I have a Carrier gas furnace.
For some reason, when I switch it on via thermostat, it SOMETIMES turns on, but SOMETIMES, it gets stubborn and refuses to turn on.
These are the symptoms:
- When it's working, it seems to work ok. It turns off when it reaches the right temperature, then turns back on when it cools down. It works fine like this all day.
- Other times, it just won't turn on. No matter how much I switch the thermostat on/off, the furnace won't turn on.
- Even when the furnace won't fire up, I can turn on the fan.
- I took off the air filter. It was very matted with dust, but I pulled off 95% of what I see. I'm sure there's invisible dust on there, but is that enough to prevent the furnace from turning on?
- Sometimes, it won't work for an entire day, and the next morning, it turns on (via the scheduler on the thermostat). I didn't need to touch anything.
- This morning, it refused to turn on again. I went downstairs, and checked the door was fully closed and tightend. The doors looked ok. Then, I flipped the power switch on/off, then nudged the air filter to see if it was all the way in. Within seconds, the furnace powered back on.
Does this sound like a correct diagnosis?:
- Thermostat is probably ok.
- gas, and pilot is probably working.
- Since it turned on by nudging the filter and flipping the power on/off, it's PROBABLY one of those two?
- I'm guessing it's NOT the electrical, since I can always turn on the fan?
I'm guessing replacing the filter is probably the cheapest thing to try first, THEN maybe call an HVAC person or electrician?
Thanks. I would like to eliminate the simple solutions before paying someone to inspect, so any input would be welcome.