Codes for the 903106 integrated control board
CONTROL LIGHT STATUS
Steady ON Control OK
Steady OFF No power
Rapid Flash - False flame or gas valve relay shorted
1 Flash - Limit circuit open or external load on "W"
(does not apply to deck switch, see below)
2 Flashes - Pressure switch is open with inducer on
3 Flashes - Pressure switch is closed with inducer off
4 Flashes - Ignition failure (check ground)
5 Flashes 115 vac & neutral reversed or no ground
Steady ON - Good flame signal
Blinking - Weak flame signal
Steady OFF - No flame signal
for G3, G4, G5, G6, M2 & M3 Furnace Models.