Lennox International Inc G24-200 Normal Heating Mode, Abnormal Heating Mode, Led Codes, Page

HEATING SEQUENCE OF OPERATION WITH TWO-STAGE THERMOSTAT CONTINUED

NORMAL HEATING MODE ABNORMAL HEATING MODE

IS THE S10 (S99) HIGH LIMIT CLOSED?

YES

HAS ROOM AIR TEMPERATURE CONTINUED

TO DROP BELOW THE THERMOSTAT"S

W2 SET POINT?

NO

DETERMINE WHY AUTOMATIC-RESET S10 (S99) HIGH LIMIT OPEN. K20, (K123), K36

RELAYS MAINTAIN BLOWER OPERATION.

YES

POWER FROM W2

ENERGIZES K19 RELAY

SECOND-STAGE OF GV1 (GV3)

GAS VALVE ENERGIZED (HIGH HEAT)

AFTER APPROXIMATELY 3 SEC.

IS W2 DEMAND SATISFIED?

YES

CLOSE SECOND-STAGE OF GV1 (GV3) GAS VALVE AFTER APPROXIMATELY 3 SEC. AND THEN RETURN TO LOW HEAT OPERATION.

NO

IS W1 DEMAND SATISFIED?

YES

A3 (A12) LED OFF

FIRST-STAGE OF GV1 (GV3)

GAS VALVE CLOSES.

B6 (B15) COMBUSTION

AIR BLOWER OFF.

B3 SYSTEM BLOWERS OFF

AFTER 150 SEC DELAY.

NOTE − IF ECONOMIZER INSTALLED, ECONOMIZER OPERATES WHEN BLOWER POWERED.

LED CODES

1 − ON NORMAL OPERATION WITH THERMOSTAT CALLING FOR HEAT. 2 − 0.5 SEC ON AND 2.5 SECS OFF IN IGNITION RETRY PERIOD.

3 − OFF NO POWER OR DETECTED FAULT.

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