2015 Forester 3011 DS - Dometic A/C Heat Pump and Furnace Operation

[Ngeorgiacamper]

I would like to optimize the heat pump and furnace operation. My Dometic thermostat is the single zone with the Fan/Cool/Furnace/Heat Pump setting. I have used the rv 3 of 4 weekends October and November some with pretty chilly nights. When running on the furnace setting, my heat pump will run (I think it is on fan, as the air is cool) I thought to help circulate the furnace produced heat. More efficient?
First, is this typical of this combination setup?
Seconly, I saw at a camper show, many companies are goint to a digital based thermostat. Is this a good choice to change over to that technology. I can attest that the Trane digital in my home system is better than the old systems.
Thanks for any comments!

[Marnenorden]

On my Sunseeker, the fan must be set on auto for the furnace to work. If it's on low or high the heat pump runs and it won't heat beyond a low temp.

[Bama Rambler]

The Dometic single zone thermostat, uses their proprietary digital communication between the thermostat and A/C control box, so you can't easily or cheaply replace it with another brand.

[Kirk S]

Originally Posted by Ngeorgiacamper

I would like to optimize the heat pump and furnace operation. My Dometic thermostat is the single zone with the Fan/Cool/Furnace/Heat Pump setting. I have used the rv 3 of 4 weekends October and November some with pretty chilly nights. When running on the furnace setting, my heat pump will run (I think it is on fan, as the air is cool) I thought to help circulate the furnace produced heat. More efficient?
First, is this typical of this combination setup?
Seconly, I saw at a camper show, many companies are goint to a digital based thermostat. Is this a good choice to change over to that technology. I can attest that the Trane digital in my home system is better than the old systems.
Thanks for any comments!

Yes, by design your heat pump fan will run in furnace mode to help circulate the warm air if the fan is set on low or high. I don't like it and set mine on auto so it won't come on.

Please post a photo of your thermostat and hopefully someone with your type will be able to help.

Our 2017 Forester has a digital thermostat. Setting the fan mode to AUTO when using the furnace prevents the roof unit fan from running. If you are able to choose your fan mode with your current thermostat you might try that, if you haven't already, to disable the heat pump fan while using the furnace.

Another great feature we discovered is if the temperature drops too low for the heat pump, when the fan is set on auto, the mode automatically switches to furnace.

I'm attaching a photo of what we have. Maybe someone can tell you if it's an easy direct replacement or not as a two model year difference may have different control components. I am told there is a newer model that has bluetooth capabilities.

If you call Dometic with your heat pump model, serial number and thermostat info they may be able to help if you don't find it on the forum.
Good luck.

[Ngeorgiacamper]

Thanks for the reply. Sorry, I was not real clear. I didn't mean that I wanted to replace with a different brand thermostat. I would like to have the control to run the heatpump fans, the thermostat I currently have (attached), I don't think I can manually control the fan while running the furnace. While the HP fan runs with the furnace blowing, it can a little drafty if sleep under a open duct. I saw Dometic now has a digital with bluetooth which I think may give the control that I might want, I guess I need to see about compatability with the control board?

[ActionJackson]

All you have to do is put the Fan control on "auto", and it will not come on when you run the gas furnace.

[rlh1957]

A Heat Pump by itself will only give warmth when outside temps are about 45 degrees. Outside temps below that 45 degrees or if it's just not toasty enough most Heat Pumps in your house have an Aux Heat that kicks in whether gas or electric to supplement. I don't know if RV's have that Aux or Boost heat element in electric or gas or if they want you to use your furnace also. Atlanta is about as far north as Heat Pumps by themselves are effective and even then the Aux has to kick on to keep momma happy!

[Dcbenny]

Just came back from my trip where temps got down to 29* had thermostat set on heat pump and 70* and the heat pump keep MH comfortable where heat pump would cycle off when temps inside reached degree set. No time did furnace kick on.

[Marnenorden]

According to what I have learned about my Sunseeker, only the gas furnace feeds heat to the basement storage areas where there are plumbing pipes, etc.

[ActionJackson]

Originally Posted by Dcbenny

Just came back from my trip where temps got down to 29* had thermostat set on heat pump and 70* and the heat pump keep MH comfortable where heat pump would cycle off when temps inside reached degree set. No time did furnace kick on.

If control is set on"heat pump", gas furnace will not come on.

[Dcbenny]

Originally Posted by ActionJackson

If control is set on"heat pump", gas furnace will not come on.

If I have it set to HP and on auto if the HP cannot keep up mine automatically switches to furnace. Also read previous post by Kirk S

[Kirk S]

Originally Posted by ActionJackson

If control is set on"heat pump", gas furnace will not come on.

With my thermostat set on heat pump, the furnace will come on automatically when the Dometic heat pump cannot satisfy the thermostat. Evidently they don't all operate the same way.

[emm-dee]

Originally Posted by Kirk S

With my thermostat set on heat pump, the furnace will come on automatically when the Dometic heat pump cannot satisfy the thermostat. Evidently they don't all operate the same way.

Mine does the same thing. Very irritating when the heat pump is putting out sufficient hot air through the ceiling vents and keeping things nice and comfy, only to get blasted out by the heat from the furnace.

Anyone know how to prevent this?

[ActionJackson]

Originally Posted by Kirk S

With my thermostat set on heat pump, the furnace will come on automatically when the Dometic heat pump cannot satisfy the thermostat. Evidently they don't all operate the same way.

Hmm, I'll have to check that out. Do you have the same thermostat as pictured earlier?

Originally Posted by emm-dee

Mine does the same thing. Very irritating when the heat pump is putting out sufficient hot air through the ceiling vents and keeping things nice and comfy, only to get blasted out by the heat from the furnace.

Anyone know how to prevent this?

Couldn't you just turn the thermostat up some? The guy above said the gas furnace only comes on if the heat pump is not keeping up???

[emm-dee]

Originally Posted by ActionJackson

..............
Couldn't you just turn the thermostat up some? The guy above said the gas furnace only comes on if the heat pump is not keeping up???

May work..may not work. There doesn’t seem to be any set pattern to how the system works.

Sometimes I set the thermostat to 75 when the actual temp readout on the thermostat is 70. After a few minutes the furnace lights up. Another time I’ll set the thermostat at 76 with system displaying 69...and the furnace never comes on. The heat pump does a good job of warming the coach. Then, with no changes to anything, the actual temperature drops one degree and the furnace comes on.

I’ve been considering putting a switch in line to remove power from the furnace. Any thoughts from y’all about that?

[GL1800Rider]

Michael, if you are not needing the gas for anything maybe try shutting it off at the tank. Just a thought. Since yours is an Atwood it must be set up different.

We were camping in North Florida a couple of weeks ago and the temps got down to about 33. The furnace never came on and the heat pump kept us comfortable. It did go into defrost cycle a couple of times.

[emm-dee]

Originally Posted by GL1800Rider

Michael, if you are not needing the gas for anything maybe try shutting it off at the tank. Just a thought. Since yours is an Atwood it must be set up different.

We were camping in North Florida a couple of weeks ago and the temps got down to about 33. The furnace never came on and the heat pump kept us comfortable. It did go into defrost cycle a couple of times.

I still need gas on for the hot water heater (faster recovery than electric) and the oven/stove. Read in another thread about pulling the furnace 12V fuse. I'm gonna try that and if it works I'll come up with a way to re-wire the fuse through a switch. That may take a while.