T011_F: Failed Ignition
Status
Up to 3 failed ignitions will not constitute a critical condition. Critical condition (with no gas heating operation) will only occur if the furnace has failed to ignite 4 times consecutively. When the furnace fails to ignite 4 consecutive times, the faults "10" and "11" will be displayed alternately.
Description
This code will be displayed after a failed ignition. Only when it happens 4 times consecutively, will it change to a one-hour lockout and display "10" and "11" alternately.
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. If the spark is weak, missing, or in the wrong location, the burners cannot light. Resolve the spark issue.
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.
