 01 Page 43 of 58 Issue 1717 045B E 3 135D E 5 110C E 5 090C E 4 070B E 3 Figure 67 Typical Wiring Diagram...

Page 44: ...r gas Be sure to smell next to the floor because some gas is heavier than air and will settle on the floor The gas valve on the unit is equipped with a gas control switch lever Use only your hand to m...

Page 45: ...e minutes to clear out any gas If you then smell gas STOP Immediately call your gas supplier from a neighbor s phone Follow the gas supplier s instructions If you do not smell gas go to next step 8 Mo...

Page 46: ...Figure 69 Check gas line pressure with unit firing at maximum rate Low pressure may result in erratic operation or underfire High pressure can result in permanent damage to gas valve or overfire On m...

Page 47: ...no adjustment Table 12 Burner Orifice Conversion Kits at Varying Altitudes Capacity 0 7 500 ft 0 2 286m 7 501 10 000 ft 2 286 3 048 m Natural to LP Propane LP Propane to Natural High Altitude Natural...

Page 48: ...2 Visually inspect the venting system for proper size and horizontal pitch Determine there is no blockage or restriction leakage corrosion or other deficiencies which could cause an unsafe condition 3...

Page 49: ...Figure 70 Figure 70 Constant Torque Motor These units are equipped with a constant torque ECM motor It has a DC motor coupled to an electronic control module both contained in the same motor housing...

Page 50: ...20 100 0 10 1360 325 1270 255 1180 205 915 115 865 100 0 20 1310 335 1250 265 1130 215 880 120 815 110 0 30 1275 340 1205 275 1100 225 835 125 775 115 0 40 1250 355 1175 280 1065 230 795 135 730 125 0...

Page 51: ...45 460 1300 395 1050 305 1890 790 1610 575 1425 460 1285 390 1050 295 GUH95C 135 D5 Performance Less Filter External Static Pressure in w c Air Volume Watts at Various Blower Speeds Bottom Return Air...

Page 52: ...to empty condensate water 3 Remove the clean out cap from the condensate trap and empty water Inspect the trap then reinstall the clean out cap Cleaning Heat Exchanger If cleaning the heat exchanger...

Page 53: ...he 2 pin plug to the wire harness 38 Reconnect drain tubes between flue collar and cold end header box 39 Secure burner assembly to vestibule panel using four existing screws Burners are self aligning...

Page 54: ...be repaired or replaced Instruct the homeowners to pay attention to their furnace Situations can arise between annual furnace inspections that may result in unsafe operation For instance items innoce...

Page 55: ...or equivalent service agency or gas supplier Cabinet Parts Upper Access Panel Blower Access Panel Top Cap Control Panel Parts Transformer Integrated Control Board Door Interlock Switch Blower Parts Bl...

Page 56: ...507716 01 Page 56 of 58 Issue 1717 Start Up Performance Checklist...

Page 57: ...C 5 Supply External Static _______ Return External Static ______ Total External Static _______ CONDENSATE LINE 6 Leak Free VENT PIPE 7 Leak Free COOLING MODE INDOOR BLOWER AMPS______ 3 TEMPERATURE DRO...

Page 58: ...height of eight 8 feet above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or equipment The sign shall read in print size no less than...

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