Haier GE NF97UM Service Manual
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Haier GE NF97UM Service Manual

Haier GE NF97UM Service Manual

97% upflow/horizontal modulating variable speed gas furnace
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Service
NF97UM
97% Upflow/Horizontal Modulating
Manual
Variable Speed Gas Furnace
READ CAREFULLY.
.
KEEP THESE INSTRUCTIONS
31-5000723 Rev. 0 11-22 GEA

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  • Page 1 Service NF97UM 97% Upflow/Horizontal Modulating Manual Variable Speed Gas Furnace READ CAREFULLY. KEEP THESE INSTRUCTIONS 31-5000723 Rev. 0 11-22 GEA...

  • Page 2: Table Of Contents

    SERVICE MANUAL NF97UM Gas Furnace 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. NF97UM series units are high-efficiency upflow, horizontal Table of Contents right and left) gas furnaces equipped with variable capacity gas valve, variable speed combustion air inducer...

  • Page 3: Technical Specifications - Nf97Um

    Technical Specifications - NF97UM MODEL NUMBER GUIDE N F F 97 97 U U M M 5 5 C C XX BRAND MAJOR/MINOR REVISION N - GE CABINET WIDTH PRODUCT B - 17.5 F - FURNACE, GAS C - 21.0 D - 24.5 AFUE NOMINAL CFM...
  • Page 4 BLOWER PERFORMANCE: BOTTOM INLET Heating Cooling Motor Temp CFM @ 0" - 0.8" w.c. CFM @ 0" - 0.8" w.c. Blower Cooling Speed Model Size Rise Size Stages Adjustment 100% Medium Medium High (hp) F° Input Input Input High Default +15% 1128 +10%...
  • Page 5 BLOWER PERFORMANCE: SIDE INLET Heating Cooling Motor Temp CFM @ 0" - 0.8" w.c. CFM @ 0" - 0.8" w.c. Blower Cooling Speed Model Size Rise Size Stages Adjustment 100% Medium Medium High (hp) F° Input Input Input High Default +15% 1093 +10%...
  • Page 6 BLOWER PERFORMANCE: SIDE INLET WITH RETURN AIR BASE Heating Cooling Motor Temp CFM @ 0" - 0.8" w.c. CFM @ 0" - 0.8" w.c. Blower Cooling Speed Model Size Rise Size Stages Adjustment 100% Medium Medium High (hp) F° Input Input Input High...
  • Page 7 ACCESSORY LIST Catalog Number Description Natural to LP Kits 68W77 Modulating 97% (including gas valve) Return Air Base 68W62 17.5" B Width 68W63 21.0" C Width 68W64 24.5” D Width Flush Mount Termination (90% Furnaces only) US Only 51W11 2” & 3.0” Vent Concentric Vent Kit (90% Furnaces only) US Only 71M80 1-1/2”...

  • Page 8: Parts Arrangement

    Parts Arrangement BURNER BOX ASSEMBLY PRESSURE SWITCHES HEAT EXCHANGER VARIABLE CAPACITY PRIMARY LIMIT GAS VALVE VARIABLE SPEED COMBUSTION AIR INDUCER BAG ASSEMBLIES (shipping location) COLD END HEADER ACCESS PANEL VARIABLE SPEED BLOWER MOTOR SHIPPING BLOCK (-135 UNITS ONLY) CONTROL BOX (includes variable capacity integrated control transformer, circuit breaker and door switch) Figure 1.

