Front Air blowing hot!

[Angela1]

Finally got some hot weather in BC and now our front air is not working...it comes on and blows cold for about 5 minutes and then changes to hot! The bedroom air works fine. Been up on the roof and checked to make sure it wasn't blocked with debris . They are Duotherm low profile units. Any ideas would be welcome.
KSDP 3910

[deaton]

Wild guess time - but the most likely cause, from the symptoms you describe, is low coolant that is causing it to freeze up after the first few minutes of use. Others on this forum, I'm sure, can give you other suggestions.

[RVDude]

If you mean it's blowing HOT air (like 120+F) and not just ambient WARM air it's jumping into heat pump mode. Something awry on the internal control board is causing the unit's reverser valve to switch operation or maybe even the reverser itself. It might also be something crossing up in the thermostat wiring or the tstat itself causing it to switch into heat mode too, but I'd suspect the control board first.

If just ambient warm, can you tell if the compressor is humming away or does that stop humming when it goes into the warm mode? As I understand it, they don't use low refrigerant switches in these units anymore so something is causing the compressor to drop out.

You might take the top off and jiggle the wiring on the control board (do while it is OFF and the RV is unplugged please).

[Angela1]

Thanks for your input...it does sound like it may be the control board. It is way to hot to go up on the roof and check things out further right now so i guess we will have to leave it until next week when it is supposed to be cooler!