if the outside temp is below 40 degrees the heat pump will not work. It will only blow out cold air.
i wonder why that is? doesn't that defeat the purpose?
also I believe the heat pump will not turn on if the thermostat is set more then 4* warmer then the current temp inside the coach. If its below 40* outside then your only getting the furnace on propane. fire place , cube heaters and some propane is about all you can do once its below 40*f