  • Page 9: Unit Components

    Circuit Breaker (CB8) Unit Components A 24V circuit breaker is also located in the control box. The switch provides overcurrent protection to the transformer NF97UM unit components are shown in Figure 1. The gas (T1). The breaker is rated 3A at 32V. If the current exceeds valve, combustion air inducer and burners can be accessed this limit the breaker will trip and all unit operation will by removing the access panel.
  • Page 10 Thermostat Selection Modes Pin # Function See Table 3 for DIP switch settings Not Used High Fire Pressure Switch The control can be made to operate in three modes: variable capacity, three-stage timed or two-stage. The variable Rollout Switch In capacity and two-stage modes are only operational with Ground a two-stage thermostat.
  • Page 11 NEUTRAL TERMINALS COMBUSTION AIR INDUCER CONNECTOR IGNITOR FLAME CONNECTOR SENSE DIAGNOSTIC LINE VOLTAGE PUSH BUTTON TERMINALS DIP SWITCHES INDOOR BLOWER CONNECTOR OUTDOOR AIR SENSOR TERMINALS 7-SEGMENT DIAGNOSTIC LED W915 Y1 TO Y2 DISCHARGE AIR SENSOR W951 R TO O TERMINALS W914 R TO DS FACTORY TEST W915...
  • Page 12 Figure 5. Integrated Control Configuration Guide Page 12 31-5000723 Rev. 0...
  • Page 13 Operation Thermostat Switch 1 Switch 2 Switch 3 Variable Capacity Heat Two-Stage (40% to 100%) 2nd Stage Delay OF = 7 minutes Three-Stage Heat Single-Stage ON = 12 minutes (40%, 70%, 100%) 3rd Stage Delay 10 minutes fixed Two-Stage Heat Two-Stage (W1 70%, W2 100%) Table 3.
  • Page 14 to operate as normal. This mode is used to check motor Ramping Option C operation. • Motor runs at 100% until demand is satisfied. • Once demand is met, motor runs at 100% for 45 seconds Adjustment Switch 10 Switch 11 then ramps down to stop.
  • Page 15 +15% Airflow Determination Identify blower speed adjustment points at low and high fire Airflow will lie on straight line between these two points and will fall within +7.5% the shaded area as shown EXAMPLE -7.5% at low fire +7.5% at high fire Nominal High Fire -7.5%...
  • Page 16 • Initiate furnace ignition sequence and move to and hold During Field Test mode operation, all safety switches are mid-fire rate by applying a jumper to R and W2. still in the circuit (they are not by-passed) and indoor blower performance and timings will match DIP switch selections.

  • Page 17: Configuring Unit Size Codes

    Configuring Unit Size Codes Power-Up - Number displayed by integrated control represents unit size code (furnace model and capacity). If three horizontal bars are displayed followed by continuous E203, furnace control does not recognize unit size code. Configure per the following: Turn room thermostat to OFF.

