HVAC question

Little cool yesterday so I tested my heat pump on a little park model trailer, separate from my house. Condenser ran but blew cold air, turned it to Off on the T-stat. I just thought I’ll have to look at that when the times right. Went down to it this morning and it was over 100 degrees in there with hot air coming out of the vents. Couldn’t shut it down at the thermostat, had to go flip the breakers. Obviously has Elements somewhere ( auxiliary heat ). Anyone experienced something like this ? Gotta go cut some wood so I won’t be able to reply ‘til later.

You may have done some major damage . Once the thermostat turns off the elements the fan must blow until it cools them . Just like an over head projector. MAYBE you didn't burn out the element.

I had something similar happen, a mouse had chewed the thermostat wiring, shorted the wiring, and thermostat no longer was in control.

There is a small thermal circuit breaker that could go bad. they have a high and low limit. May be thermostat also. What model is it. I have a amana ptac unit in my patio room that did that . It was the low limit sensor.
Same thing on a clothes dryer.

Have you tried replacing the thermostat?
Or,,,,, maybe it is hooked up wrong?

Or we talking about a stand alone unit like or one with a exchanger?

Planning on changing it, first thing I’ll check the batteries . Could be hooked up wrong, I changed it out earlier this Summer. I have to tunnel under to access the Air handler or whatever it’s called. Thanks guys for the ideas, it’s a start.

Start with the wiring configuration. Reversing valve. Sounds like to me. That is where I would start. Some power the reversing valve from cooling W. Some from heatY . Make sure your thermostat has the B hooked up. That energizes your reversing valve

Thanks Pete, that is now on the list .