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Comfortmaker F80CTL User Manual
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F80CTL & G80CTL: Instal
lation, Start–Up, Operating and Service and Maintenance
Instructions
Manufacturer reserves the r
ight to change, at any time, specifications and desi
gns without notice and without obligations.
13
A02163
Fig. 18 – Dow
nflow Return
Ai
r Configurations and Res
trictions
A02075
Fig. 19 – Up
flow Return
Ai
r Con
figurations and Restrictions
A02162
Fig. 20 – Horizontal Return
Air Configurations and Restrictio
ns
DOWNFLOW RETURN AIR CONFIGURA
TIONS AND RESTRICTIONS
12
14
Table of Contents
Installation, Start–Up, Operating and Service and Maintenance Instructions
1
A190045
2
Fig. 1 – Dimensional Drawing
2
SAFETY CONSIDERATIONS
3
1. Use only with type of gas approved for this furnace. Refer to the furnace rating plate.
3
2. Install this furnace only in a location and position as specified in the “Location” section of these instructions.
3
3. Provide adequate combustion and ventilation air to the furnace space as specified in “Air for Combustion and Ventilation” section.
3
4. Combustion products must be discharged outdoors. Connect this furnace to an approved vent system only, as specified in the “Venting” section of these instructions.
3
5. Never test for gas leaks with an open flame. Use a commercially available soap solution made specifically for the detection of leaks to check all connections, as specified in the “Gas Piping” section.
3
6. Always install furnace to operate within the furnace’s intended temperature-rise range with a duct system which has an external static pressure within the allowable range, as specified in the “Start-Up, Adjustments, and Safety Check” section...
3
7. When a furnace is installed so that supply ducts carry air circulated by the furnace to areas outside the space containing the furnace, the return air shall also be handled by duct(s) sealed to the furnace casing and terminating outside the space ...
3
8. A gas-fired furnace for installation in a residential garage must be installed as specified in the warning box in the “Location” section.
3
9. The furnace may be used for construction heat provided that the furnace installation and operation complies with the first CAUTION in the LOCATION section of these instructions.
3
10. These Multipoise Gas-Fired Furnaces are CSA (formerly A.G.A. and C.G.A.) design-certified for use with natural and propane gases (see furnace rating plate) and for installation in alcoves, attics, basements, closets, utility rooms, crawlspaces, a...
3
11. See Fig. 2 for required clearances to combustible construction.
3
12. Maintain a 1-in. (25 mm) clearance from combustible materials to supply air ductwork for a distance of 36 in. (914 mm) horizontally from the furnace. See NFPA 90B or local code for further requirements.
3
13. These furnaces SHALL NOT be installed directly on carpeting, tile, or any other combustible material other than wood flooring. In downflow installations, factory accessory floor base MUST be used when installed on combustible materials and wood f...
3
INTRODUCTION
4
A10269
4
Fig. 2 – Clearances to Combustibles
4
A06745
4
Fig. 3 – Return Air Temperature
4
A02054
4
Fig. 4 – Prohibit Installation on Back
4
A93044
4
Fig. 5 – Installation in a Garage
4
CODES AND STANDARDS
4
Safety
4
General Installation
4
Combustion and Ventilation Air
4
Duct Systems
5
Acoustical Lining and Fibrous Glass Duct
5
Gas Piping and Gas Pipe Pressure Testing
5
Electrical Connections
5
Venting
5
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS PROCEDURE
5
1. Disconnect all power to the furnace. Multiple disconnects may be required. DO NOT TOUCH THE CONTROL OR ANY WIRE CONNECTED TO THE CONTROL PRIOR TO DISCHARGING YOUR BODY’S ELECTROSTATIC CHARGE TO GROUND.
5
2. Firmly touch the clean, unpainted, metal surface of the furnace chassis which is close to the control. Tools held in a person’s hand during grounding will be satisfactorily discharged.
5
3. After touching the chassis, you may proceed to service the control or connecting wires as long as you do nothing to recharge your body with static electricity (for example; DO NOT move or shuffle your feet, do not touch ungrounded objects, etc.).
5
4. If you touch ungrounded objects (and recharge your body with static electricity), firmly touch a clean, unpainted metal surface of the furnace again before touching control or wires.
5
5. Use this procedure for installed and uninstalled (ungrounded) furnaces.
5
6. Before removing a new control from its container, discharge your body’s electrostatic charge to ground to protect the control from damage. If the control is to be installed in a furnace, follow items 1 through 4 before bringing the control or yo...
5
7. An ESD service kit (available from commercial sources) may also be used to prevent ESD damage.
5
LOCATION
5
GENERAL
5
A02097
6
Fig. 6 – Multipoise Orientations
6
AIR FOR COMBUSTION AND VENTILATION
6
Minimum dimensions of 3-in. (76 mm).
6
NOTE: Use any of the following combinations of openings: A & B C & D D & E F & G
6
Fig. 7 – Air for Combustion, Ventilation, and Dilution for Outdoors
6
Outdoor Combustion Air Method
6
1. Provide the space with sufficient air for proper combustion, ventilation, and dilution of flue gases using permanent horizontal or vertical duct(s) or opening(s) directly communicating with the outdoors or spaces that freely communicate with the o...
6
2. Fig. 7 illustrates how to provide TWO OUTDOOR OPENINGS, one inlet and one outlet combustion and ventilation air opening, to the outdoors.
6
a. One opening MUST commence within 12 in. (300 mm) of the ceiling and the second opening MUST commence within 12 in. (300 mm) of the floor.
6
b. Size openings and ducts per Fig. 7 and Table 1.
7
c. TWO HORIZONTAL DUCTS require 1 sq. in. (645 sq. mm) of free area per 2,000 Btuh (1,100 mm2/kW) of combined input for all gas appliances in the space per Fig. 7 and Table 1.
7
d. TWO OPENINGS OR VERTICAL DUCTS require 1 sq. in. (645 sq. mm) of free area per 4,000 Btuh (550 mm2/kW) for combined input of all gas appliances in the space per Fig. 7 and Table 1.
7
3. ONE OUTDOOR OPENING requires:
7
a. 1 sq. in. (645 sq. mm) of free area per 3,000 Btuh (734 mm2/kW) for combined input of all gas appliances in the space per Table 1 and
7
b. Not less than the sum of the areas of all vent connectors in the space.
7
Table 1 – Minimum Free Area Required for Each Combustion Air opening of Duct to Outdoors
7
.
7
Table 2 – Minimum Space Volumes for 100% Combustion, Ventilation, and Dilution from Indoors
7
NP = Not Permitted
7
The Standard Method:
7
1. The space has no less volume than 50 cubic feet per 1,000 Btuh of the maximum input ratings for all gas appliances installed in the space and
7
2. The air infiltration rate is not known to be less than 0.40 air changes per hour (ACH).
7
1. Less than 0.40 ACH and
8
2. Equal to or greater than 0.10 ACH
8
1. For other than fan-assisted appliances, such as a draft hood-equipped water heater, use the following equation:
8
A04002
8
2. For fan-assisted appliances such as this furnace, use the following equation:
8
A04003
8
* Minimum opening size is 100 sq in. (64516 sq. mm) with minimum dimensions of 3 in. (76 mm)
8
† Minimum of 3 in. (76 mm) when type-B1 vent is used.