  • Page 18: Led Diagnostic Codes

    LED Diagnostic Codes Code Diagnostic Codes / Status of Equipment Action Required to Clear and Recover Idle mode (Decimal blinks at 1 Hertz - 0.5 seconds ON, 0.5 seconds OFF). Cubic feet per minute (cfm) setting for indoor blower (1 second ON, 0.5 seconds OFF) / cfm setting for current mode displayed.
  • Page 19 Code Diagnostic Codes / Status of Equipment Action Required to Clear and Recover E202 Indoor blower motor mismatch - indoor motor Incorrect appliance capacity code selected. Check for horsepower does not match unit capacity proper configuring under Unit Size Code for Furnace/ Air Handler on configuration guide or in installation instructions.
  • Page 20 Code Diagnostic Codes / Status of Equipment Action Required to Clear and Recover E240 Low flame current - Run mode- Refer to Check micro-amperes of flame sensor using control troubleshooting diagnostics or field installed mode. Clean or replace sensor. Measure voltage of neutral to ground to ensure good unit ground.
  • Page 21 Code Diagnostic Codes / Status of Equipment Action Required to Clear and Recover E292 Indoor blower motor unable to start due to Indoor blower motor unable to start (seized bearing, obstructed wheel seized bearings. stuck wheel, etc.) Replace motor or wheel if assembly does not operate or meet performance standards.
  • Page 22 Operating Sequence System Demand System Response Thermostat Relative Humidity Blower Demand System Step Compressor Comments Condition (COOL) Status Stage NO CALL FOR DEHUMIDIFICATION Compressor and indoor Normal Operation Acceptable 24 VAC High 100% blower follow thermostat demand BASIC MODE (only active on a Y1 thermostat demand) Normal Operation Acceptable 24 VAC...
  • Page 23 Operating Sequence System Demand System Response Thermostat Demand Relative Humidity Blower System Step Compressor Comments Condition (COOL) Status Stage Stage NO CALL FOR DEHUMIDIFICATION Normal Operation Acceptable Compressor and indoor - Y1 blower follow thermostat Normal Operation demand Acceptable High 100% - Y2 ROOM THERMOSTAT CALLS FOR FIRST STAGE COOLING...
  • Page 24 Indoor Blower Motor A solid-state controller is permanently attached to the motor. The controller is primarily an A.C. to D.C. converter. Converted D.C. power is used to drive the motor. The controller contains a microprocessor which monitors varying conditions inside the motor (such as motor workload). STATOR (WINDINGS) BEARING...
  • Page 25 Remove Blower from Unit Motor Start-Up 1. Remove unit access panels, control box, bolts and When B3 begins start-up, the motor gently vibrates back wiring jackplugs. and forth for a moment. This is normal. During this time the electronic controller is determining the exact position of the 2.
  • Page 26 P48 5 Pin P48 5 Pin P49 4 Pin SHAFT SHAFT P49 4 Pin MOTOR with INTEGRATED MOTOR with INTEGRATED CONTROLLER CONTROLLER J48 5 Pin J49 4 Pin P48 5 Pin P49 4 Pin J49 4 Pin Control Connector J48 5 Pin Line Voltage Connector J48 Connector 120v Figure 9.
  • Page 27 Troubleshooting Motor Windings TEST B Ensure that motor windings are not damaged by performing Use an ohmmeter to measure the motor phase-to-phase the following tests: resistance by checking these combinations of the the 3-pin motor plug. For the purpose of this test, start at either end of NOTE: If your ohm meter is not an auto-ranging type, set the connector as lead 1.
  • Page 28 Flame Rollout Switches that is precisely matched to the burner input. Burners can be removed as a one piece assembly for service. If burner Flame rollout switch S47 is a high temperature limit located assembly has been removed, it is critical to align center of inside the burner box.
  • Page 29 Primary Limit Control (S10) Figure 15 shows the primary limit (S10) used on A97USMV DANGER units located in the heating vestibule panel. When excess Danger of explosion. heat is sensed in the heat exchanger, the limit will open. Once the limit opens, the furnace control energizes the There are circumstances in which odorant supply air blower and de-energizes the gas valve.
  • Page 30 Finally, the switch interrupts the combustion process if the • Venting conditions change (affecting high and low condensate drainage system becomes blocked to the point pressure switch operation) the condensate level builds up in the cold end header box/ • Ramp down low fire switch check failed (calibration will secondary coil or vent system.
  • Page 31 5. If low pressure switch opens turn off inducer. No further The CAI is installed on the cold end header box. The cold action. end header box is a single piece made of hard plastic. The box has an internal channel where the combustion 6.
  • Page 32 Intake Air Pipe Exhaust Pipe Cold End Header Box Pipe Clamp Exhaust Connector Blower Deck Seal with Alignment Tabs Exhaust Coupling Drain Cap Exhaust Elbow Tubing Combustion Air Inducer (CAI) Clamp Intake Air Coupling CAI Embossment Figure 19. Combustion Air Inducer / Cold End Header Box / Vent Pipe Assembly Page 32 31-5000723 Rev.

  • Page 33: Placement And Installation

    Canadian Applications Only - Pipe, fittings, primer and Placement and Installation solvent cement used to vent (exhaust) this appliance must be certified to ULC S636 and supplied by a single manufacturer All pipe, fittings, primer and solvent cement must conform as part of an approved vent (exhaust) system.

