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Lennox G60UHV Service Manual

G60uhv series; g60uhvx series
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Service Literature
G60UHV(X) series units are mid−efficiency gas furnaces
used for upflow or horizontal applications only, manufac-
tured with Lennox Duralok Plus heat exchangers formed of
aluminized steel. G60UH(X) units are available in heating
capacities of 66,000 to 132,000 Btuh and cooling applica-
tions up to 5 tons. Refer to Engineering Handbook for prop-
er sizing.
Units are factory equipped for use with natural gas. Kits are
available for conversion to LPG operation. G60UH(X) model
units are equipped with the Two−Stage / Variable Speed Inte-
grated SureLight control. G60UH(X) unit meets the Califor-
nia Nitrogen Oxides (NO
) Standards and California Sea-
x
sonal Efficiency requirements. All units use a redundant gas
valve to assure safety shut−off as required by C.S.A.
All specifications in this manual are subject to change. Pro-
cedures outlined in this manual are presented as a recom-
mendation only and do not supersede or replace local or
state codes. In the absence of local or state codes, the
guidelines and procedures outlined in this manual (except
where noted) are recommendations only and do not consti-
tute code.

TABLE OF CONTENTS

Introduction

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . .
II Installation
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
III Start Up
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IV Heating System Service Checks
V Typical Operating Characteristics
VI Maintenance
. . . . . . . . . . . . . . . . . . . . . . . . . .
VII Wiring and Sequence of Operation
VIII Field Wiring and Jumper Settings
IX Troubleshooting
. . . . . . . . . . . . . . . . . . . . . . .
Corp. 0124−L11
Revised 1−2009
G60UHV(X) SERIES UNITS
Page 1
Page 2
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Page 7
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Page 32
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Page 35
Page 36
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Page 38
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Page 58
Page 1
G60UHV(X)
IMPORTANT
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person-
al injury or loss of life. Installation and service must
be performed by a qualified installer, service agency
or the gas supplier.
WARNING
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at discon-
nect switch(es). Unit may have multiple
power supplies.
WARNING
Sharp edges.
Be careful when servicing unit to avoid sharp edges
which may result in personal injury.
© 2003 Lennox Industries Inc.

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Summary of Contents for Lennox G60UHV

  • Page 1 G60UHV(X) series units are mid−efficiency gas furnaces used for upflow or horizontal applications only, manufac- tured with Lennox Duralok Plus heat exchangers formed of aluminized steel. G60UH(X) units are available in heating capacities of 66,000 to 132,000 Btuh and cooling applica- tions up to 5 tons.

  • Page 2: Specifications

    SPECIFICATIONS Model No. G60UHV−36A−070 G60UHV−36B−090 G60UHV−60C−090 Heating Low NOx Model No. G60UHV−36A−070X − − − G60UHV−60C−090X Performance Input − Btuh (kW) low fire 45,000 (13.2) 60,000 (17.6) 60,000 (17.6) Output − Btuh (kW) low fire 36,000 (10.5) 48,000 (14.1) 48,000 (14.1) Input −...

  • Page 3: Specifications

    SPECIFICATIONS Model No. G60UHV−60C−110 G60UHV−60D−135 Heating Low NOx Model No. G60UHV−60C−110X − − − Performance Input − Btuh (kW) low fire 75,000 (22.0) 90,000 (26.4) Output − Btuh (kW) low fire 60,000 (17.6) 72,000 (21.1) Input − Btuh (kW) high fire 110,000 (32.2)

  • Page 4: Blower Data

    Continuous Fan Only speed is approximately 38% of the same 2nd stage COOL speed position − minimum 500 cfm (235 L/s). Lennox Harmony IIt zone control applications − Minimum blower heating speed is approximately 75% of the 1st stage HEAT speed position.
  • Page 5 Continuous Fan Only speed is approximately 38% of the same 2nd stage COOL speed position. Lennox Harmony IIt zone control applications − Minimum blower heating speed is approximately 75% of the 1st stage HEAT speed position. Lennox Harmony IIt zone control applications − Minimum blower cooling speed is approximately 42% of the 2nd stage COOL speed position.
  • Page 6 Continuous Fan Only speed is approximately 38% of the same 2nd stage COOL speed position. Lennox Harmony IIt zone control applications − Minimum blower heating speed is approximately 75% of the 1st stage HEAT speed position. Lennox Harmony IIt zone control applications − Minimum blower cooling speed is approximately 42% of the 2nd stage COOL speed position.

