Use and Care Manual

ManualsBrandsCentury ManualsForced Air FurnacesGUH Series 80% 132000 BTU Input and 107000 BTU Output Natural Gas Hot Air Furnace

507713-01 Page 1 of 32Issue 1623

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.

As with any mechanical equipment, personal injury can

result from contact with sharp sheet metal edges. Be

careful when you handle this equipment.

CAUTION

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

Manufactured By

Comfort-Aire / Century

1900 Wellworth Ave.

Jackson, MI 49203

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

INSTALLATION INSTRUCTIONS

GUH80A

Warm Air Gas Furnace

Upow / Horizontal Left and Right Air Discharge

(P) 507713-01

*P507713-01*

Table of Contents

Unit Dimensions ......................................................................2

GUH80A Gas Furnace.............................................................3

Shipping and Packing List .......................................................3

Safety Information ...................................................................3

Use of Furnace as a Construction Heater ...............................4

General ....................................................................................5

Combustion, Dilution & Ventilation Air .....................................5

Setting Equipment ...................................................................8

Filters ..................................................................................... 11

Duct System ..........................................................................11

Venting...................................................................................12

Gas Piping .............................................................................19

Electrical ................................................................................21

Unit Start-Up ..........................................................................25

Heating Sequence Of Operation ..........................................26

Gas Pressure Adjustment .....................................................26

High Altitude ..........................................................................27

Other Unit Adjustments..........................................................28

Service...................................................................................29

Repair Parts List ....................................................................30

Summary of content (32 pages)