8
A03175
8
Fig. 8 – Air for Combustion, Ventilation, and Dilution from Indoors
8
1. Adjoining rooms can be considered part of a space if:
8
a. There are no closeable doors between rooms.
8
b. Combining spaces on same floor level. Each opening shall have free area of at least 1 in.2/1,000 Btuh (2,000 mm2/kW) of the total input rating of all gas appliances in the space, but not less than 100 in.2 (0.06 m2). One opening shall commence wit...
8
c. Combining space on different floor levels. The volumes of spaces on different floor levels shall be considered as communicating spaces if connected by one or more permanent openings in doors or floors having free area of at least 2 in.2/1,000 Btuh...
8
2. An attic or crawlspace may be considered a space that freely communicates with the outdoors provided there are adequate permanent ventilation openings directly to outdoors having free area of at least 1-in.2/4,000 Btuh of total input rating for al...
8
3. In spaces that use the Indoor Combustion Air Method, infiltration should be adequate to provide air for combustion, permanent ventilation and dilution of flue gases. However, in buildings with unusually tight construction, additional air MUST be p...
8
4. Unusually tight construction is defined as Construction with:
8
a. Walls and ceilings exposed to the outdoors have a continuous, sealed vapor barrier. Openings are gasketed or sealed and
8
b. Doors and openable windows are weatherstripped and
8
c. Other openings are caulked or sealed. These include joints around window and door frames, between sole plates and floors, between wall-ceiling joints, between wall panels, at penetrations for plumbing, electrical and gas lines, etc.
8
Combination of Indoor and Outdoor Air
8
1. Indoor openings shall comply with the Indoor Combustion Air Method below and,
8
2. Outdoor openings shall be located as required in the Outdoor Combustion Air Method mentioned previously and,
8
3. Outdoor openings shall be sized as follows:
8
a. Calculate the Ratio of all Indoor Space volume divided by required volume for Indoor Combustion Air Method below.
8
b. Outdoor opening size reduction Factor is 1 minus the Ratio in a. above.
8
c. Minimum size of Outdoor openings shall be the size required in Outdoor Combustion Air Method above multiplied by reduction Factor in b. above. The minimum dimension of air openings shall be not less than 3 in. (80 mm).
8
INSTALLATION
8
UPFLOW INSTALLATION
8
Bottom Return Air Inlet
8
1. Tilt or raise furnace and remove 2 screws holding bottom filler panel, see Fig. 9.
8
2. Rotate bottom filler panel downward to release holding tabs.
8
3. Remove bottom closure panel.
8
4. Reinstall bottom filler panel and screws.
8
Fig. 9 – Removing Bottom Closure Panel
8
Side Return Air Inlet
9
DOWNFLOW INSTALLATION
9
1. Determine application being installed from Table 3.
9
2. Construct hole in floor, see Table 3 and Fig. 10.
9
3. Construct plenum to dimensions specified, see Table 3 and Fig. 10.
9
4. If downflow subbase is used, install as, see Fig. 11. If coil model numbers END4X, ENW4X or coil casing model number NAEA are used, install as, see Fig. 12.
9
Bottom Return Air Inlet
9
1. Tilt or raise furnace and remove 2 screws holding bottom filler panel, Fig. 9.
9
2. Rotate bottom filler panel downward to release holding tabs.
9
3. Remove bottom closure panel.
9
4. Reinstall bottom filler panel and screws.
9
Fig. 10 – Floor and Plenum Opening Dimensions
9
Fig. 11 – Furnace, Plenum, and Subbase Installed on a Combustible Floor
9
Fig. 12 – Furnace, Plenum, and Coil Assembly or Coil Box Installed on a Combustible Floor
9
HORIZONTAL INSTALLATION
9
Suspended Furnace Support
9
Platform Furnace Support
9
Table 3 – Opening Dimensions - In. (mm)
10
Roll-Out Protection
10
Bottom Return Air Inlet
10
1. Tilt or raise furnace and remove two screws holding bottom filler panel, see Fig. 9.
10
2. Rotate bottom filler panel downward to release holding tabs.
10
3. Remove bottom closure panel.
10
4. Reinstall bottom filler panel and screws.
10
A10164
10
Fig. 13 – Typical Attic Installation
10
Side Return Air Inlet
10
A10130
11
Fig. 14 – Horizontal Unit Suspension
11
A10131
11
Fig. 15 – Horizontal Suspension with Straps
11
FILTER ARRANGEMENT
11
Leveling Legs (If Desired)
11
A89014
11
Fig. 16 – Leveling Legs
11
1. Position furnace on its back. Locate and drill a hole in each bottom corner of furnace, see Fig. 16.
11
2. For each leg, install nut on bolt and then install bolt with nut in hole. (Install flat washer if desired.)
11
3. Install another nut on other side of furnace base. (Install flat washer if desired.)
11
4. Adjust outside nut to provide desired height, and tighten inside nut to secure arrangement.
11
5. Reinstall bottom closure panel if removed.
11
LOCATION RELATIVE TO COOLING EQUIPMENT
11
AIR DUCTS
11
GENERAL REQUIREMENTS
11
Maintain a 1-in. (25 mm) clearance from combustible materials to supply air ductwork for a distance of 36-in. (914 mm) horizontally from the furnace. See NFPA 90B or local code for further requirements
12
Ductwork Acoustical Treatment
12
SUPPLY AIR CONNECTIONS
12
Upflow and Horizontal Furnaces
12
Downflow Furnaces
12
RETURN AIR CONNECTIONS
12
A190346
12
Fig. 17 – Duct Flanges
12
Downflow Furnaces
12
Upflow and Horizontal Furnaces
12
A02163
13
Fig. 18 – Downflow Return Air Configurations and Restrictions
13
A02075
13
Fig. 19 – Upflow Return Air Configurations and Restrictions
13
A02162
13
Fig. 20 – Horizontal Return Air Configurations and Restrictions
13
GAS PIPING
14
1. Gas supply connections MUST be performed by a licensed plumber or gas fitter.
14
2. When flexible connectors are used, the maximum length shall not exceed 36 in. (915 mm).
14
3. When lever handle type manual equipment shutoff valves are used, they shall be T-handle valves.
14
4. The use of copper tubing for gas piping is NOT approved by the state of Massachusetts.
14
Table 4 – Maximum Capacity of Pipe
14
* Cubic ft of gas per hr for gas pressures of 0.5 psig (14-In. W.C.) or less and a pressure drop of 0.5-In. W.C. (based on a 0.60 specific gravity gas). Ref: Table 6 and 9.2 NFGC.
