A/C starts running when furnace kicks on

[ginger2000]

I am not sure if this is normal. I just purchased a new fifth wheel. When I turn the thermostat to heat the A/C unit kicks on as well as the furnace. The AC is pumping out cold air and is competing with furnace. It does not seem right to me. Please advise.

Thank you,

[Paddler]

Hi Ginger,
I'm no expert so take anything I post with a grain of salt. I agree with you, the AC should not be running when you have set the thermostat for heat. Now, one possible explaination might be...your thermostat thinks you have a heat pump/AC unit? You might want to check your circuit breakers to see if a breaker marked heat pump has tripped. (Assuming there is a seperated breaker for the aux heating strip) If not, a temporary fix would be the turn off the circuit breaker for the AC unit, until you can take the RV to a dealer. Oh if you tell us the make and model of your RV, maybe someone else has one and can be more helpful.
Best wishes,

[hankaye]

Ginger, Howdy;

A few more specifics would also be helpful...
in addition to what year , make, model, etc...

How long have you owned the trailer?

If a new one you should talk to the dealer, if used, well, you have found a place where there are quite a few knowledgeable folks here that may be able to help you along.

Remember, the more information you give us the better we can help YOU.

hankaye

[MILBY]

I bought my 327 year and had the same thing. There is a setting on the thermostat that will solve this just find the directions and it says how to do this. In the mean time I just shut off the breaker for the A/C.

[Handysam]

My guess would be that you have your fan setting on low or high, not auto. Auto needs to be set in order for the thermostat to recognize if you want heat or A/C. I'm assuming you have the same thermostat as me, the Dometic. Just a thought. Happy Camping, Sam

[Johnnyfry]

The system in my 318SAB acted the same way. The AC compressor did not come on, only the blower. I do not have either heat pump or Aux resistance heat in the AC unit.

After fiddling with the Dometic digital thermostat I found that this only happens with certain settings and is apparently a "feature" rather than a problem issue.

When I had set the blower to High or Low I had the problem, when it was set to auto it worked fine.

John

[ksfis43]

Originally Posted by Handysam

My guess would be that you have your fan setting on low or high, not auto. Auto needs to be set in order for the thermostat to recognize if you want heat or A/C. I'm assuming you have the same thermostat as me, the Dometic. Just a thought. Happy Camping, Sam

I had the same problem this weekend and switching to AUTO fixed it.

[azr405]

We had the same problem when we picked our 327 up this weekend. There apparently is a heat tape or something like that in the A/C and to stop the operation of the A/C unit you must switch to Auto. There is heat coming from the A/C but not a great deal and it is quite noisy.

[Johnnyfry]

Looking at the install manual it appears that some AC units (not mine) are equipped with an aux heating element ( not to be confused with a heat pump option) to allow the AC unit to do some level of heating (about 1.5kW or roughly 5,000 BTU/hour).

I do not know if this is a factory option or if it can be retrofitted.

This might explain the unexplained AC blower operation when heating.

John