  • Page 7: High Altitude

    Continuous Fan Only speed is approximately 38% of the same 2nd stage COOL speed position. Lennox Harmony IIt zone control applications − Minimum blower heating speed is approximately 75% of the 1st stage HEAT speed position. Lennox Harmony IIt zone control applications − Minimum blower cooling speed is approximately 45% of the 2nd stage COOL speed position.
  • Page 8 G60UHV(X) PARTS ARRANGEMENT Air Deflector Flue Box Gasket G60UH−60C−110 Gasket Units Only Flue Collector Heat Exchanger Flue Transition Combustion Air Orifice Combustion Air Prove Switch Assembly (two switches) Combustion Air Inducer Limit Shield Flame Sensor Flame Rollout Switches Air Intake...

  • Page 9: I Unit Components

    3. Circuit Breaker (CB8) A 24V circuit breaker is also located in the control box. G60UHV(X) unit components are shown in figure 1. The The switch provides overcurrent protection to the trans- gas valve, combustion air inducer and burners can be ac- former (T1).
  • Page 10 After the 15−second pre−purge period, the SureLight ignitor warms up for 20 seconds after which the gas valve opens for a 4−second trial for ignition. The ignitor energizes during the trial until flame is sensed. If ignition is not proved during TW0−STAGE, VARIABLE SPEED INTEGRATED the 4−second period, the control will try four more times with CONTROL BOARD...
  • Page 11 TABLE 1 TABLE 3 Two Stage Ignition / Blower Control Terminals SureLight Board 12Pin Terminal Designation LINE Line 120VAC Neutral PIN # Function XFMR Transformer 120VAC Neutral Gas Valve High Fire Electronic Air Cleaner 120VAC Neutral Second Stage Pressure Switch CIRC Indoor Blower 120VAC Neutral Not Used...

  • Page 12: Status Codes

    (2) second pauses. One blink equals roughly 100 CFM. DS7−ON indicaties the DS to R" jumper has not been cut. When the jumper is cut the system will be operating with LENNOX HARMONY IIt (See Harmony Installation Instructions) or YELLOW with the CCB1 Efficiency Plus control.

