Lennox International Inc G24-200 Troubleshooting, Normal Heating Mode, Abnormal Heating Mode

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Troubleshooting

Troubleshooting

HEATING SEQUENCE OF OPERATION WITH TWO-STAGE THERMOSTAT

NOTE − THIS FURNACE FUNCTIONS WITH TWO INDEDPENDENTLY CONTROLLED HEAT SECTIONS. THE GRAY BOXES INDICATE COMPONENTS WHICH EFFECT BOTH HEAT SECTIONS SIMULTANEOUSLY.

NORMAL HEATING MODE

POWER ON

THERMOSTAT CALLS FOR HEAT

(W1 ENERGIZED)

K13 RELAY ENERIZED.

A3 (A12) IGNITION CONTROL LED ON.

IS THE S10 (S99) HIGH LIMIT CLOSED?

YES

IS THE S47 (S69) ROLLOUT SWITCH CLOSED?

YES

IS THE B6 (B15) COMBUSTION

AIR BLOWER ON?

YES

IS THE S18 (S45) COMBUSTION AIR BLOWER PROVING SWITCH CLOSED?

YES

B6 (B15) COMBUSTION AIR BLOWER

PREPURGE FOR 30 SECS.

8 SEC TRIAL FOR IGNITION − START IGNITION TRAIL, GV1 (GV3) GAS VALVE OPENS ON LOW HEAT. IS FLAME SENSED WITHIN 8 SECS?

YES

K56 (K57) RELAY ENERGIZED. K25 CIRCUIT BOARD ENERGIZED. SYSTEM BLOWERS ON AFTER 45 SEC DELAY.

YES NORMAL HEATING MODE

FLAME SENSE OK?

YES

CONTINUED NEXT PAGE

ABNORMAL HEATING MODE

 

 

NO

DETERMINE WHY AUTOMATIC-RESET

 

 

 

 

 

 

S10 (S99) HIGH LIMIT OPEN.

 

 

 

 

 

 

 

 

 

 

 

NO

CHECK VENTING SYSTEM

 

 

 

 

 

 

OPERATION/BLOCKAGE BEFORE

 

 

 

 

 

 

 

 

 

 

 

 

RESETTING THE MANUALLY-RESET S47

 

 

 

 

 

 

(S69) ROLLOUT SWITCH.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NO

CHECK K13−1 CONTACT OPERATION AND

 

 

 

 

 

 

WIRING TO B6 (B15) COMBUSTION AIR

 

 

 

 

 

 

 

 

 

 

 

 

BLOWER?

 

 

 

 

 

 

 

 

 

 

 

NO

CHECK SENSING TUBE FOR BLOCKAGE

 

 

 

 

AND S18 (S45) SWITCH FOR PROPER

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OPERATION.

 

 

 

 

 

 

 

 

 

 

 

 

 

NO

 

 

 

 

 

 

 

 

GV1 (GV3) GAS VALVE CLOSED, SPARK

NO

OFF. INCREMENT TRAIL REGISTER.

 

 

(DURING RETRY PERIOD LED FLASHES

 

 

 

 

.5 SEC. ON AND 2.5 SEC. OFF. ARE THE

 

 

THREE TRIALS COMPLETE?

 

 

 

 

 

 

 

 

 

 

 

YES

 

 

 

 

 

 

 

LOCKOUT OCCURS. TO RESET A3 (A12)

IGNITION CONTROL MOVE THERMOSTAT

SWITCH FROM HEAT TO OFF TO HEAT.

NO

CHECK BELT.

CHECK RELAYS.

NO

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Contents INSTALLATION INSTRUCTIONS G24-200 2P0805P504613M WHAT TO DO IF YOU SMELL GASG24−200 Unit Dimensions − inches mm PageG24−200 Filter Box Dimensions − inches mm SIDE VIEWBACK VIEW TOP VIEWG24−200 HEAT SECTION AND CABINET G24−200 Parts ArrangementPage G24−200 BLOWER SECTION G24−200 Parts Arrangement ContinuedPage G24−200 Gas Furnace SafetyShipping and Packing List setting General Combustion, Dilution & Ventilation AirCements and glues EQUIPMENT IN CONFINED SPACE ALL AIR FROM INSIDE Setting Equipment Return Air Plenum / Filter Box InstallationBOTTOM RETURN AIR FILTER BOX INSTALLATION PageBlower Motor / Drive Installation Duct SystemVenting Venting Using a Masonry Chimney Page Page SERVING A SINGLE CATEGORY I APPLIANCE PageSERVING A SINGLE CATEGORY I APPLIANCE PageVENT CONNECTOR CAPACITY SERVING TWO OR MORE CATEGORY I APPLIANCESSERVING TWO OR MORE CATEGORY I APPLIANCES COMMON VENT CAPACITYPage CARBON MONOXIDE POISONING HAZARD VENT TERMINATION CLEARANCES FOR INSTALLATIONS IN THE USA AND CANADAPage Horizontal Venting Gas Piping FIRE OR EXPLOSION HAZARD Electrical G24−200 FIELD WIRING DIAGRAM 120V SINGLE PH 60HZ Alternate make-upbox right side Alternate make-upG24-200FIELD WIRING DIAGRAM G24−200 FIELD WIRING DIAGRAM G UNITS − 460V 3PH 60HZJ UNITS − 575V 3PH 60HZ Alternate make-upFIGURE Page WIRING SCHEMATIC DIAGRAM FOR G24−200 P UNITS − 208/230V 1PH 60 HZY UNITS − 208/230V 3PH 60HZ G UNITS − 460V 3PH 60HZUnit Start−Up Heating Sequence of Operation Other Unit Adjustments and Operation Gas Pressure AdjustmentHigh Altitude Information Temperature Rise Setting blower CFM TABLE DRIVE KIT SPECIFICATIONS TABLE ACCESSORY AIR RESISTANCEPage Repair Parts List G24−200 Start−up and Performance Check ListTroubleshooting NORMAL HEATING MODEABNORMAL HEATING MODE Page3 − OFF NO POWER OR DETECTED FAULT NORMAL HEATING MODEABNORMAL HEATING MODE LED CODESPOWER ON THERMOSTAT CALLS FOR HEAT W1 ENERGIZED IS THE S10 S99 HIGH LIMIT CLOSED? YES COOLING SEQUENCE OF OPERATION FOR TWO CONDENSING UNITSFOR A SINGLE CONDENSING UNIT MANUAL FAN OPERATION