14
Fig. 21 – Redundant Automatic Gas Control Valve
14
Fig. 22 – Burner and Manifold
15
Fig. 23 – Typical Gas Pipe Arrangement
15
ELECTRICAL CONNECTIONS
15
A95236
16
Fig. 24 – Field Wiring Diagram
16
Table 5 – Electrical Data
16
Fig. 25 – Field-Supplied External Electrical Box on Furnace Casing
16
115-V Wiring
16
J-BOX RELOCATION
16
1. Remove and save two screws holding J-Box, see Fig. 26.
16
2. Cut wire tie on loop in furnace wires attached to J-Box.
16
3. Move J-Box to desired location.
16
4. Fasten J-Box to casing with the two screws removed in Step 1.
16
5. Route J-Box wires within furnace away from sharp edges, rotating parts and hot surfaces.
16
A10291
17
Fig. 26 – Relocating J-Box
17
Electrical Connection to J-Box Electrical Box on Furnace Casing Side
17
Fig. 27 – Field-Supplied Electrical Box on Furnace Casing
17
1. Select and remove a hole knockout in the casing where the electrical box is to be installed.
17
2. Remove the desired electrical box hole knockout and position the hole in the electrical box over the hole in the furnace casing.
17
3. Fasten the electrical box to casing by driving two field-supplied screws from inside electrical box into casing steel.
17
4. Remove and save two screws holding J-Box, see Fig. 26.
17
5. Pull furnace power wires out of 1/2-in. (12 mm) diameter hole in J-Box. Do not loosen wires from strain-relief wire-tie on outside of J-Box.
17
6. Route furnace power wires through holes in casing and electrical box and into electrical box.
17
7. Pull field power wires into electrical box.
17
8. Remove cover from furnace J-Box.
17
9. Route field ground wire through holes in electrical box and casing, and into furnace J-Box.
17
10. Reattach furnace J-Box to furnace casing with screws removed in Step 4.
17
11. Secure field ground wire to J-Box green ground screw.
17
12. Complete electrical box wiring and installation. Connect line voltage leads, see Fig. 27. Use best practices (NEC in U.S. for wire bushings, strain relief, etc.
17
13. Reinstall cover to J-Box. Do not pinch wires between cover and bracket.
17
Power Cord Installation in Furnace J-Box
17
1. Remove cover from J-Box.
17
2. Route listed power cord through 7/8-in. (22 mm) diameter hole in J-Box.
17
3. Secure power cord to J-Box bracket with a strain relief bushing or a connector approved for the type of cord used.
17
4. Secure field ground wire to green ground screw on J-Box bracket.
17
5. Connect line voltage leads, see Fig. 24.
17
6. Reinstall cover to J-Box. Do not pinch wires between cover and bracket.
17
BX Cable Installation in Furnace J-Box
17
1. Remove cover from J-Box.
17
2. Route BX cable into 7/8-in. (22 mm) diameter hole in J-Box.
17
3. Secure BX cable to J-Box bracket with connectors approved for the type of cable used.
17
4. Secure field ground wire to green ground screw on J-Box bracket.
17
5. Connect line voltage leads, see Fig. 24.
17
6. Reinstall cover to J-Box. Do not pinch wires between cover and bracket.
17
24-V Wiring
17
ACCESSORIES
17
1. Electronic Air Cleaner (EAC) Connect an accessory Electronic Air Cleaner (if used) using 1/4-in female quick connect terminals to the two male 1/4-in quick-connect terminals on the control board marked EAC-1 and EAC-2. The terminals are rated for ...
17
2. Humidifier (HUM) Connect an accessory 24 VAC, 0.5 amp. maximum humidifier (if used) to the 1/4-in male quick-connect HUM terminal and COM-24V screw terminal on the control board thermostat strip. The HUM terminal is energized when blower is energi...
17
Fig. 28 – Variable Furnace with Single-Speed Air Conditioner
18
Fig. 29 – Variable Furnace with Two-Speed Air Conditioner
18
Fig. 30 – Variable Furnace with Single-Speed Heat Pump (Dual Fuel)
18
Fig. 31 – Variable Furnace with Two-Speed Heat Pump (Dual Fuel)
18
1. Refer to outdoor equipment Installation Instructions for additional information and setup procedure.
18
2. Outdoor Air Temperature Sensor must be attached in all dual fuel applications.
18
3. Refer to ICP thermostat Installation Instructions for additional information and setup procedure.
18
4. When using a Humidity Sensing Thermostat, set DEHUMIDIFY OPTIONS to H DE-ENRGZD FOR DEHUM.
18
5. Optional connection. If wire is connected SW1-2 on VS furnace control should be set in ON position to allow ICP Thermostat to control the furnace staging.
18
6. HUM connection is 24 VAC and is energized when the blower turns on during a call for heat.
18
7. When connecting 115 VAC to humidifier use a separate 115 VAC supply.
18
8. When using a humidifier on a HP installation connect humidifier to hot water.
18
A190154
19
Fig. 32 – Variable Speed Furnace Control for ECM Blower Motor
19
VENTING
19
GENERAL VENTING REQUIREMENTS
19
1. If a vent (common or dedicated) becomes blocked, the furnace will be shut off by the draft safeguard switch located on the vent elbow.
19
2. Two-stage furnaces require Type B vent connectors outside the casing in all configurations. Single wall vent connector may be used inside the furnace casing with the transition to Type B vent outside the furnace casing. Size the connector so that ...
19
3. Do not vent this Category I furnace into a single wall dedicated or common vent. The dedicated or common vent is considered to be the vertical portion of the vent system that terminates outdoors.
19
4. Vent connectors serving Category I furnaces shall not be connected into any portion of a mechanical draft system operating under positive pressure.
19
5. Do not vent this appliance with any solid fuel burning appliance.
19
6. Category I furnaces must be vented vertically or nearly vertically unless equipped with a listed mechanical venter. See SIDEWALL VENTING section.
19
7. Do not vent this appliance into an unlined masonry chimney. (Refer to Chimney Inspection Chart, Fig. 33.
19
1. Seal any unused openings in venting system.
20
2. Inspect the venting system for proper size and horizontal pitch, as required in the National Fuel Gas Code, NFPA 54/ANSI Z223.1 and these instructions. Determine that there is no blockage or restriction, leakage, corrosion and other deficiencies, ...
20
3. As far as practical, close all building doors and windows and all doors between the space in which the appliance(s) connected to the venting system are located and other spaces of the building.
20
4. Close fireplace dampers.
20
5. Turn on clothes dryers and any appliance not connected to the venting system. Turn on any exhaust fans, such as range hoods and bathroom exhausts, so they are operating at maximum speed. Do not operate a summer exhaust fan.
20
6. Follow the lighting instructions. Place the appliance being inspected into operation. Adjust the thermostat so appliance is operating continuously.
20
7. Test for spillage from draft hood equipped appliances at the draft hood relief opening after 5 minutes of main burner operation. Use the flame of a match or candle.
20
8. If improper venting is observed during any of the above tests, the venting system must be corrected in accordance with the National Fuel Gas Code, NFPA 54/ANSI Z223.1.
20
9. After it has been determined that each appliance connected to the venting system properly vents when tested as outlined above, return doors, windows, exhaust fans, fireplace dampers and any other gas-fired burning appliance to their previous condi...
20
Masonry Chimney Requirement
20
Fig. 33 – Chimney Inspection Chart
20
1. Vent connector is Type-B double-wall, and
20
2. This furnace is common vented with at least 1 draft hood equipped appliance, and
20
3. The combined appliance input rating is less than the maximum capacity given in Table 6, and
20
4. The input rating of each space heating appliance is greater than the minimum input rating given in Table 6 for the local 99% Winter Design Temperature. Chimneys having internal areas greater than 38 sq. in. (24516 sq. mm) require furnace input rat...
