Goodman Furnace: High fire and low fire gas pressure test (longer term)
High fire and low fire gas pressure test (longer term) on a Goodman furnace: Forces a continuous high fire or low fire run using thermostat W. Remove the communicating or RJ12 connection first as described.
Applies to: Gas pressure test, high and low fire
How to fix high fire and low fire gas pressure test (longer term): step by step
- Turn the furnace off.
- On a communicating fossil fuel system, remove or disconnect anything on terminals 1, 2, R and C. With a non-communicating heat pump module, unplug the RJ12 jack.
- Power the furnace.
- High fire: apply a W call. The system runs continuously at 100% firing. Remove W to shut down.
- Low fire: apply W, let ignition start, then remove W so the furnace enters idle (display shows IdL).
- Apply W again. Low stage runs for more than 5 minutes if the target run time is set above 10 minutes.
- Remove W to shut down when done.
If the unit shows an error code, look it up: Goodman Furnace codes
More service & test modes tips for furnace
Source: Goodman GMVC96 service manual, p. 52. 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.