  • Page 34: Joint Cementing Procedure

    STANDARD CONCENTRIC Outdoor Outdoor Exhaust 1-1/2” 2” 3” Exhaust Flush VENT Accelerator Concentric Concentric Concentric PIPE Accelerator Mount Kit (Dia. X Length) Unit DIA. (Dia. X Length) (in.) 71M80 69M29 60L46 1-1/2” X 12” 2” X 12” 51W11 * or 44W93+ +44W92++ +44W92++ 1-1/2...

  • Page 35: Venting Practices

    Exhaust Piping (Figure 21 and Figure 22) Venting Practices Route piping to outside of structure. Continue with installation following instructions given in piping termination section. SCHEDULE 40 PVC - 5' Intake Piping (Figure 21 and Figure 22) all other pipe* - 3' The NF97UM furnace may be installed only in direct vent applications.
  • Page 36 EXHAUST INTAKE 2” INTAKE EXHAUST 2” 2” 2” 2” 2” *2” *2” 070 Only 1-1/2” TRANSITION 2” 6” MINIMUM DO NOT transition from smaller to larger pipe in horizontal runs of exhaust pipe. * When transitioning up in pipe size, use the shortest length of 2” PVC pipe possible.

  • Page 37: Vent Piping Guidelines

    Vent Piping Guidelines Exhaust Pipe 12” Min. 12” Max. NOTE: GE Appliances has approved the use of DuraVent ® Horizontal and Centrotherm manufactured vent pipe and terminations Gas Furnace as an option to PVC. When using the PolyPro by DuraVent ®...
  • Page 38 Use the following steps to correctly size vent pipe diameter. 070, 090, Furnace capacity? 110 or 135 btuh Standard or Which termination? Concentric? See Table 20 Which needs most Intake or elbows? Exhaust? How many? 1-1/2”, 2”, Desired pipe size? 2-1/2”...
  • Page 39 Maximum Allowable Intake or Exhaust Vent Length (feet) Standard Termination at Elevation 0 - 4,500 ft 1-1/2” Pipe 2” Pipe 2-1/2” Pipe 3” Pipe Number of 90° Elbows Model Model Model Model Used Standard Termination at Elevation 4,501 - 10,000 ft 1-1/2”...
  • Page 40 Maximum Allowable Intake or Exhaust Vent Length (feet) Concentric Termination at Elevation 0 - 4,500 ft 1-1/2” Pipe 2” Pipe 2-1/2” Pipe 3” Pipe Number of 90° Elbows Model Model Model Model Used Concentric Termination Elevation 4,501 - 10,000 ft 1-1/2”...
  • Page 41 General Guidelines for Vent Terminations In Direct Vent applications, combustion air is taken from IMPORTANT outdoors and the flue gases are discharged to the outdoors. The NF97UM is then classified as a direct vent, Category IV For Canadian Installations Only: gas furnace.
  • Page 42 Maximum Allowable Vent Pipe Length without Insulation in Unconditioned Space for Winter Design Temperatures Modulating High Efficiency Furnace Winter Design Temperatures ºF Vent Pipe (ºC) Diameter 1-1/2 in. 32 to 21 2 in. (0 to -6) 2-1/2 in. 3 in. 1-1/2 in.
  • Page 43 VENT TERMINATION CLEARANCES FOR DIRECT VENT INSTALLATIONS IN THE USA AND CANADA INSIDE CORNER DETAIL Fixed Operable Fixed Closed Closed Operable AREA WHERE TERMINAL AIR SUPPLY INLET VENT TERMINAL IS NOT PERMITTED US Installations Canadian Installations Clearance above grade, veranda, 12 inches (305mm) or 12 in.
  • Page 44 Details of Intake and Exhaust Piping Terminations 2. Intake and exhaust pipes should be placed as close together as possible at termination end (refer to for Direct Vent Installations illustrations). Maximum separation is 3” (76MM) on roof NOTE: In Direct Vent installations, combustion air is taken terminations and 6”...
  • Page 45 between the end of the exhaust pipe and the end of STRAIGHT-CUT OR the intake pipe without a termination elbow is 8” and a ANGLE-CUT IN DIRECTION OF ROOF SLOPE * minimum distance of 6” with a termination elbow. See Figure 35.
  • Page 46 FIELD FABRICATED WALL TERMINATION NOTE − FIELD−PROVIDED REDUCER MAY BE 2” (51mm) 3” (76mm) REQUIRED TO ADAPT LARGER VENT PIPE SIZE Vent Pipe Vent Pipe TO TERMINATION A− Minimum clearance above grade or average 12” (305 mm) 12” (305 mm) snow accumulation B−...

