Not sure I understand the rear electric heat

[kmx888]

2015 Expedition 38K
When I put the rear climate control (2)on heat and the electric setting the rear ceiling unit comes on. I assume it is a heat pump. What puzzles me is that the gas furnace also comes on. This doesn't seem right but...what do I know.

I understand that the front of the coach only operates in the heat position with gas using the front furnace.

[NLOVNIT]

Yes, the electric heat is via heat pumps.

In my Bounder, if the thermostat is set to more than 5 degrees from the ambient air temp, the gas furnace will kick in until that distance is closed. Once there, the gas shuts off & the heat pumps will maintain the set temperature.

I would assume your Expedition operates the same.

Lori-

P.S. The manual for the heating/ac system will explain this. If you purchased new, check the suitcase of manuals you rec'd. If you purchased used, hopefully the PO left that for you.

[mojoracing]

Ive never noticed that on mine. Then again if its that big a difference in temperature, I would usually kick both on to get up to temp faster. Ill have to check to see if that is how mine works.

[CLIFFTALL]

I believe that when you set the thermostat for heat , it will respond on both zones. If the ambient temp is within the heat pump range ( usually somewhere above 36-40 ) your rear heat pump will respond to supply heat to the rear and your gas furnace will respond to heat the front . If your temps are below the heat pump range , your gas furnace will heat both zones.

[pcurt23]

Originally Posted by kmx888

2015 Expedition 38K
When I put the rear climate control (2)on heat and the electric setting the rear ceiling unit comes on. I assume it is a heat pump. What puzzles me is that the gas furnace also comes on. This doesn't seem right but...what do I know.

I understand that the front of the coach only operates in the heat position with gas using the front furnace.

That is the way the system is designed to work. If the offset between the thermostat and the temperature in the coach is more than 4 degrees both the gas and electric heat will come on. If you are running the electric heat and the coach does not warm up the gas heat will come on.

If the outside temperature is 45 or more you can use the electric heat by increasing the thermostat 3 degrees at a time and then the gas will not come on. That is the way I do it. It is a PIA but better than using up the propane.

My electric heat will sometimes work under 45 degrees but not often. If it is above freezing you can use space heaters.

[chuckftboy]

I have 2 heat pumps and 2 furnaces so when it is above 38 degrees and I need to recover the inside more than 5 degrees, I simply turn off the LP tank and let the furnaces lock out to save propane.

[Brockx]

Lot's of good info above. Have only used my heat once and wondered about the gas unit coming on for a little while. One thought the front temp sensor is mounted on an outside wall and gets a completely false temp reading of actual "room" temp hot or cold. going to try to figure a way to move it.

[Gary RVRoamer]

I likewise have two heat pumps and two furnaces. If either zone is 5 or more degrees below the thermostat "set" temperature, the gas furnace in that zone will also kick on. Or I can select "furnace" on the t-stat and use gas furnace only, which is useful when it is too cold for the heat pump to function well.

The bottom line is that how it is "supposed to work" depends very much on the thermostat model and the associated zone controller, which is part of the heat pump unit.

[kmx888]

At what temperature do Heat pumps become "worthless"?

[NLOVNIT]

About 40-degrees. Although ours still put out heat, although minimal, down to about 35 but that's it.

Lori-