  • Page 13: Dip Switch Settings

    Page 14. See unit nameplate for manufacturing date. Switch 4 −− Not used in G60UHV application. TABLE 10 Switches 5 and 6 −− Cooling Mode Blower Speed −−...
  • Page 14 100% until demand is satisfied. 100% CFM D Once demand is met, motor ramps down to off. COOLING DEMAND * G60UHV units date coded prior to 2−2006 will delay 60 seconds 7−1/2 MIN 100% CFM 82%CFM...
  • Page 15 HEAT LED is lit when the indoor blower is operating at the HEATING speed. SignatureStatt. Refer to table 21 for operation sequence in applications including a G60UHV, CCB1 and single− speed outdoor unit. Table 22 gives the operation sequence in applications with a two−speed outdoor unit. Refer to table 23 for operation sequence in applications including a G60UHV, SignatureStat and single−speed outdoor unit.
  • Page 16 Board 100870 NOTE − Board 100870 provides a regulated 95 volts to Beginning with G60UHV−7, units are equipped with the to the ignitor. Lennox two−stage, variable speed integrated SureLight Two Stage Operation / Thermostat Selection Jumper control board.
  • Page 17 THERMOSTAT CONNECTIONS (TB1) DIAGNOSTIC LEDs HEATING INDOOR BLOWER DIP SWITCHES SWITCHES H= 24V HUMIDIFIER OUTPUT L= LENNOX SYSTEM OPERATION MONITOR 1= FUTURE USE ON−BOARD FUTURE LINKS DIP SWITCH FUNCTIONS HTG DIP SWITCH(ES) FUNCTION T’stat Heat Stages (single or two−stage) Second Stage ON Delay (single−stage t’stat)
  • Page 18 TWO−STAGE, VARIABLE SPEED INTEGRATED CONTROL BOARD FIGURE 6 Page 18...
  • Page 19 TABLE 15 FLASH CODE STATUS / ERROR DESCRIPTION (X + Y) FLASH CODE DESCRIPTIONS Pulse A 1/4 second flash followed by four seconds of off time. Heartbeat Constant 1/2 second bright and 1/2 second dim cycles. LED flashes X times at 2Hz, remains off for two seconds, flashes Y times at 2Hz, remains off for four X + Y seconds, then repeats.
  • Page 20 Dip Switch Settings operation during the cooling mode. The table below pro- vides the cooling mode blower speeds that will result from Heating Operation DIP Switch Settings different switch settings. Refer to blower tables at the front Switch 1 −− Thermostat Selection −− This unit may be used of this manual for corresponding cfm values.
  • Page 21 The green CFM LED indicates the blower air flow. Count (SignatureStatt) for operation sequence in applications the number of blinks between the two−second pauses to including G60UHV, a thermostat which features humidity determine the CFM. Each blink represents approximately control and a single−speed outdoor unit. Table 22 (CCB1) 100 CFM.
  • Page 22 TABLE 22 G60UHV, CCB1 and Two−Speed Outdoor Unit OPERATING MODE SYSTEM DEMAND SYSTEM RESPONSE System Thermostat *Relative Humidity ****Compressor Blower CFM Comments Condition Demand (EfficiencyPlus Lights) Speed (COOL) **42%/46%/49% Compressor demand and indoor No demand. Acceptable of HIGH COOL Normal operation...
  • Page 23 With Heat Pump − Cut W914 (R to DS) & W951 (R to O) on SureLight board Dave Lennox SignatureStat to use for this application − 51M26 1 heat / 1 cool or 51M28 − 2 heat / 2 cool for heat pumps *Dehumidification blower speed is 65% of COOL speed for 36A &...
  • Page 24 With Heat Pump − Cut W914 (R to DS) & W951 (R to O) on SureLight board Dave Lennox SignatureStat to use for this application − 51M27 2 heat / 2 cool or 51M28 − 2 heat / 2 cool for heat pumps *Normal operation first stage cooling blower speed is as follows for units built before 09−2002: 65% of COOL for 36A, 36B,...
  • Page 25 All G60UHV blower motors use single phase power. An external run capacitor is not used. The motor uses per- manently lubricated ball-type bearings.
  • Page 26 Power Choke (L13) ing to change speed taps. A choke coil is used on G60UHV 5 ton 1 hp units. The choke is located on the blower housing and is used to sup- DANGER press transient current spikes.
  • Page 27 MOTOR SPEED CONTROL WITH D.C. PULSE-WIDTH MODULATION Motor speed is determined by the size of the electrical pulse sent to the motor windings. The longer the pulse, the faster the motor. OUTPUT FROM CONTROLLER TO MOTOR WINDINGS WINDINGS TURNED OFF WINDINGS TURNED ON Ç...

  • Page 28: Flame Sensor

    7. Ignitor NOTE − The G60UHV(X) furnace contains electronic components that are polarity sensitive. Make sure that The SureLight ignitor is made of durable silicon nitride. Ig- the furnace is wired correctly and is properly grounded. nitor longevity is enhanced by controlling voltage to the ig- nitor.

  • Page 29: Combustion Air Inducer (B6)

    2.0" −135 2.25" 5/16" Horizontal Applications The G60UHV(X) furnace can be installed in horizontal ap- plications. The combustion air inducer may be rotated clockwise or counterclockwise by 90° to allow for vertical vent discharge FIGURE 14 in a horizontal application. Remove the four mounting...
  • Page 30 11. Primary Limit Control (S10) Optional Flue Outlet The primary limit (S10) on G60UHV(X) units is located in the (Horizontal Installation) heating vestibule panel. When excess heat is sensed in the Top View of Furnace heat exchanger, the limit will open. If the limit is open, the fur-...
  • Page 31 14. Combustion Air Inducer TABLE 26 0’ to 4500’ Prove Switch (S18) Set Point High Set Point Low G60UHV(X) series units are equipped with a dual combus- G60UHV(X) Unit Heat Heat tion air proving switch (first and second stage) located on −070 0.40"...