20
5. The authority having jurisdiction approves.
20
Table 6 – Minimum Allowable Input Rating of Space-Heating Appliance in Thousands of Btuh per Hour
21
a. Shows signs of vent gas condensation, the chimney should be relined in accordance with local codes and the authority having jurisdiction. The chimney should be relined with a listed metal liner, Type-B vent, or a listed chimney adapter kit shall b...
21
b. Indicates the chimney exceeds the maximum permissible size in the tables, the chimney should be rebuilt or relined to conform to the requirements of the equipment being installed and the authority having jurisdiction.
21
EXTERIOR MASONRY CHIMNEY FAN + NAT INSTALLATIONS WITH TYPE-B DOUBLE-WALL VENT CONNECTORS ENFPA & AGA
21
Table 7 – Combined Appliance Maximum Input Rating in Thousands of Btuh per Hour
21
Appliance Application Requirements
21
1. The return-air temperature must be at least 60°F db except for brief periods of time during warm-up from setback at no lower than 55°F (13°C) db or during initial start-up from a standby condition.
21
2. Adjust the gas input rate per the installation instructions. Low gas input rate causes low vent gas temperatures, causing condensation and corrosion in the furnace and/or venting system. Derating is permitted only for altitudes above 2000 Ft. (610 M)
21
3. Adjust the air temperature rise to the midpoint of the rise range or slightly above. Low air temperature rise can cause low vent gas temperature and potential for condensation problems.
21
4. Set the thermostat heat anticipator or cycle rate to reduce short cycling.
21
Additional Venting Requirements
22
1. Attach the single wall vent connector to the furnace vent elbow, and fasten the vent connector to the vent elbow with at least two field-supplied, corrosion-resistant, sheet metal screws located 180° apart.
22
2. Vent the furnace with the appropriate connector, see Fig. 34 - Fig. 46.)
22
3. Determine the correct location of the knockout to be removed.
22
4. Use a hammer and screwdriver to strike a sharp blow between the tie points and work the slug back and forth until the slug breaks free.
22
Sidewall Venting
22
Table 8 – Recommended Minimum Vent Height Per Furnace and Vent Orientation
22
NOTE: All vent configurations must also meet National Fuel Gas Code venting requirements NFGC.
22
Fig. 34 – Upflow Application - Vent Elbow Up
23
Fig. 35 – Downflow Application - Vent Elbow Up then Left
23
Fig. 36 – Upflow Application - Vent Elbow Right
23
Fig. 37 – Downflow Application - Vent Elbow Up
23
Fig. 38 – Horizontal Left Application - Vent Elbow Left
23
Fig. 39 – Downflow Application - Vent Elbow Left then Up
23
Fig. 40 – Downflow Application - Vent Elbow Up then Right
24
Fig. 41 – Horizontal Right Application-Vent Elbow Right
24
Fig. 42 – Horizontal Left Application - Vent Elbow Right then Up
24
Fig. 43 – Horizontal Left Application - Vent Elbow Up
24
Fig. 44 – Horizontal Left Application - Vent Elbow Right
24
Fig. 45 – Horizontal Right Application-Vent Elbow Left
24
Fig. 46 – Horizontal Right Application - Vent Elbow Left then Up
24
Venting Notes for Fig. 34 - Fig. 46
25
1. For common vent, vent connector sizing and vent material: United States use the NFGC.
25
2. Immediately increase to 5-in. (102 mm) or 6-in. (152 mm) vent connector outside furnace casing when 5-in. (127 mm) vent connector is required, refer to Note 1 above.
25
3. Side outlet vent for upflow and downflow installations must use Type B vent immediately after exiting the furnace, except when factory-approved Downflow Vent Guard Kit is used in the downflow position. See Specification Sheet for accessory listing.
25
4. Type-B vent where required, refer to Note 1 above.
25
5. A 4-in.(102 mm) single-wall (26 ga. min.) vent must be used inside furnace casing and when the factory-approved Downflow Vent Guard Kit is used external to the furnace. See Specification Sheet for accessory listing.
25
6. Accessory Downflow Vent Guard Kit required in downflow installations with lower vent configuration. See Specification Sheet for accessory listing.
25
7. Chimney Adapter Kit may be required for exterior masonry chimney applications. Refer to Chimney Adapter Kit for sizing and complete application details. See Specification Sheet for accessory listing.
25
8. Secure vent connector to furnace elbow with (2) corrosion-resistant sheet metal screws, spaced approximately 180° apart.
25
9. Secure all other single wall vent connector joints with (3) corrosion resistant screws spaced approximately 120° apart. Secure Type-B vent connectors per vent connector manufacturer’s recommendations.
25
10. The total height of the vent and connector shall be at least seven feet for the 154,000 Btuh gas input rate model when installed in a downflow application with furnace elbow turned to left side with the connector elbow outside furnace casing poin...
25
START-UP, ADJUSTMENT, AND SAFETY CHECK
25
GENERAL
25
1. Maintain 115-v wiring and ground. Improper polarity will result in status code 10 LED and no furnace operation.
25
2. Make thermostat wire connections at the 24-v terminal block on the furnace control. Failure to make proper connections will result in improper operation, see Fig. 24 - Fig. 32.
25
3. Gas supply pressure to the furnace must be greater than 4.5-In. W.C. (0.16 psig) but not exceed 14-In. W.C. (0.5 psig).
25
4. Check all manual-reset switches for continuity.
25
5. Replace blower compartment door. Door must be in place to operate furnace.
25
6. Setup switch descriptions The variable speed furnace control has DIP switches to select thermostat staging, blower off delay timings, air flow selection and other operational or service related functions, see Fig. 32, Fig. 53 and Table 14.
25
START-UP PROCEDURES
25
1. Purge gas lines after all connections have been made.
25
2. Check gas lines for leaks.
25
3. To Begin Component Self-Test:
25
a. Remove Blower Access Door.
25
b. Disconnect the thermostat R lead from furnace control board.
25
c. Manually close blower door switch.
25
d. Turn Setup DIP switch SW1-6 ON, see Fig. 32, Fig. 53 and Table 14.
25
4. Component test sequence is as follows:
25
a. Inducer motor starts on high-speed and continues to run until Step d. of component test sequence.
25
b. Hot surface igniter is energized for 15 sec., then off.
25
c. Blower motor operates for 15 sec.
25
d. Inducer motor goes to low-speed for 10 sec., then stops.
25
e. After component test is completed, one or more status codes (heartbeat, 2+5) will flash. See component test section of service label (Fig. 49) in furnace for explanation of status codes.
26
5. Turn setup DIP switch SW1-6 OFF. Reconnect R lead to furnace control board, release blower door switch and reinstall blower access door.
26
6. Operate furnace per instruction on inner door.
26
7. Verify furnace shut down by lowering thermostat setting below room temperature.
26
8. Verify furnace restarts by raising thermostat setting above room temperature.
26
ADJUSTMENTS
26
A93059
26
Fig. 47 – Orifice Hole
26
1. Determine the correct gas input rate. The input rating for altitudes above 2,000 ft. (610 M) must be reduced by 4 percent for each 1,000 ft. (305 M) above sea level. For installations below 2000 Ft. (610 M), refer to the unit rating plate. For ins...
