Heat Pump/AC won't stop running unless circuit breaker turned off - any ideas?

Hi -

We have a 2350  model year 2010.  We have a new problem with the AC / heat pump on our last trip to Florida.  When we turn off the AC or Heat Pump, the unit still runs.  It is not the fan that is running, but there is a hum from the unit regardless of whether we have the Heat Pump or AC unit on.

The only way to stop the humming noise is to shut off the circuit breaker.  When the circuit breaker is turned back on, with the thermostat switch still in the off position, the noise starts immediately though the fan is not blowing.

We have looked at the forum for suggestions and have re-seated all of the wires going into the thermostat control.  We have also tried changing the fan switch from on to auto.

Can anyone provide some suggestions on things to try?  Thanks in advance! 

Katlin

Take it to a dealer is my suggestion.   Nothing should be running with the thermostat in the off position.

A new thermostat is less than $100. Might be worth a try.

Not sure of your mechanical ability, but the first thing to find out is WHAT is making the humming? This requires hands-on time, but novice level stuff.

The top cover and probably an insulation piece (or several...) should be removable without major issues. This may allow you to track down the hum, and/or determine what is NOT humming. Would be nice to know its not the compressor, fan or other $$$ piece. 

If you can, post the make/model of your AC/heat pump. Proper diagnostics begin with good baseline info.

 The hum might be as innocent as a 120V-24V transformer that is a bit loose. That would be an item that could be on all the time independently of the thermostat status. There may be gas solenoid(s) that are in a 'locked on' state when the unit is on standby that are vibrating. OR a latching relay that isnt quite latching.

 My RV has the old 'resistor-style heat strip'  not a heat pump. No wall thermostat control, just the knobs on the unit itself. I would have to see a schematic of your heat pump unit to see if there are any other likely suspects for a 'power-on hum'  beyond these guesses.

Again, after reading all of the above, I would strongly recommend you take the RV to an RV shop to diagnose the issue.  It's not the thermostat since a thermostat is either on or off.  It may be a relay that is stuck, it may be a transformer that is loose and it may be lots of other things.  There is nothing else in the area of the roof that will turn on/off with the a/c breaker except the a/c unit itself.  A diagnostic fee (should be about a half hour labor fee, but that varies) is typically a good way to find the trouble.   Many (but certainly not all) shops waive the fee if you get the unit repaired there.

Don is right, should you not be inclined to get up on the roof, or not ready to tear into the AC, get to a shop! Around here 1 hr is standard minimum for labor, and for this type of problem usually finding it is most of the job towards fixing it anyway. So the diagnostic time HOPEFULLY will turn into repair time as it progresses.


I am one of those freaks that takes everything broken apart... and fixes most of them!      Its an addiction. I just like to know how everything works.