I have a two story house with two air conditioning units. One for the upstairs and one for the downstairs. I rarely if ever use the upstairs unit because the master bedroom is downstairs and no one lives upstairs.

I had some company in town the other day and when we cut the air on it ran fine. The next day I noticed that the fan was still running on it and it was blowing air but not cold air. I switched the thermostat to the Off position and the fan continued to run. The only way I could get the fan to stop running was to trip the circuit breaker for the unit. I thought that the thermostat may be bad so I switched with another one I had here at the house. When I flipped the breaker back on the fan started right up just as before. I'm not sure how the fan can run like that when the thermostat is set to Off and the fan setting is set to Auto.

I went up in the attic to see if I could find some kind of reset switch on the air handler but I didn't see anything. If anyone has any ideas on what's going on that would be great! This unit is rarely used so I know its not worn out, but maybe that's part of the problem.

Thanks in advance for your help!!