Lennox G21Q3-80

Page 57
VII − TROUBLESHOOTING FLOWCHARTS
IGNITION CONTROL CHECKOUT GC1
REPLACE
GC1 CONTROL
APPLY THERMOSTAT DEMAND
AND ALLOW UNIT TO IGNITE
AND ESTABLISH FLAME.
DOES THE CONTROL HALT OPERATION AND
LED LIGHTS IMMEDIATELY AFTER THE TRIAL
FOR IGNITION (WAIT 2 MINUTES TO MAKE SURE
UNIT IS OUT OF POST  PURGE
NO YES
TURN OFF UNIT POWER AT DISCONNECT
FOR AT LEAST 3 SECONDS, THEN TURN
POWER BACK ON. ALLOW 3 SECONDS
FOR CONTROL TO POWER−UP.
IS RED DIAGNOSTIC
LED LIT?
UNIT WAS
IN LOCKOUT
LIT
YES
CONTROL SHOULD OPERATE
PROPERLY PROCEED TO UNIT
WILL NOT RUN"−GAS CHECKS
AND SPARK CHECKS TO RULE
OUT OTHER POSSIBILITIES.
NO
CONTROL SHOULD OPERATE
PROPERLY PROCEED TO
ELECTRICAL CHECKOUT.
NOT LIT
REPLACE GC1
CONTROL
START HERE
IS RED DIAGNOSTIC
LED LIT?