  • Page 47: For The Province Of Ontario, Horizontal Sidewall Vent Applications Only

    For the Province of Ontario, Horizontal Sidewall Vent Applications Only For exterior horizontal venting applications, the 2” X 1.5” reducer for 2” venting at the point where the exhaust pipe exits the structure is not required in direct or nondirect vent applications in the Province of Ontario. In these applications, the vent should be oriented such that the exhaust plume is unobjectionable.

  • Page 48: Condensate Piping

    1. Determine which side condensate piping will exit the Condensate Piping unit, location of trap, field-provided fittings and length of PVC pipe required to reach available drain. This unit is designed for either right- or left-side exit of 2. For furnaces with a 1/2” drain connection use a 3/8 allen condensate piping in upflow applications.
  • Page 49 line should be routed within the conditioned space to avoid freezing of condensate and blockage of drain line. If this is not possible, a heat cable kit may be used on the condensate trap and line. Elbow Evaporator drain line required Barbed Fitting (Trap at coil is optional) Tubing...
  • Page 50 Evaporator drain From Evaporator Coil line required Field Provided Vent 1” min. 2” max. above (Trap at coil is optional) condensate drain. Field-Provided Vent (1” min. to 2” Max.above condensate drain connection) Furnace Condensate Condensate Drain Condensate Drain Connection Optional Overflow Switch Figure 42.
  • Page 51 Optional Condensate Drain Connection Adapter 3/4 inch slip X 3/4 inch mpt (not furnished) 90° Street Elbow 3/4 inch PVC (not furnished) Adapter 3/4 inch slip X 3/4 inch mpt (not furnished) Condensate Drain Connection In Unit 1 (25 mm) Min. Vent 2 (50 mm) Max.
  • Page 52 Optional Condensate Drain Connection Adapter 1/2 inch slip X 1/2 inch mpt (Not Furnished) 90° Street Elbow 1/2 inch PVC (Not Furnished) Adapter 1/2 inch slip X 1/2 inch mpt (Not Furnished) Condensate Drain Connection In Unit 1 (25 mm) Min. Vent 2 (50 mm) Max.

  • Page 53: Start-Up

    the thermostat calls for heat, the burners will automatically Start-Up light The ignitor does not get hot when there is no call for heat on units with an ignition system. Preliminary and Seasonal Checks Priming Condensate Trap 1. Inspect electrical wiring, both field and factory installed The condensate trap should be primed with water prior to for loose connections.

