Goodman Furnace: High stage pressure switch stuck closed at start of heating
High stage pressure switch stuck closed at start of heating on a Goodman furnace: The furnace runs fine on low stage but won't go to high. The high stage pressure switch is reading closed at the start of the cycle when it should be open, so the board won't bring on high fire.
Applies to: 34.5 in chassis gas furnaces
Common causes of high stage pressure switch stuck closed at start of heating
- High stage pressure switch contacts sticking
- Shorts in pressure switch circuit wiring
How to fix high stage pressure switch stuck closed at start of heating: step by step
- Turn power off before repair.
- Disconnect the switch leads and check across the switch with a meter. It should be open with the inducer off.
- Replace the high stage pressure switch with the correct part if the contacts are stuck.
- Repair the short in the wiring if the switch itself checks out.
- Restore power and run the furnace on both stages.
If the unit shows an error code, look it up: Goodman Furnace codes
Source: Goodman GMVC96 Service and Troubleshooting, p. 61. 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.