Goodman Furnace: Checking unit grounding
Checking unit grounding on a Goodman furnace: Before you trust any electronic control on this Goodman furnace, confirm it has a solid ground. The gas piping must never be used as the electrical ground, so the path has to run through the furnace ground screw and the supply wiring back to the panel. Do this check with the power off, and call a licensed electrician if the ground path is in doubt.
Applies to: Gas furnace
Common causes of checking unit grounding
- A missing or broken ground wire between the junction box and the panel
- A loose or corroded ground screw connection
- A poor connection from the neutral side to the burners, which raises the resistance reading
How to fix checking unit grounding: step by step
- Shut off the electrical power at the disconnect and confirm it is dead with a meter before touching anything.
- Measure resistance between the neutral (white) connection and one of the burners.
- Confirm the reading is 10 ohms or less.
- Trace the ground wire from the furnace ground screw in the junction box back to the electrical panel and confirm it is continuous.
- Tighten or clean any loose or corroded ground connection and recheck the reading.
- If the ground path cannot be proven, have a licensed electrician correct the wiring before returning the furnace to service.
If the unit shows an error code, look it up: Goodman Furnace codes
Source: Goodman GMVC96 service and troubleshooting manual, p. 25. 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.