  • Page 54: Heating System Service Checks

    4. This furnace is equipped with an ignition device which unit. All access panels and covers must be in place and automatically lights the burners. Do not try to light the secured. burners by hand. 5. Remove the upper access panel. Heating System Service Checks 6.
  • Page 55 Operating Pressure Signal (Delta P) Measurement When checking piping connections for gas leaks, use preferred means. Kitchen detergents can cause harmful (Figure 49) corrosion on various metals used in gas piping. Use of a Operating pressure signal can be taken while the manifold specialty Gas Leak Detector is strongly recommended.
  • Page 56 Gas Valve Field Installed Figure 48. Manifold Pressure Measurement Negative Port Positive Port Red and Black Tubing or Red Tubing - Black Tubing + Gas Valve Field Installed Measuring Device Figure 49. Operating Signal (Delta P) Measurement Page 56 31-5000723 Rev. 0...
  • Page 57 Proper Combustion High Altitude NOTE: In Canada, certification for installations at elevations Furnace should operate minimum 15 minutes with correct manifold pressure and gas flow rate before checking over 4500 feet (1372 m) is the jurisdiction of local authorities. combustion. Take combustion sample beyond the flue outlet NF97UM units require no manifold pressure adjustments and compare to the tables below.

  • Page 58: Typical Operating Characteristics

    External Static Pressure Typical Operating Characteristics 1. Tap locations shown in Figure 50. Blower Operation and Adjustment 1. Blower operation is dependent on thermostat control system. 2. Generally, blower operation is set at thermostat subbase fan switch. With fan switch in ON position, blower operates continuously.

  • Page 59: Maintenance

    Filter Size Maintenance Furnace Cabinet Width Side Return Bottom Return 17-1/2” 16 x 25 x 1 (1) 16 x 25 x 1 (1) 21” 20 x 25 x 1 (1) WARNING 24-1/2” 16 x 25 x 1 (2) 24 x 25 x 1 (1) ELECTRICAL SHOCK, FIRE, OR EXPLOSION Table 30.
  • Page 60 Condensate Hose Screens (Figure 51) 10. Disconnect condensate drain tubing from flue collar. Remove screws that secures the flue collar into place. Check the condensate hose screens for blockage and clean Remove flue collar. It may be necessary to cut the exiting if necessary.
  • Page 61 Cleaning the Burner Assembly 30. Reinstall pressure switches and reconnect pressure switch wiring. 1. Turn off electrical and gas power supplies to furnace. Remove upper and lower furnace access panels. 31. Carefully connect combustion air pressure switch hosing from pressure switches to proper stubs on cold end 2.

  • Page 62: Wiring And Sequence Of Operation

    Wiring and Sequence of Operation 120VAC XFMR GRN/YEL CIRC BLACK WHITE DOOR GN/YLW INTERLOCK INTEGRATED CONTROL IGNITOR HUMIDIFIER CIRC FLAME WHT/PNK SENSE FLAME SENSOR 120V BLUE BLUE MV COM PINK PURPLE S102 HIGH HEAT PRESSURE SWITCH PINK PINK S128 LOW HEAT PRESSURE SWITCH BLUE BRN W/YEL...
  • Page 63 NEUTRAL TERMINALS COMBUSTION AIR INDUCER CONNECTOR IGNITOR CONNECTOR FLAME SENSE DIAGNOSTIC LINE VOLTAGE PUSH BUTTON TERMINALS DIP SWITCHES INDOOR BLOWER CONNECTOR OUTDOOR AIR SENSOR TERMINALS 7-SEGMENT DIAGNOSTIC LED W915 Y1 TO Y2 DISCHARGE AIR SENSOR W951 R TO O TERMINALS W914 R TO DS FACTORY TEST W915...
  • Page 64 Sequence of Operation 7. When the demand for first- and second-stage heat is satisfied, the gas valve is de-energized and the field- NOTE: The ignition control thermostat selection DIP switch selected indoor blower off delay begins. The combustion is factory-set in the “TWO-STAGE” position. air inducer begins a 20-second post-purge period.
  • Page 65 Applications Using a Two-Stage Thermostat C - Heating Sequence -- Control Thermostat Selection DIP switch in “Two-Stage” Position (Factory Setting) 1. On a call for heat, thermostat first-stage contacts close sending a signal to the integrated control. The integrated control runs a self-diagnostic program and checks high temperature limit switches for normally closed contacts and pressure switches for normally open contacts.

