Goodman Furnace: Loss of flame after establishment
Loss of flame after establishment on a Goodman furnace: Burners light, then drop out. Flame is established and then it is gone. Often a few seconds later it tries again. Look at what changes right after light off: gas, draft, or flame sensing. Start with the easy stuff.
Applies to: 34.5 in chassis gas furnaces
Common causes of loss of flame after establishment
- Interrupted gas supply
- Lazy burner flames from improper gas pressure or restriction in flue and/or combustion air piping
- Front cover pressure switch opening
- Improper induced draft blower performance
- Coated or oxidized flame sensor
- Weak or poorly aligned igniter
How to fix loss of flame after establishment: step by step
- Locate and correct the gas interruption. Gas work is for a licensed gas tech
- Check front cover pressure switch operation (hose, wiring, contacts). Correct if needed
- Replace or realign the igniter
- Check the flame sense signal. Sand the sensor if coated or oxidized
- Check flue piping for blockage, proper length, elbows and termination
- Verify proper induced draft blower performance
- Watch the flame on a full trial. Note whether it goes out before or after the inducer changes speed
If the unit shows an error code, look it up: Goodman Furnace codes
Source: Goodman GMVC96 Service and Troubleshooting, p. 60. 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.