I had an Atwood acnd with heat pump installed also. My heat pump runs but will never warm up our coach. It cycles on til the outlet temp gets to about 100° then shuts off. Fan runs about 5 seconds every minute for 2 minutes to get the the temp from someplace, return air I think, then comes on again until outlet temp gets to 100° when it shuts off and repeats the cycle. It will never warm the coach. The installer has been working on it off and on for a year trying to get it to work. It is absolutely great on cooling, but a sorry pos on heat.