Lennox International Inc. G24-200 - Manual (Page 43)

Page 43
HEATING SEQUENCE OF OPERATION WITH SINGLE-STAGE THERMOSTAT CONTINUED
NORMAL HEATING MODE ABNORMAL HEATING MODE
DETERMINE WHY AUTOMATIC-RESET
S10 (S99) HIGH LIMIT OPEN. K20, (K123), K36
RELAYS MAINTAIN BLOWER OPERATION.
IS THE S10 (S99) HIGH LIMIT CLOSED?
IS W1 DEMAND OF
THERMOSTAT SATISFIED?
A3 (A12) LED OFF
YES
B6 (B15) COMBUSTION
AIR BLOWER OFF.
B3 SYSTEM BLOWERS OFF
AFTER 150 SEC DELAY.
NO
YES
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.
SECOND-STAGE OF GV1 (GV3)
GAS VALVE CLOSES AFTER
APRROXIMATELY 3 SEC. AND
THEN FIRST-STAGE CLOSES.