PAGE 1
INSTALLATION INSTRUCTIONS GUH80A Warm Air Gas Furnace Upflow / Horizontal Left and Right Air Discharge 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. WARNING CAUTION Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal injury or loss of life.
PAGE 2
GUH80A Unit Dimensions - inches (mm) NOTE - 5C and 5D size units installed in upflow applications that require air volumes of 1800 cfm (850 L/s or greater must have one of the following: 1. Single side return air with transition, to accommodate 20 x 25 x 1 in. (508 x 635 x 25 mm) air filter. 2. Single side return air with optional RAB Return Air Base 3. Bottom return air. 4. Return air from both sides. 5. Bottom and one side return air. 2 Flue outlet may be horizontal but furnace must be vented vertically.
PAGE 3
GUH80A Gas Furnace The GUH80A gas furnace is shipped ready for installation in the upflow or horizontal right position (for horizontal left position the combustion air pressure switch must be moved). The furnace is shipped with the bottom panel in place. The bottom panel must be removed if the unit is to be installed in horizontal or upflow applications with bottom return air. The furnace is equipped for installation in natural gas applications.
PAGE 4
Temperature Rise NOTE: Furnace must be adjusted to obtain a temperature rise within the range specified on the unit nameplate. Failure to do so may cause erratic limit operation and may result in premature heat exchanger failure. This furnace must be installed so that its electrical components are protected from water.
PAGE 5
General These instructions are intended as a general guide and do not supersede local codes in any way. Consult authorities having jurisdiction before installation. In addition to the requirements outlined previously, the following general recommendations must be considered when installing one of these furnaces: • • • • Place the furnace as close to the center of the air distribution system as possible. The furnace should also be located close to the chimney or vent termination point.
PAGE 6
All gas fired appliances require air for the combustion process. If sufficient combustion air is not available, the furnace or other appliances will operate inefficiently and unsafely. Enough air must be provided to meet the needs of all fuel burning appliances and appliances such as exhaust fans which force air out of the house. When fireplaces, exhaust fans, or clothes dryers are used at the same time as the furnace, much more air is necessary to ensure proper combustion and to prevent a downdraft.
PAGE 7
When ducts are used, they 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 free area, the blocking effect of louvers, grilles, or screens must be considered.
PAGE 8
Setting Equipment Upflow Applications Allow for clearances to combustible materials as indicated on the unit nameplate. Minimum clearances for closet or alcove installations are shown in Figure 8. WARNING Do not install the furnace on its front or its back. Do not connect the return air ducts to the back of the furnace. Doing so will adversely affect the operation of the safety control devices, which could result in personal injury or death.
PAGE 9
Return Air - Upflow Applications Return air can be brought in through the bottom or either side of the furnace installed in an upflow application. If the furnace is installed on a platform with bottom return, make an airtight seal between the bottom of the furnace and the platform to ensure that the furnace operates properly and safely. The furnace is equipped with a removable bottom panel to facilitate installation.
PAGE 10
Removing the Bottom Panel Remove the two screws that secure the bottom cap to the furnace. Pivot the bottom cap down to release the bottom panel. Once the bottom panel has been removed, reinstall the bottom cap. See Figure 11. Removing the Bottom Panel Horizontal Applications The furnace can be installed in horizontal applications. Order horizontal suspension kit (51W10) from Comfort-Aire / Century, or use equivalent suspension method.
PAGE 11
Horizontal Application Unit installed on Platform Table 1 Duct System Use industry approved standards (such as those published by Air Conditioning Contractors of America or American Society of Heating, Refrigerating and Air Conditioning Engineers) to size and install the supply and return air duct system. This will result in a quiet and low static system that has uniform air distribution. Figure 14 NOTE: Do not operate the furnace in the heating mode with an external static pressure that exceeds 0.
PAGE 12
Venting A 4 inch diameter flue transition is factory installed on the combustion air inducer outlet of all models. Figure 16 shows the combustion air inducer as shipped from the factory. Mounting Screws Location 1. Remove the four mounting screws (Figure 15) which secure the combustion air inducer / pressure switch assembly to the orifice plate. Lift the assembly and rotate it 90° clockwise or counter clockwise to either the 3 o’clock position. Resecure with four secrews. Gasket should be left in place. 2.
PAGE 13
Horizontal Position HORIZONTAL LEFT POSITION Top Vent discharge • • HORIZONTAL RIGHT POSITION Top Vent Discharge Disconnect pressure switch hose from barbed fitting on the pressure switch assembly. Remove pressure switch assembly (1 screw) and cut wire tie to free pressure switch wires. Reinstall pressure switch on the other side of orifice plate and reconnect pressure switch hose.
PAGE 14
These series units are classified as fan assisted Category I furnaces when vertically vented according to the latest edition of National Fuel Gas Code (NFPA 54 / ANSI Z223.1) in the USA. A fan assisted Category I furnace is an appliance equipped with an integral mechanical means to either draw or force combustion products through the combustion chamber and/or heat exchanger. This unit is not approved for use with horizontal venting. NOTE: Use these instructions as a guide. They do not supersede local codes.
PAGE 15
Common Venting Using Tile Lined Interior Masonry Chimney and Combined Vent Connector NOTE: Refer to provided venting tables for installations. NOTE: The chimney must be properly sized per provided venting tables or lined with listed metal lining system. Figure 25 DO NOT insulate the space between the liner and the chimney wall with puffed mica or any other loose granular insulating material.