  • Page 32: Iii Start Up

    FIGURE 19 Shock and burn hazard. 8 − White Rodgers 36E Gas Valve − Switch gas valve lever G60UHV(X) units are equipped with a hot surface ignition system. Do not attempt to light manually. to ON. See figure 18. Honeywell VR8205 Gas Valve − Turn knob on gas 1 −...

  • Page 33: Iv Heating System Service Checks

    When pressure testing gas lines, the gas valve must be dis- justment. Manifold pressure for the G60UHV(X) can be mea- connected and isolated. Gas valves can be damaged if sured at any time the gas valve is open and is supplying gas subjected to more than 0.5 psig (14"...
  • Page 34 TABLE 29 IMPORTANT All G60UHV Units Natural Line Pressure WC" 4.5 − 10.5 11.0 − 13.0 For safety, shut unit off and remove manometer as Manifold Pressure High soon as an accurate reading has been obtained. 10.0 Heat WC" Take care to replace pressure tap plug.

  • Page 35: V Typical Operating Characteristics

    Current passes from the sensor through the flame to When the G60UHV(X) is running in the heating mode, ground to complete a safety circuit. the indoor blower will run on the heating speed desig- To Measure Flame Signal −...

  • Page 36: Vi Maintenance

    GASKET B−Filters All G60UHV(X) filters are installed external to the unit. Fil- ters should be inspected monthly. Clean or replace the fil- ters when necessary to ensure that the furnace operates properly. Replacement filters must be rated for high veloc- ity airflow.
  • Page 37 14− Replace collector box and combustion air inducer. NOx INSERTS Check gaskets for damage. Damaged gaskets must be (X models only) replaced to avoid heat exchanger leaks. Replace all screws to the collector box and combustion air inducer. Failure to replace all screws may cause leaks. 15−...