  • Page 66: Field Wiring Applications With Conventional Thermostat

    Field Wiring Applications with Conventional Thermostat DIP Switch Settings and On-Board Links W915 W914 W951 Thermostat Wiring Connections DIP Switch 1 (Y1 to Y2) (DS to R) (O to R) Two-Stage Cooling Dehumidification Heat Pumps CONTROL OUTDOOR T'STAT TERM. STRIP UNIT 1 Heat / 1 Cool NOTE:...
  • Page 67 DIP Switch Settings and On-Board Links W915 W914 W951 Thermostat Wiring Connections DIP Switch 1 (Y1 to Y2) (DS to R) (O to R) Two-Stage Cooling Dehumidification Heat Pumps CONTROL OUTDOOR T'STAT TERM. STRIP UNIT 2 Heat / 2 Cool Intact Intact CONTROL...
  • Page 68 DIP Switch Settings and On-Board Links W915 W914 W951 Thermostat Wiring Connections DIP Switch 1 (Y1 to Y2) (DS to R) (O to R) Two-Stage Cooling Dehumidification Heat Pumps CONTROL T'STAT TERM. STRIP HEAT PUMP 67M41** Dual Fuel Single- Stage Heat Pump thermostat w/dual Intact Intact...

  • Page 69: Sequence Of Operation And Troubleshooting Flow Chart

    Sequence of Operation and Troubleshooting Flow Chart Safety Check Verify There Is No Main Burner Flame Indoor blower OFF After Heat OFF Delay (Low Heat Speed) Combustion Air Limit Limit Indoor Blower De−Energize Error Code Inducer On Switch Closes Within 3 Gas Valve Flashes ON (100%)
  • Page 70 2 Stage Thermostat 1st Call for High Fire? 2nd Stage Recognition Delay (30 Seconds) Combustion Air Inducer ON (100% Rate Speed) High Pressure Switch Increase Combustion Error Code Wait 5 Closes Within Air Inducer Speed Flashes Minutes 10 Seconds? if Not at 100% Rate Speed Adjust Indoor Blower to...
  • Page 71 RUN MODE (2 STAGE THEREMOSTAT) RUN MODE (SINGLE STAGE THERMOSTAT) 1ST OR 2ND STAGE CALL FOR HEAT ALL ALL INPUTS MONITORED (LIMIT, PRESSURE, INPUTS MONITORED (LIMIT, PRESSURE, CALL FOR HEAT / COOL, FLAME LEVEL) CALL FOR HEAT / COOL, FLAME LEVEL) 2nd Stage Heat 2nd Stage Call for Heat...
  • Page 72 Safety Check Verify There Is No Main Burner Indoor Blower OFF After Flame Heat OFF Delay (Low Heat Speed) Indoor Blower Limit Limit De−Energize Combustion Air Error Code Switch Closes Within 3 Gas Valve Flashes Inducer ON (100% Speed) Closed? Minutes? (100%) Indoor Blower OFF...
  • Page 73 1st Stage Cooling Request Received Energize 1st Stage Cooling Contactor (Compressor & Fan) Indoor Blower On After 2−second delay Energize Indoor Blower (Per Ramping Profile) 1st Stage 2nd Stage Cooling Request Cooling Still Active? Request? Energize 2nd Stage Energize Indoor Blower Cooling Contactor (High Cooling mode) (Compressor &...
  • Page 74 Call for Continuous Blower Indoor Blower On (Speed Determined by Dip Switch settings) Request Maintain Indoor for Cooling Go to Call for Cooling Blower at set speed Received? Go to Call for Heat - 2 Stage Thermostat Request Maintain Indoor for Heat Blower at set speed Received?
  • Page 75 Notes Page 75 31-5000723 Rev. 0...
  • Page 76 All specifications and illustrations subject to change without notice and without incurring obligations. Printed in the U.S.A.

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