26
2. Determine the correct orifice and manifold pressure adjustment. All models in all positions except Low NOx models in downflow and horizontal positions use Table 15 (22,000 Btuh per burner.) Low NOx models in downflow or horizontal positions must u...
26
a. Obtain average yearly gas heat value (at installed altitude) from local gas supplier.
26
b. Obtain average yearly gas specific gravity from local gas supplier.
26
c. Find installation altitude in Table 15 or Table 16.
26
d. Find closest natural gas heat value and specific gravity in Table 15 or Table 16.
26
e. Follow heat value and specific gravity lines to point of intersection to find orifice size and low-and high-heat manifold pressure settings for proper operation.
26
f. Check and verify burner orifice size in furnace. NEVER ASSUME ORIFICE SIZE. ALWAYS CHECK AND VERIFY.
26
g. Replace orifice with correct size, if required by Table 15 or Table 16. Use only factory-supplied orifices. See Example below.
26
* Furnace is shipped with No. 43 orifices. In this example all main burner orifices are the correct size and do not need to be changed to obtain proper input rate.
26
Table 9 – Altitude Derate Multiplier for U.S.A.
26
3. Adjust manifold pressure to obtain low fire input rate, see Fig. 21.
26
a. Turn gas valve ON/OFF switch to OFF.
26
b. Remove manifold pressure tap plug from gas valve.
26
c. Connect a water column manometer or similar device to manifold pressure tap.
26
d. Turn gas valve ON/OFF switch to ON.
26
e. Move setup SW1-2 on furnace control to ON position to lock furnace in low-heat operation, see Table 14 and Fig. 32.
26
f. Manually close blower door switch.
26
g. Jumper R and W/W1 thermostat connections on control to start furnace, see Fig. 32.
26
h. Remove regulator adjustment cap from low heat gas valve pressure regulator (see Fig. 21) and turn low-heat adjusting screw (3/16 or smaller flat-tipped screwdriver) counterclockwise (out) to decrease input rate or clockwise (in) to increase input ...
27
i. Install low-heat regulator adjustment cap.
27
j. Move setup switch SW1-2 to off position after completing low-heat adjustment.
27
k. Leave manometer or similar device connected and proceed to Step 4.
27
4. Adjust manifold pressure to obtain high fire input rate, see Fig. 21.
27
a. Jumper R to W/W1 and W2 thermostat connections on furnace control. This keeps furnace locked in high-heat operation.
27
b. Remove regulator adjustment cap from high-heat gas valve pressure regulator, see Fig. 21, and turn high heat adjusting screw (3/16-in. or smaller flat-tipped screwdriver) counterclockwise (out) to decrease input rate or clockwise (in) to increase ...
27
c. When correct input is obtained, replace caps that conceal gas valve regulator adjustment screws. Main burner flame should be clear blue, almost transparent.
27
d. Remove jumpers R to W/W1 and R to W2.
27
5. Verify natural gas input rate by clocking meter.
27
a. Turn off all other gas appliances and pilots served by the meter.
27
b. Move setup switch SW1-2 to ON position. This keeps furnace locked in low-heat operation.
27
c. Jumper R to W/W1.
27
d. Run furnace for 3 minutes in low-heat operation.
27
e. Measure time (in sec) for gas meter to complete 1 revolution and note reading. The 2 or 5 cubic feet dial provides a more accurate measurement of gas flow.
27
f. Refer to Table 10 for cubic ft. of gas per hr.
27
g. Multiply gas rate cu ft./hr by heating value (Btuh/cu ft.) to obtain input. If clocked rate does not match required input from Step 1, increase manifold pressure to increase input or decrease manifold pressure to decrease input. Repeat steps d thr...
27
h. Move setup switch SW1-2 to OFF position and jumper R to W/W1, and W2. This keeps furnace locked in high-heat operation. Repeat items d through g for high-heat operation.
27
6. Set Temperature Rise.
27
a. Place thermometers in return and supply ducts as near furnace as possible. Be sure thermometers do not see heat exchanger so that radiant heat does not affect readings. This practice is particularly important with straight-run ducts.
27
b. When thermometer readings stabilize, subtract return-air temperature from supply-air temperature to determine air temperature rise.
27
Table 10 – Gas Rate (CU ft./hr)
27
c. This furnace is capable of automatically providing proper airflow to maintain the temperature rise within the range specified on furnace rating plate. If temperature rise is outside this range, proceed as follows:
28
(1.) Check gas input for low- and high-heat operation.
28
(2.) Check derate for altitude if applicable.
28
(3.) Check all return and supply ducts for excessive restrictions causing static pressure greater than 0.5-In. W.C.
28
(4.) Ensure setup switch SW1-4 (Comfort/Efficiency) is in OFF=Efficiency position when a bypass humidifier is used, see Fig. 32 for switch location.)
28
(5.) Make sure proper model plug is installed.
28
d. Remove thermostat jumpers and release blower access door switch.
28
e. Repeat Steps a through c as required to adjust for high heat temperature rise.
28
f. When correct high heat input rate and temperature rise is achieved, turn gas valve ON/OFF switch to OFF.
28
g. Release blower access door switch.
28
h. Remove manometer or similar device from gas valve.
28
i. Re-install manifold pressure tap plug in gas valve, see Fig. 21.
28
j. Remove thermostat jumper wire from furnace control board.
28
k. Turn gas valve ON/OFF switch to ON.
28
l. Proceed to Step 7, “Set Blower Off Delay” before installing blower access door.
28
7. Set Blower Off Delay
28
a. Remove blower access door if installed.
28
b. Turn Dip switch SW-7 or SW-8 ON or OFF for desired blower off delay, see Table 11, Table 14, Fig. 32, and Fig. 53.
28
Table 11 – Blower Off Delay Setup Switch
28
8. Set thermostat heat anticipator.
28
a. Mechanical thermostat. Set thermostat heat anticipator to match the amp. draw of the electrical components in the R-W/W1 circuit. Accurate amp. draw readings can be obtained at the wires normally connected to thermostat subbase terminals, R and W....
28
(1.) Set SW1-2 switch on furnace control board to ON.
28
(2.) Remove thermostat from subbase or from wall.
28
(3.) Connect an amp. meter across the R and W subbase terminals or R and W wires at wall, see Fig. 48.
28
(4.) Record amp. draw across terminals when furnace is in low heat and after blower starts.
28
(5.) Set heat anticipator on thermostat per thermostat instructions and install on subbase or wall.
28
(6.) Turn SW1-2 switch OFF.
28
(7.) Install blower access door.
28
b. Electronic thermostat: Set cycle rate for 3 cycles per hr.
28
9. Set Airflow for Air Conditioning -Single Stage and High Stage Cooling The ECM blower can be adjusted for a range of airflow for Low Speed or High Speed cooling. See Table 13-Air Delivery - CFM (With Filter). Depending on the model size, the coolin...
28
A96316
28
Fig. 48 – Amp. Draw Check with Ammeter
28
Set Airflow For Continuous Fan/Low Speed Cooling Airflow The ECM blower motor can be adjusted for continuous fan speeds different than heating or cooling fan speed. See Table 13 - Air Delivery - CFM (With Filter). Select the required continuous fan a...