  • Page 38: Vii Wiring And Sequence Of Operation

    VII− Wiring and Sequence of Operation A−Wiring Diagram for G60UHV−1, −2 and −3 units Page 38...
  • Page 39 B−Sequence of Operation Single−Stage Thermostat, Two Stage Heat. Jumper E20 set at SINGLE" Sequence depends on type thermostat used. G60UHV 1− SureLight control energizes combustion air inducer B6 units are applicable for single stage or two stage ther- on low heat speed. Combustion air inducer runs until mostats.
  • Page 40 C−Flow Chart SureLight Boards 18M99 & 49M59 HEATING SEQUENCE OF OPERATION NORMAL AND ABNORMAL HEATING MODE GAS VALVE OFF. COMBUSTION AIR INDUCER POWER ON OFF. INDOOR BLOWER OFF. CHECK FOR BROKEN IGNITOR OR OPEN IGNITER CIRCUIT. DS 1 AND DS 2 ALTERNATING FAST FLASH. CONTROL SELF−CHECK OKAY? GAS VALVE OFF.
  • Page 41 HEATING SEQUENCE OF OPERATION CONTINUED THERMOSTAT CALLS FOR HEAT DS1 AND DS2 SIMULTANEOUS FAST FLASH (Refer to box A on previous page) FIRST−STAGE (LOW FIRE) PROVE GAS VALVE OFF. COMBUSTION AIR INDUCER SWITCH CLOSED WITHIN 2.5 MINUTES? OFF. INDOOR BLOWER OFF. UNIT WILL RETRY AFTER 5−MINUTE WAIT PERIOD.
  • Page 42 HEATING SEQUENCE OF OPERATION CONTINUED THERMOSTAT CALLS FOR HEAT. DS1 AND DS2 SIMULTANEOUS FAST FLASH. SEE BOX A. FLAME SIGNAL ABOVE (u0.23 microamps) LOW FLAME SIGNAL (Does not affect control operation) DS1 SLOW FLASH, DS2 FAST FLASH. SINGLE−STAGE THERMOSTAT MODE TWO STAGE THERMOSTAT MODE (E20 SET AT SINGLE") (E20 SET AT TWO")
  • Page 43 HEATING SEQUENCE OF OPERATION CONTINUED SEE BOX A NORMAL OPERATION DS1 AND DS2 SIMULTANEOUS SLOW FLASH. SEE BOX B THERMOSTAT CALLS FOR HEAT DS 1 AND DS 2 SIMULTANEOUS FAST FLASH GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. INDOOR BLOWER ON. IS PRIMARY AND SECONDARY LIMIT DS1 SLOW FLASH, DS2 ON, AND ROLLOUT SWITCH CLOSED?
  • Page 44 COOLING SEQUENCE OF OPERATION POWER ON IS POLARITY REVERSED? SIGNAL POLARITY REVERSED. DS1 FAST FLASH, DS2 SLOW FLASH. SIGNAL IMPROPER GROUND AT DS. IS THERE IS VOLTAGE LOW VOLTAGE SIGNAL AT DS HOLDS SIGNAL HOLDS PROPER GROUND? ABOVE 75 VOLTS? UNTIL VOLTAGE RISES ABOVE 75 VOLTS.
  • Page 45 D−Wiring Diagram for G60UHV−7 and later Page 45...
  • Page 46 E−Sequence of Operation Single−Stage Thermostat, Two Stage Heat. Dip Switch set at SINGLE" Sequence depends on type thermostat used. G60UHV 1− SureLight control energizes combustion air inducer B6 units are applicable for single stage or two stage ther- on low heat speed. Combustion air inducer runs until mostats.
  • Page 47 F−Flow Chart SureLight Board 100870 HEATING SEQUENCE OF OPERATION NORMAL AND ABNORMAL HEATING MODE POWER ON GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. INDOOR BLOWER OFF. (RESET CONTROL BY CONTROL SELF−CHECK OKAY? TURNING MAIN POWER OFF.) POLARITY REVERSED. POLARITY OKAY? STATUS ERROR CODE 5 + 4.
  • Page 48 HEATING SEQUENCE OF OPERATION CONTINUED THERMOSTAT CALLS FOR HEAT STATUS LED − HEARTBEAT (Refer to box A on previous page) FIRST−STAGE (LOW FIRE) PRESSURE GAS VALVE OFF. COMBUSTION AIR INDUCER SWITCH CLOSED WITHIN 2.5 MINUTES? OFF. INDOOR BLOWER OFF. UNIT WILL RETRY AFTER 5−MINUTE WAIT PERIOD.
