Re: ATF: Landmark - Heater System
On our Key West there are two Dometic controllers in the hallway, one above the other. With the top one you turn it on and then using Mode you can step through its features (fan, AC, HP, Furn); the lower one has the same set up less the HP (Heat Pump). I had the heat pump on first and the furnace never came on. Turned the top Dometic controller off and the furnace fired right up and heated very well.
Greg brought up an interesting point; just like a B&S heat pump unit, the colder the outside air gets, the less efficient the heat pump gets. I'm not sure of the point when the Dometic stops but on my American Standard home unit, it will run at -10F (belief is that even at that cold of a temperature that there is still some heat that can be pulled from the air -- scientifically, possibly, personally -- it is too dang cold to even worry about it). The inside auxiliary heat kicks on at 20 or so degrees regardless.
Now, if you are planning any forays into temperatures below freezing, you MUST have the furnace running to get heat into the belly. I've seen a lot of posts over the years where people use ceramic space heaters in the coach (even the fireplace heater at times
) but those do nothing for heating the belly and keeping the tanks and water lines a bit warmer. Their later posts describe some of the fun that they have had thawing things out. Personal experience - it does not take long at minus anything to freeze up water lines and fresh water tank. Seemed to take a whole lot longer to thaw than to freeze. Rough lesson learned.