28
1. Check Main Limit Switch This control shuts off combustion system and energizes air-circulating blower motor, if furnace overheats. By using this method to check limit control, it can be established that limit is functioning properly and will opera...
28
a. Run furnace for at least 5 minutes.
29
b. Gradually block off return air with a piece of cardboard or sheet metal until the limit trips.
29
c. Unblock return air to permit normal circulation.
29
d. Burners will re-light when furnace cools down.
29
2. Check draft safeguard switch. The purpose of this control is to cause the safe shutdown of the furnace during certain blocked vent conditions.
29
a. Verify vent pipe is cool to the touch.
29
b. Disconnect power to furnace and remove vent connector from furnace vent elbow.
29
c. Restore power to furnace and set room thermostat above room temperature.
29
d. After normal start-up, allow furnace to operate for 2 minutes, then block vent elbow in furnace 80 percent of vent area with a piece of flat sheet metal.
29
e. Furnace should cycle off within 2 minutes. If gas does not shut off within 2 minutes, determine reason draft safeguard switch did not function properly and correct condition.
29
f. Remove blockage from furnace vent elbow.
29
g. Switch will auto-reset when it cools.
29
h. Re-install vent connector.
29
3. Check Pressure Switch(es) This control proves operation of the draft inducer blower.
29
a. Turn off 115-v power to furnace.
29
b. Disconnect inducer motor lead wires from wire harness.
29
c. Turn on 115-v power to furnace.
29
d. Set thermostat to “call for heat” and wait 1 minute. When pressure switch is functioning properly, hot surface igniter should NOT glow and control diagnostic light flashes a status code 3. If hot surface igniter glows when inducer motor is dis...
29
e. Determine reason pressure switch did not function properly and correct condition.
29
f. Turn off 115-v power to furnace.
29
g. Reconnect inducer motor wires, replace outer door, and turn on 115-v power.
29
h. Blower will run for 90 seconds before beginning the call for heat again.
29
i. Furnace should ignite normally.
29
Checklist
29
1. Put away tools and instruments. Clean up debris.
29
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 14.
29
3. Verify that blower and burner access doors are properly installed.
29
4. Cycle test furnace with room thermostat.
29
5. Check operation of accessories per manufacturer’s instructions.
29
6. Review User’s Guide with owner.
29
7. Attach literature packet to furnace.
29
Table 12 – Cooling Airflow Adjustments from 1.5 to 6 Tons
29
X- Indicated an allowable selection.
29
Table 13 – Air Delivery - CFM (With Filter)
30
1. Nominal 350 CFM/ton cooling airflow is delivered with SW1-5 and SW4-3 set to OFF. Set SW1-5 to ON for nominal 400 CFM/ton (+15% airflow). Set SW4-3 to ON for nominal 325 CFM/ton (-7% airflow). Set both SW1-5 and SW4-3 on ON for nominal 370 CFM/ton...
33
2. Maximum cooling airflow is achieved when switches SW2-1, SW2-2, SW2-3 and SW1-5 are set to ON, and SW4-3 is set to OFF.
33
3. All heating CFM's are when comfort/efficiency adjustment switch (SW1-4) is set to OFF
33
4. Ductwork must be sized for high-heating CFM within the operational range of ESP. Operation within the blank areas of the chart is not recommended because high-heat operation will be above 1.0 ESP.
33
5. All airflows on 21" casing size furnaces are 5% less on side return only installations.
33
Table 14 – Furnace Setup Switch Description
34
A190151
34
A190149
34
Fig. 49 – Service Label
34
Table 15 – Orifice Size and Manifold Pressure (In. W.C.) for Gas Input Rate (Tabulated Data Based on 22,000 Btuh High-Heat/14,500 Btuh for Low-Heat per Burner, Derated 4 Percent for Each 1000 Ft. (305 M) Above Sea Level)
35
* Orifice numbers 43 are factory installed
36
Table 16 – Orifice Size and Manifold Pressure (In. W.C.) for Gas Input Rate (Tabulated Data Based on 21,000 Btuh High-Heat/14,500 Btuh for Low-Heat Per Burner, Derated 4 Percent for Each 1000 Ft. (305 M) Above Sea level)
36
* Orifice numbers 43 are factory installed
37
SERVICE AND MAINTENANCE PROCEDURES
37
GENERAL
38
Electrical Controls and Wiring
38
1. To retrieve status codes, proceed with the following:
38
a. Leave 115-v power to furnace turned on.
38
b. Remove outer access door.
38
c. Look into blower access door sight glass for current LED status.
38
d. Remove blower access door.
38
2. Turn Setup Switch, SW1-1 “ON.”
38
3. Manually close blower access door switch.
38
4. Control will flash up to 7 Status Codes.
38
5. The last Status Code, or 8th Code, will be flashing heartbeat.
38
6. Turn SW1-1 “OFF.”
38
7. The Amber LED will flash heartbeat (bright-dim) continuously which indicates proper operation.
38
8. Release blower access door switch, install blower access door and replace outer door, or refer to the SERVICE label on the front of the blower access door for more information.
38
Component Self-Test
38
1. Remove outer access door.
38
2. Remove blower access door.
38
3. Remove the wire from the “R” terminal of the control board.
38
4. Turn Setup Switch, SW-1-6 “ON.”
38
5. Manually close blower access door switch.
38
6. Component Test sequence will function as follows:
38
a. Inducer motor starts on high-speed and continues to run until Step (d.) of component test sequence.
38
b. Hot surface igniter is energized for 15 sec, then de-energized.
38
c. Blower operates for 10 sec, then turns off.
38
d. Inducer motor goes to low-speed for 10 seconds, then turns off.
38
e. After component test is completed, one or more status codes heartbeat, 2+5 will flash. See component test section of service label for explanation of status codes.
39
f. Turn setup switch SW1-6 OFF.
39
7. RELEASE BLOWER ACCESS DOOR SWITCH, reattach wire to “R” terminal on furnace control board, replace blower access door, and replace outer access door.
39
CARE AND MAINTENANCE
39
1. Spray or aerosol cans, rags, brooms, dust mops, vacuum cleaners, or other cleaning tools.
39
2. Soap powders, bleaches, waxes or other cleaning compounds, plastic or plastic containers, gasoline, kerosene, cigarette lighter fluid, dry cleaning fluids, or other volatile fluids.
39
3. Paint thinners and other painting compounds, paper bags, or other paper products. Exposure to these materials could lead to corrosion of the heat exchangers.
39
1. Check and clean air filter each month or more frequently if required. Replace if torn.
39
2. Check blower motor and wheel for cleanliness each heating and cooling season. Clean as necessary.
39
3. Check electrical connections for tightness and controls for proper operation each heating season. Service as necessary.
39
4. Inspect burner compartment before each heating season for rust, corrosion, soot or excessive dust. If necessary, have furnace and burner serviced by a qualified service agency.
39
5. Inspect the vent pipe/vent system before each heating season for rust, corrosion, water leakage, sagging pipes or broken fittings. Have vent pipes/vent system serviced by a qualified service agency.
39
6. Inspect any accessories attached to the furnace such as a humidifier or electronic air cleaner. Perform any service or maintenance to the accessories as recommended in the accessory instructions.
