Goodman Furnace: Flame sensor cleaning and signal check
Flame sensor cleaning and signal check on a Goodman furnace: Dirty flame sensor. Fuel or air supply leaves a nearly invisible film on the rod. It insulates the rod and drops the flame signal. Qualified servicer cleans it with steel wool, gently. Then check the sensor output against the spec sheet.
Applies to: All 34.5in chassis gas furnaces
Common causes of flame sensor cleaning and signal check
- Insulating film on the flame sensor from fuel or combustion air cuts the signal
- Sensor rod bent or out of the flame path after handling (check when reinstalling)
How to fix flame sensor cleaning and signal check: step by step
- Power off at the disconnect. Let the burner area cool.
- Remove the flame sensor carefully, don't bend the rod.
- Clean the rod with steel wool until bright. No emery cloth that leaves grit.
- Reinstall the sensor in the same position, tighten the mounting screw.
- Power up, run a cycle, check flame sensor output against the spec sheet.
- Signal still low after cleaning? Look at burner flame and sensor wiring.
If the unit shows an error code, look it up: Goodman Furnace codes
Source: Goodman GMVC96 service and troubleshooting manual, p. 39. Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.