A113_F: One-Hour Lockout: Ignition Failure
Status
The furnace attempted ignition 4 times but failed to prove flame before locking out for one hour.
Description
If flame is not established during a trial for ignition, the IFC de-energizes the gas valve, and igniter immediately. A strike counter is incremented, and the induced draft motor remains energized for an inter-purge period of 10 seconds followed by a new ignition attempt. This cycle repeats for up to 4 times in an attempt to establish flame. If flame is not established on the fourth ignition attempt, the control performs a 10 sec inter-purge and then post-purge. At the start of post purge, the IFC enters a one-hour “soft” lockout and declares alarms “A113_F One-hour Lockout: Ignition Failure” and “A011_F Failed Ignition”. Once the one-hour lockout ends, both the “A113_F One-hour Lockout: Ignition Failure” and “A011_F Failed Ignition” alarms are cleared and normal operation resumes.
Cause
There can be several causes for ignition failures.
1. The flame sense rod is not detecting flame. It may need cleaned or is not properly connected.
2. The gas valve may be turned off.
3. The igniter is not working properly.
4. The furnace control may not be working properly or is not properly grounded.
5. The flame is not properly spreading from the first burner to the last.
6. The face of the burner is dirty or corroded, or the flame is lifting off the burner nozzle.
Solution
The solution may depend on the cause.
1. If the flame sense rod needs to be cleaned, remove it and clean the rod with steel wool. Do NOT use sandpaper. Check the connections all the way back to the IFC.
2. If the gas valve is off, turn it on. Check inlet gas pressure to ensure gas is available to the furnace.
3. 3. If the spark is weak, missing, or in the wrong location, the burners cannot light. The igniter rod may need to be fixed/replaced or the control board may need to be replaced.
4. Verify the IFC is properly grounded. Temporarily connect a jumper from C to the furnace chassis. A solid earth ground must be present in order for flame rectification to work. Check voltage from Neutral to ground and verify there is no voltage present.
5 and 6. If the flame is not spreading to the last burner, remove the burners and clean them. Do not spread the crossovers. A dime should fit loosely between the spreaders, a nickle will be a snug fit.