39
Cleaning and/or Replacing Air Filter
39
Media Cabinet Filter Procedures:
39
1. Turn off electrical supply to furnace before removing filter access door.
39
2. Remove filter cabinet door.
39
3. Slide filter out of cabinet.
39
4. If equipped with permanent, washable 3/4-in. (19 mm) filter, clean filter by spraying cold tap water through filter in opposite direction of airflow. Rinse filter and let dry. Oiling or coating of the filter is not recommended. See Table 17 for si...
39
5. If equipped with factory-specified disposable media filter, replace only with media filter having the same part number and size. For expandable replacement media, refer to the instructions included with the replacement media.
39
6. Slide filter into cabinet.
39
7. Replace filter cabinet door.
39
8. Turn on electrical supply to furnace.
39
Table 17 – Filter Size Information - In. (mm)
39
Blower Motor and Wheel
40
1. Turn off electrical supply to furnace.
40
2. Remove outer door.
40
3. For downflow or horizontal furnaces having vent pipes within the furnace that pass in front of the blower access door:
40
a. Disconnect vent connector from furnace vent elbow.
40
b. Disconnect and remove short piece of vent pipe from within furnace.
40
4. Remove 2 screws from blower access door and remove blower access door.
40
5. All factory wires can be left connected, but field thermostat connections may need to be disconnected depending on their length and routing.
40
6. Remove 2 screws holding blower assembly to blower deck and slide blower assembly out of furnace.
40
7. Clean blower wheel and motor using a vacuum with soft brush attachment. Blower wheel blades may be cleaned with a small paint or flux brush. Do not remove or disturb balance weights (clips) on blower wheel blades.
40
8. Vacuum any loose dust from blower housing, wheel and motor.
40
9. If a greasy residue is present on blower wheel, remove wheel from the blower housing and wash it with an appropriate degreaser.
40
a. Disconnect ground wire attached to blower housing.
40
b. Remove screws securing cutoff plate and remove cutoff plate from housing.
40
c. Loosen set screw holding blower wheel on motor shaft (160+/-20 in.-lb. when assembling).
40
d. Remove bolts holding motor to blower housing and slide motor out of wheel (40+/-10 in.-lb. when reassembling).
40
e. Remove blower wheel from housing.
40
f. Clean wheel and housing.
40
10. Reassemble motor and blower by reversing steps 9a, through 9e. Be sure to reattach ground wire to the blower housing.
40
11. Verify that blower wheel is centered in blower housing and set screw contacts the flat portion of the motor shaft. Loosen set screw on blower wheel and reposition if necessary.
40
12. Spin the blower wheel by hand to verify that the wheel does not rub on the housing.
40
13. Reinstall blower assembly in furnace.
40
14. Reinstall 2 screws securing blower assembly to blower deck.
40
15. Reconnect blower leads to furnace control. Refer to furnace wiring diagram, and connect thermostat leads if previously disconnected.
40
16. To check blower for proper rotation:
40
a. Turn on electrical supply.
40
b. Manually close blower access door switch.
40
c. Perform component self-test as shown at the bottom of the SERVICE label, located on the front of blower access door.
40
d. Verify blower is rotating in the correct direction
40
17. If furnace is operating properly, RELEASE BLOWER ACCESS DOOR SWITCH. Remove any jumpers or reconnect any disconnected thermostat leads. Replace blower access door.
40
18. Downflow or horizontal furnaces with vent pipe through furnace only:
40
a. Install and connect short piece of vent pipe inside furnace to existing vent.
40
b. Connect vent connector to vent elbow.
40
19. Reinstall outer door.
40
20. Turn on gas supply and cycle furnace through one complete heating and cooling cycle. Verify the furnace temperature rise as shown in Adjustments Section. Adjust temperature rise as shown in Adjustments Section. If outdoor temperature is below 70...
40
Cleaning Heat Exchanger
40
1. Turn OFF gas and electrical power to furnace.
40
2. Remove outer access door.
40
3. Disconnect vent connector from furnace vent elbow.
40
4. For downflow or horizontal furnace having an internal vent pipe, remove internal vent pipe within the casing.
40
5. Disconnect wires to the following components. Mark wires to aid in reconnection (be careful when disconnecting wires from switches because damage may occur):
40
a. Draft safeguard switch.
40
b. Inducer motor.
40
c. Pressure switches.
41
d. Limit overtemperature switch.
41
e. Gas valve.
41
f. Hot surface igniter.
41
g. Flame-sensing electrode.
41
h. Flame rollout switches.
41
6. Remove screws that fasten the collector box assembly to the cell panel. Be careful not to damage the collector box. Inducer assembly and elbow need not be removed from collector box.
41
7. Disconnect gas line from gas manifold.
41
8. Remove the four screws that attach the burner assembly to the cell panel. The gas valve and individual burners need not be removed from support assembly. Remove NOx baffles, if installed.
41
Fig. 50 – Igniter Position - Top View
41
Fig. 51 – Igniter Position - Side View
41
9. Using a field-provided 25-caliber rifle cleaning brush; a 36-in. (914 mm) long, 1/4-in. (6 mm) diameter steel spring cable; and a variable speed drill, do the following:
41
a. Remove metal screw fitting from wire brush to allow insertion into cable.
41
b. Insert the twisted wire end of brush into end of spring cable, and crimp tight with crimping tool or crimp by striking with ball-peen hammer. TIGHTNESS IS VERY IMPORTANT. After crimping:
41
(1.) Attach variable-speed, reversible drill to the end of spring cable (end opposite brush).
41
(2.) Insert brush end of cable into the outlet opening of cell and slowly rotate with drill, see Fig. 52. DO NOT force cable. Gradually insert cable into upper pass of cell.
41
A91252
41
Fig. 52 – Cleaning Heat Exchanger Cell
41
(3.) Work cable in and out of cell 3 or 4 times to obtain sufficient cleaning. DO NOT pull cable with great force. Reverse drill and gradually work cable out.
41
(4.) Insert brush end of cable in burner inlet opening of cell, and proceed to clean 2 lower passes of cell in same manner as upper pass.
41
(5.) Repeat foregoing procedures until each cell in furnace has been cleaned.
41
(6.) Using vacuum cleaner, remove residue from each cell.
41
(7.) Using vacuum cleaner with soft brush attachment, clean burner assembly.
41
(8.) Clean flame sensor with fine steel wool.
41
(9.) Install NOx baffles (if removed).
41
(10.) Reinstall burner assembly. Center burners in cell openings.
41
10. Remove old sealant from cell panel and collector box flange.
41
11. Spray releasing agent on the heat exchanger cell panel where collector box assembly contacts cell panel.
41
12. Apply new sealant to flange of collector box and attach to cell panel using existing screws, making sure all screws are secure.
41
13. Reconnect wires to the following components (Use connection diagram on wiring label, if wires were not marked for reconnection locations.):
41
a. Draft safeguard switch.
41
b. Inducer motor.
41
c. Pressure switches.
41
d. Limit overtemperature switch.
41
e. Gas valve.
41
f. Hot surface igniter.
41
g. Flame-sensing electrode.
41
h. Flame rollout switches.
41
14. Reinstall internal vent pipe, if applicable.
41
15. Reinstall vent connector on furnace vent elbow. Securely fasten vent connector to vent elbow with 2 field-supplied, corrosion-resistant, sheet metal screws located 180° apart.
