Air handler will not turn off?

[Rookiehandyman]

My family and I just returned from vacation and we noticed that it was alittle warm in our home but just thought it was the warmer weather we had that day. The nights have been cool, so we opted not to bother the setting on the thermostat. About 2 days later, my wife told me the reason it had been warm is because the heat was running. I went under the house and heard the air handler was running indeed.

I came back in to insure that both the heat and cooling setting were set to off. Both were in the off postion, but air was being pushed through the vents. Because it was getting to be too hot inside, I cut the circuit breaker off. I turned the circuit breaker on again yesterday, but it continues to do the same thing.

I did check to see if the air conditioning unit would come on if the thermometer was set correctly and it did.

My heat pump is underneath my home and was just installed 2 years ago. It is a Rheem unit, model RBCA 6089G. My air conditioning unit is an American Standard and is only 3 years old. My thermostat is a rather old one and not sure of the type.

What would be the most likely problem I need to address?

Thanks for your help!

[HayZee518]

one or two things. the contactor that runs the fan could be welded shut or the limit is adjusted too low.