34 IGNITION PROVING FAILURE - Control will try three more times before lockout
#14 occurs. If flame signal lost during blower on-delay period, blower will come
on for the selected blower off-delay. Check for: - Control ground continuity
- Flame sensor must not be grounded
- Oxide buildup on flame sensor (clean with fine steel wool).
- Proper flame sense microamps (.5 microamps D.C. min., 4.0 - 6.0 nominal).
- Gas valve defective or gas valve turned off - Manual valve shut-off
- Defective Hot Surface Ignitor
- Low inlet gas pressure
- Inadequate flame carryover or rough ignition
- Green/Yellow wire MUST be connected to furnace sheet metal
Cleaned the flame sensor and cleaned the igniter. No dice.
The igniter is not an arcing type, it appears to be a resistive element. It appears to have a defect in it. I'm going to check on ordering one.