Atwood Heat Pump

to Bob Vaughn: I can double check, but I am fairly certain that the book does not say that the furnace will not operate until 45 degrees. The furnace will operate if the heat pump does not satisfy the heat needed within some timeout. It is very short. So the furnace kicks in and begins to heat. When the heat pump is ready, it will begin to operate and the heat pump's thermostat will take control away from the furnace so that it will shut off again (it has an automatic run time requirement in the furnace) so they will both be running at the same time for awhile. But if you don't feel significant heat - like 80 to 90 degrees coming out of the unit, it isn't working right. At least that is what my atwood puts out. What the book is saying is that the furnace is operated under 45 degrees - the heat pump is shut off. But my experience is that it will operate between the furnace and the heat pump to under 40 degrees, but then it has to deice itself quite often. There are two 'furnace' operations - one in conjunction with the heat pump similar to aux heat on a hvac system and one that is separate where you actually do not use the a/c at all, but it turns over operation to the furnace when you switch the 'furnace' to on.

Don't worry about the fan running, let it run. If it doesn't shut off, then there is something wrong. If it continues to heat until you are baked out, then your system is either set up wrong or you switched the 'Furnace' switch on - it must be off. Use 'Furnace' only if you want the Atwood to not run the furnace temp.