Condition
Furnace Lights Then Shuts Off
Burner ignites briefly then shuts down. Flame sensor or limit switch.
Possible Causes
Oxidized Flame Sensor
Soot buildup on the sensor causes it to lose its ability to detect the flame, shutting down the furnace.
Root Cause Analysis →Diagnostic Tests
- Inspect for oxidation
- Clean with steel wool
- Check microamp reading
Repair Options