How can my furnace exhaust fan run with the power off, the thermostat off, and the breaker off?!
Some furnaces have more than one breaker
Well, most honestly.
- The Air Conditioning unit has a breaker
- If present, electric heating elements (e.g. emergency heat) have one or more breakers
- The blower will have its own breaker, typically shared with the electronics on a gas furnace
- A built-in humidifier or dehumidifer may have its own breaker
- Depending on location, the 24V thermostat transformer may be on yet another breaker
Unrelated, the radon venting system has its own breaker.