Goodman furnace F: Continuous fan
F means the blower is running continuously without heating or cooling. It is normal, and it is usually because the thermostat's fan setting is on rather than auto.
Applies to: Goodman GMVC96, GMVM97, GCVC96, GCVM97 and Amana AMVC96, AMVM97 series gas furnaces with a two-character alphanumeric display.
What it means
Continuous fan circulates air without heating or cooling it, which some people use deliberately for air filtration or to even out temperatures between rooms. The display shows F while it is happening. It is worth recognising because a blower that runs constantly is one of the more common things people phone about, and on a modern variable-speed furnace continuous fan is quiet and cheap enough that it can run for weeks unnoticed until someone looks at an energy bill or hears it at night.
Most common causes
- The thermostat's fan setting is on rather than auto. This is the usual explanation.
- A continuous fan schedule configured in a smart thermostat.
- A whole-house filtration or ventilation strategy that calls for continuous circulation.
- A thermostat wiring fault energising the fan circuit permanently.
- A zone control or ventilation system calling for circulation.
How to diagnose it
- Check the thermostat's fan setting first — on rather than auto is the answer in most cases.
- Check for a scheduled fan setting in a smart thermostat's app, since these are easy to enable and forget.
- Note whether the blower stops when the fan setting is changed to auto. If it does, nothing is wrong.
- If the blower continues with the thermostat set to auto and no heating or cooling demand, that is a wiring or control issue.
How to fix it
- Set the thermostat's fan to auto if continuous circulation was not intended.
- Check any scheduled circulation settings in a smart thermostat.
- If the blower will not stop with the fan set to auto, that needs a technician — the fan circuit is being energised by something.
- Nothing needs fixing if continuous fan is deliberate. It is a legitimate way to run the system.
Notes
Continuous fan on a variable-speed furnace runs at a low speed and uses very little power compared with an older motor, which is exactly why it can run unnoticed for a long time. That is a feature rather than a fault.