  • Page 49 HEATING SEQUENCE OF OPERATION CONTINUED THERMOSTAT CALLS FOR HEAT. STATUS LED −− HEARTBEAT. SEE BOX A. FLAME SIGNAL ABOVE (u1.40 microamps) LOW FLAME SIGNAL (Does not affect control operation) STATUS ERROR CODE 1 + 2. SINGLE−STAGE THERMOSTAT MODE TWO STAGE THERMOSTAT MODE (DIP SWITCH SET AT SINGLE") (DIP SWITCH SET AT TWO") START SECOND−STAGE RECOGNITION...
  • Page 50 HEATING SEQUENCE OF OPERATION CONTINUED SEE BOX A NORMAL OPERATION. SEE BOX B THERMOSTAT CALLS FOR HEAT. RETURN TO FIRST−STAGE HEAT MODE. FIRST−STAGE CONTINUES UNTIL SECOND− STAGE PRESSURE SWITCH CAN BE PROVEN SECOND−STAGE (HIGH FIRE) HEAT or HEAT DEMAND IS SATISFIED. A FIVE (5) PRESSURE SWITCH CLOSED? MINUTE WAIT PERIOD IS INITIATED BEFORE RETRY.
  • Page 51 COOLING SEQUENCE OF OPERATION POWER ON SIGNAL POLARITY REVERSED. CONTROL WILL CONTINUE TO CALL FOR COOLING IS POLARITY REVERSED? IN THIS CONDITION. STATUS ERROR CODE 5 + 4. SIGNAL IMPROPER GROUND AT LED. CONTROL WILL CONTINUE TO CALL FOR COOLING IS THERE IN THIS CONDITION.
  • Page 52 CONTINUOUS LOW SPEED FAN SEQUENCE OF OPERATION MANUAL FAN SELECTION MADE AT THERMOSTAT. AFTER 2 SECOND DELAY, INDOOR BLOWER IS ENERGIZED ON CONTINUOUS FAN SPEED. THERMOSTAT CALLS FOR FIRST STAGE COOL. THERMOSTAT CALLS FOR FIRST−STAGE HEAT. INDOOR BLOWER RAMPS TO FIRST STAGE AFTER 45−SECOND DELAY, INDOOR BLOWER COOLING SPEED AFTER A 2−SECOND DELAY.
  • Page 53 VIII−Field Wiring & Jumper Settings A−SureLight Boards 18M99 and 49M59 Jumper Settings (See figure 4) Thermostat Wiring Connections W915 W914 W951 1 Heat / 1 Cool SINGLE Intact Intact Intact CONTROL OUTDOOR T’STAT TERM. STRIP UNIT NOTE − Use dip switch 3 to set second−stage heat ON delay.
  • Page 54 Jumper Settings (See figure 4) Thermostat Wiring Connections W915 W914 W951 1 Heat / 2 Cool SINGLE Intact CONTROL OUTDOOR CCB1 with CCB1 T’STAT TERM. STRIP UNIT NOTE − Use dip switch 3 to set second−stage HSXA19 heat ON delay. (LSOM) ON−10 minutes.
  • Page 55 Jumper Settings (See figure 4) Thermostat Wiring Connections W915 W914 W951 2 Heat / 1 Cool Intact Intact Intact CONTROL OUTDOOR T’STAT TERM. STRIP UNIT HSXB15 (LSOM) FM21 Heat Pump / 1 SINGLE Intact Intact CONTROL FM21 TERM. STRIP Cool *Disconnect existing furnace transformer and replace with 75VA,...
  • Page 56 B−SureLight Board 100870 Jumper Settings (See figure 5) W915 W914 Dehu- Two−Stage midification W951 Thermostat Wiring Connections DIP Switch 1 Cooling or Harmony Heat Pumps 1Heat / 1 Cool Intact Intact Intact CONTROL OUTDOOR T’STAT TERM. STRIP UNIT NOTE − Use DIP switch 2 to set second−stage heat ON delay.
  • Page 57 Jumper Settings (See figure 5) W915 W914 Dehu- Two−Stage midification W951 Thermostat Wiring Connections DIP Switch 1 Heat Pumps Cooling or Harmony 2 Heat / 2 Cool Intact Intact CONTROL OUTDOOR T’STAT TERM. STRIP UNIT 2 Heat / 2 Cool Intact CONTROL OUTDOOR...