41
16. Replace blower access door only if it was removed.
41
17. Set thermostat above room temperature and check furnace for proper operation.
41
18. Verify blower airflow and speed changes between heating and cooling.
41
19. Check for gas leaks.
42
SEQUENCE OF OPERATION
42
1. Two-Stage Heating (Adaptive Mode) with Single-Stage Thermostat.
42
a. Inducer Prepurge Period
42
(1.) If the furnace control CPU selects low-heat operation the inducer motor IDM comes up to speed, the low-heat pressure switch LPS closes, and the furnace control CPU begins a 15-second prepurge period. If the low-heat pressure switch LPS fails to ...
42
(2.) If the furnace control CPU selects high-heat operation, the inducer motor IDM remains running at high-speed, and the high-heat pressure switch relay HPSR is de-energized to close the NC contact. When sufficient pressure is available the high-hea...
42
b. Igniter Warm-Up -At the end of the prepurge period, the Hot-Surface Igniter HSI is energized for a 17-second igniter warm-up period.
42
c. Trial-For-Ignition Sequence -When the igniter warm-up period is completed the main gas valve relay contact GVR closes to energize the gas valve solenoid GV-M. The gas valve solenoid GV-M permits gas flow to the burners where it is ignited by the H...
42
d. Flame-Proving - When the burner flame is proved at the flame-proving sensor electrode FSE, the inducer motor IDM switches to low-speed unless the furnace is operating in high-heat, and the furnace control CPU begins the blower-ON delay period and ...
42
e. Blower-On delay - If the burner flame is proven the blower-ON delays for low-heat and high-heat are as follows:
42
f. Switching from Low- to High-Heat - If the furnace control CPU switches from low-heat to high-heat, the furnace control CPU will switch the inducer motor IDM speed from low to high. The high-heat pressure switch relay HPSR is de-energized to close ...
42
g. Switching from High- to Low-Heat -The furnace control CPU will not switch from high-heat to low-heat while the thermostat R-to-W circuit is closed when using a single-stage thermostat.
42
h. Blower-Off Delay -When the thermostat is satisfied, the R to W circuit is opened, de-energizing the gas valve GV-M, stopping gas flow to the burners, and de-energizing the humidifier terminal HUM. The inducer motor IDM will remain energized for a ...
43
2. Two-Stage Thermostat and Two-Stage Heating See Fig. 28 - Fig. 31 for thermostat connections.
43
a. Switching from Low- to High-Heat - If the thermostat R-to-W1 circuit is closed and the R-to-W2 circuit closes, the furnace control CPU will switch the inducer motor IDM speed from low to high. The high-heat pressure switch relay HPSR is de-energiz...
43
b. Switching from High- to Low-Heat -If the thermostat R-to- W2 circuit opens, and the R-to-W1 circuit remains closed, the furnace control CPU will switch the inducer motor IDM speed from high to low. The high-heat pressure switch relay HPSR is energ...
43
3. Cooling mode The thermostat “calls for cooling.”
43
a. Single-Speed Cooling- See Fig. 28 for thermostat connections The thermostat closes the R-to-G-and-Y circuits. The R-to- Y circuit starts the outdoor unit, and the R-to-G-and-Y/Y2 circuits start the furnace blower motor BLWM on cooling airflow. Coo...
43
b. Two-Stage Thermostat and Two-Speed Cooling. See Fig. 29 for thermostat connections. The thermostat closes the R-to-G-and-Y1 circuits for low-cooling or closes the R-to-G-and-Y1-and-Y2 circuits for high-cooling. The R-to-Y1 circuit starts the outdo...
43
4. Dehumidify Mode See Fig. 28 - Fig. 31 for thermostat connections. The dehumidification output, DHUM on the Thermostat should be connected to the furnace control thermostat terminal DHUM. When there is a dehumidify demand, the DHUM input is activat...
43
a. Low cooling-When the R-to-G-and-Y1 circuit is closed and there is a demand for dehumidification, the furnace blower motor BLWM will drop the blower airflow to 86 percent of low-cooling airflow which is the true on-board CF (continuous fan) selecti...
43
b. High cooling-When the R-to-G-and Y/Y2 circuit is closed and there is a demand for dehumidification, the furnace blower motor BLWM will drop the blower airflow to 86 percent of high-cooling airflow. High-cooling airflow is based on the A/C (air con...
43
c. Cooling off-delay-When the “call for cooling” is satisfied and there is a demand for dehumidification, the cooling blower-off delay is decreased from 90 seconds to 5 seconds.
43
5. Super-Dehumidify Mode Super-Dehumidify mode can only be entered if the furnace control is in the Dehumidify mode and there is a demand for dehumidification. The cooling operation described in item 3. above also applies to operation with a thermost...
43
a. When the R-to-Y1 circuit is closed, R-to-G circuit is open, and there is a demand for dehumidification, the furnace blower motor BLWM will drop the blower airflow to 65 percent of low-cooling airflow for a maximum of 10 minutes each cooling cycle ...
43
b. When the R-to-Y/Y2 circuit is closed, R-to-G circuit is open, and there is a demand for dehumidification, the furnace blower motor BLWM will drop the blower airflow to 65 percent of high-cooling airflow for a maximum of 10 minutes each cooling cyc...
43
c. When the “call for cooling” is satisfied and there is a demand for dehumidification, the cooling blower-off delay is decreased from 90 seconds to 5 seconds.
43
6. Continuous Blower Mode When the R-to-G circuit is closed by the thermostat, the blower motor BLWM will operate at continuous blower airflow. Continuous blower airflow selection is initially based on the CF (continuous fan) selection, see Fig. 14. ...
43
7. Heat pump See Fig. 30 - Fig. 31 for thermostat connections. When installed with a heat pump, the furnace control automatically changes the timing sequence to avoid long blower off times during demand defrost cycles. Whenever W/W1 is energized alon...
44
8. Component test The furnace features a component test system to help diagnose a system problem in the case of a component failure. To initiate the component test procedure, ensure that there are no thermostat inputs to the control and all time dela...
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a. The furnace control CPU turns the inducer motor ON at high-heat speed and keeps it ON through step c.
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b. After waiting 10 seconds the furnace control CPU turns the hot surface igniter ON for 15 seconds, then OFF.
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c. The furnace control CPU then turns the blower motor BLWM on at mid-range airflow for 15 seconds, then OFF.
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d. After shutting the blower motor OFF the furnace control CPU switches the inducer to low-heat speed for 10 seconds, then OFF.
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Wiring Diagram
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Troubleshooting
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WIRING DIAGRAM
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A210194
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Fig. 53 – Wiring Diagram
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TROUBLESHOOTING GUIDE
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A190160
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A190159
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Fig. 54 – Troubleshooting Guide
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PARTS REPLACEMENT INFORMATION GUIDE
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CASING GROUP
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ELECTRICAL GROUP
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BLOWER GROUP
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GAS CONTROL GROUP
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HEAT EXCHANGER GROUP
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INDUCER GROUP
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EXAMPLE OF MODEL NUMBER
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Comfortmaker F80CTL Specifications
General
Brand
Comfortmaker
Model
F80CTL
Category
Furnace
Language
English
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