Furnace ignition retry and lockout

What happens, in order

1. If flame is not detected within 7 seconds of the gas valve opening, the gas valve closes and a retry begins
2. Flame lost for 2 seconds during the 10 second stabilization period also starts a retry
3. During a retry the vent motor runs a 15 second inter-purge and the ignitor warm-up is lengthened to 27 seconds
4. Flame held for more than 10 seconds after a retry clears the retry counter
5. Three retries in one call for heat the furnace shuts down for one hour (7 red flashes), then starts a normal cycle if heat is still called for
6. Flame lost during burner operation is sensed in about 1 second; gas valve closes and the control recycles after a 15 second inter-purge
7. Five flame losses (four recycles) in one call: 60 minute lockout (8 red flashes)
8. Pressure switch opening four times in one call: one hour lockout (6 red flashes)
9. A power loss of 50 ms or longer closes the gas valve; on return the ignition sequence restarts immediately
10. Soft lockout resets itself after one hour; hard lockout needs power off and on

Timings and thresholds

Codes you may see during this

7 red flashes 8 red flashes 6 red flashes 1 red flash 10 red flashes

Models

More York furnace sequences

• Furnace heating cycle · Heating