  • Page 58: Ix Troubleshooting

    IX− Troubleshooting Two Stage Variable Speed Control Boards 18M99 & 49M59 UPON INITIAL POWER UP, REMOVE ALL THERMOSTAT DEMANDS TO THE UNIT PROBLEM: 1 UNIT FAILS TO OPERATE IN THE COOLING, HEATING, OR CONTINUOUS FAN MODE Condition Possible Cause Corrective Action / Comments 1.1.1 ACTION 1 −...
  • Page 59 PROBLEM 2: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR BLOWER DOES NOT ENERGIZE Condition Possible Cause Corrective Action / Comments ACTION 1 − Check continuity across switch(es). Switches reset automatically upon cool down. − Unit operates with a cooling or contin- 2.1.1 Rollout switch must be reset manually.
  • Page 60 PROBLEM 4: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR INDUCER ENERGIZES, IGNITOR IS NOT ENERGIZED. Condition Possible Cause Corrective Action/Comments 4.1.1 ACTION 1 − Check that the prove switch line is − Unit operates with a cooling and Prove switch does not close due to correctly routed.
  • Page 61 PROBLEM 5: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR BLOWER ENERGIZES, IGNITOR IS ENERGIZED. Condition Possible Cause Corrective Action/Comments ACTION 1 − Check line pressure at the gas valve. 5.1.1 Pressure should not exceed 13" WC for both nat- −...
  • Page 62 PROBLEM 6: BURNERS LIGHT WITH HEATING DEMAND BUT UNIT SHUTS DOWN PREMATURELY (CONT.) Condition Possible Cause Corrective Action/Comments ACTION 1 − Check that the manifold pressure matches value listed on nameplate. See installa- − Combustion air inducer energizes 6.3.1 tion instructions for proper procedure. with a heating demand.
  • Page 63 PROBLEM 6: BURNERS LIGHT WITH HEATING DEMAND BUT UNIT SHUTS DOWN PREMATURELY (CONT.) − Combustion air inducer energizes ACTION 1 − Check that the sensor is properly lo- 6.5.1 with a heating demand. cated. ACTION 2 − Check that the sense wire is properly Loose sensor wire connection causes −...
  • Page 64 Two Stage Variable Speed Control Board 100870 UPON INITIAL POWER UP, REMOVE ALL THERMOSTAT DEMANDS TO THE UNIT PROBLEM: 1 UNIT FAILS TO OPERATE IN THE COOLING, HEATING, OR CONTINUOUS FAN MODE Flash Code Possible Cause Corrective Action / Comments LED X + Y 1.1.1 ACTION 1 −...
  • Page 65 PROBLEM 2: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR BLOWER DOES NOT ENERGIZE Flash Code Corrective Action / Comments Possible Cause LED X + Y ACTION 1 − Check continuity across switch(es). 2.1.1 Switches reset automatically upon cool down. Unit operates with a cooling or ACTION 2 −...
  • Page 66 PROBLEM 4: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR INDUCER ENERGIZES, IGNITOR IS NOT ENERGIZED. Flash Code Possible Cause Corrective Action/Comments LED X + Y 4.1.1 ACTION 1 − Check for restricted vent. Remove all blockage. − Unit operates with a cooling and Prove switch does not close due to ACTION 2: Check for proper vent sizing.
  • Page 67 PROBLEM 5: UNIT FIRES ON LOW FIRE, FAILS TO GO TO HIGH FIRE OPERATION Flash Code Possible Cause Corrective Action/Comments LED X + Y 5.1.1 ACTION 1 − Check for restricted vent. Remove all blockage. − Unit light s normally during low fire Prove switch does not close due to ACTION 2: Check for proper vent sizing.
  • Page 68 PROBLEM 6: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR BLOWER ENERGIZES, IGNITOR IS ENERGIZED. Flash Code Possible Cause Corrective Action/Comments LED X + Y ACTION 1 − Check line pressure at the gas valve. 6.1.1 Pressure should not exceed 13" WC for both nat- Unit operates with a cooling and ural and propane.
  • Page 69 PROBLEM 7: BURNERS LIGHT WITH HEATING DEMAND BUT UNIT SHUTS DOWN PREMATURELY (CONT.) Flash Code Possible Cause Corrective Action/Comments LED X + Y ACTION 1 − Check that the manifold pressure matches value listed on nameplate. See installa- Combustion air inducer energizes 7.3.1 tion instructions for proper procedure.
  • Page 70 PROBLEM 7: BURNERS LIGHT WITH HEATING DEMAND BUT UNIT SHUTS DOWN PREMATURELY (CONT.) Flash Code Possible Cause Corrective Action/Comments LED X + Y ACTION 1 − Check that the sensor is properly lo- Combustion air inducer energizes 7.5.1 cated. with a heating demand. ACTION 2 −...
  • Page 71 ICM−2 WITH TWO STAGE VARIABLE SPEED CONTROL BOARD 120V to the motor must not be interrupted. All connections for check out will be from the volt- age source below (battery or 24V) to plug J46, after disconnecting from blower control board. REMOVE PLUG FROM BOARD CHECK−OUT PROCEDURE USING BATTERY CHECK−OUT PROCEDURE USING 24V SOURCE...

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