PAGE 16
6. The entire length of single wall metal vent connector shall be readily accessible for inspection, cleaning, and replacement. 7. Single appliance venting configurations with zero lateral lengths (Table 3) are assumed to have no elbows in the vent system. For all other vent configurations, the vent system is assumed to have two 90° elbows.
PAGE 17
Capacity of Type B Double Wall Vents with Type B Double Wall Connectors Serving a Single Category I Appliance NOTE: Single appliance venting configureations with zero lateral lengths are assumed to have no elbows in the vent system. For all other vent configurations, the vent system is assumed to have two 90 ° elbows. For each additional 90° elbow or equivalent (for example two 45° elbows equal one 90° elbow) beyond two, the maximum capacity listed in the venting table should be reduced by 10 percent (0.
PAGE 18
Vent Connector Capacity Type B Double Wall Vents with Type B Double Wall Connectors Serving Two or More Category I Appliances Table 4 Common Vent Capacity Type B Double Wall Vents with Type B Double Wall Connectors Serving Two or More Category I Appliances Table 5 Page 18 of 32 Issue 1623 507713-01
PAGE 19
Removal of the Furnace from Common Vent In the event that an existing furnace is removed from a venting system commonly run with separate gas appliances, the venting system is likely to be too large to properly vent the remaining attached appliances. Conduct the following test while each appliance is operating and the other appliances (which are not operating) remain connected to the common venting system.
PAGE 20
Gas Pipe Capacity - ft³/hr (m³/hr) Note: Capacity given in cubic feet (m³) of gas per hour and based on 06.0 specific gravity gas.
PAGE 21
Leak Check After gas piping is completed, carefully check all piping connections (factory and field installed) for gas leaks. Use a leak detecting solution or other preferred means. NOTE: If emergency shutoff is necessary, shut off the main manual gas valve and disconnect the main power to the furnace. The installer should properly label these devices. The unit is equipped with a field make-up box on the left hand side of the cabinet.
PAGE 22
Before connecting the thermostat, 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 connections to the equipment. Use the provided unit wiring diagram and the field wiring diagram shown in Figure 33. Use 18 gauge wire or larger that is suitable for Class II rating for thermostat connections.
PAGE 23
045-3 070-2 070-3 090-3 090-4 110-3 110-4 110-5 135-5 Wiring Diagram Figure 32 507713-01 Issue 1623 Page 23 of 32
PAGE 24
Integrated Control (Automatic Hot Surface Ignition System) Figure 34 Integrated Control Diagnostic Codes FAILURE CODES NOTE: This control is equipped with a push button switch for diagnostic code recall. The control stores the last 5 fault codes in non-volatile memorty. The most recent fault code is flashed first, the oldest fault code is flashed last. There is a 2 second pause between codes.
PAGE 25
Unit Start-Up 6. Move switch on gas valve to OFF. Do not force. See Figure 35. 7. Wait five 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. FOR YOUR SAFETY READ BEFORE LIGHTING UNIT. WARNING Do not use this furnace if any part have been underwater.
PAGE 26
Heating Sequence Of Operation See figure 36. 1. When thermostat calls for heat, combustion air blower starts. 2. Combustion air pressure switch proves blower operation. Switch is factory set and requires no adjustment. 3. After a 15 second prepurge, the hot surface ignitor energizes. 4. After a 20 second ignitor warm-up period, the gas valve solenoid opens. A 4 second trial for ignition period begins. 5. Gas is ignited, flame sensor proves the flame, and the combustion process continues. 6.
PAGE 27
High Altitude This furnace is carefully designed for optimal performance under a wide range of operating conditions. To ensure proper operation at higher altitudes, certain adjustments and/or kits may be required. Manifold Pressure – Between 2000 and 7500 ft, certain units require manifold pressure adjustments specified in Table 9. Manifold pressure should be measured, and adjusted as required during unit start up. Note: LP/Propane installations require a gas conversion Orifice Kit as specified in Table 10.
PAGE 28
Fan Control The fan on time of 45 seconds is not adjustable. The heat fan off delay (amount of time that the blower operates after the heat demand has been satisfied) may be adjusted by changing the jumper position across the five pins on the integrated control. The unit is shipped with a factory fan off delay setting of 90 seconds. The fan off delay affects comfort and is adjustable to satisfy individual applications.
PAGE 29
Service Filters Filters are installed external to the unit. Filters should be inspected monthly. Clean or replace the filters when necessary to ensure that the furnace operates properly. Replacement filters must be rated for high velocity airflow. Table 1 lists recommended filter sizes. WARNING ELECTRICAL SHOCK, FIRE, OR EXPLOSION HAZARD. Failure to follow safety warnings exactly could result in dangerous operation, serious injury, death or property damage. Flue And Chimney 1.
PAGE 30
4. To clean burners, run a vacuum cleaner with a soft brush attachment over the face of burners. Visually inspect inside the burners and crossovers for any blockage caused by foreign matter. Remove any blockage. Figure 34 shows burner detail. 5. Reinstall burner box, manifold assembly and burner box cover. 6. Re-install gas supply and turn on electrical pwer to furnace. Repair Parts List The following repair parts are available through independent Comfort-Aire / Century dealers.
PAGE 31
Blower Performance Data Model 045A3 070A2 Upflow / Horizontal 070A3 090B3 090B4 110C4 110C5 135D5 507713-01 Motor Size (hp) 1/3 (4 spd) 1/5 (3 spd) 1/3 (4 spd) 1/3 (4 spd) 1/2 (4 spd) 1/2 (4 spd) 3/4 (4 spd) 3/4 (4 spd) Blower Size 10 x 8 10 x 7 10 x 8 10 x 9 10 x 10 10 x 10 11 x 10 11 x 11 Temp Rise (°F) 15 - 45 40 - 70 30 - 60 35 - 65 30 - 60 30 - 60 30 - 60 30 - 60 CFM @ External Static Pressure - “ w.c. Blower Speed 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.
PAGE 32
REQUIREMENTS for COMMONWEALTH of MASSACHUSETTS Modifications to NFPA-54, Chapter 10 Revise NFPA-54 section 10.8.