Dometic A/C Thermostat Replacement Problems

[tredavon2100]

I have a 1999 Newmar Dutch Star. It originally came with 2 Penguin rooftop A/C's with Heat Pump, Model 630215321. They were originally controlled by one Dometic Duo-Therm 4-Button Thermostat.

Both units stopped working. The previous owner replaced the front unit with a Dometic A/C with Heat Pump, Model 651816CXX1C0. The rear unit was disabled. The original 4-button thermostat was replaced with a 5-button Dometic Duo-Therm thermostat known as Comfort Control Center (Dometic part #3109228.001) and the required Dometic Comfort Control Center Upgrade Kit (Dometic part #3310009.000) was installed in the new front unit. The front unit controls everything. Only the "Zone 1" dip switch is set to "on".

Problem: The new 5-button thermostat does not show "Heat Pump" as a mode to select. It does show "furnace". I would prefer to use the heat pump function to save from using propane for the gas furnace.

So..... I called Dometic and was told that the new front A/C Heat Pump unit requires the 12-button Dometic Duo-Therm Thermostat known as the Comfort Control Center 2. They said that should allow the "heat pump" mode to show up. I ordered that item from Amazon.com and was sent a Dometic Comfort Control Center 2 Thermostat (part #3314080.015). I performed a system reset.

New Problem: Now, no zones show up at all. I performed a system reset 2 times.

Any ideas?

[RV Wizard]

They failed to inform you that you will need control board(s) for the roof unit(s).

[TQ60]

Too many variables.

Go back 3 spaces...

If front unit was replaced and was working as ac but not heat pump then if it was a heat pump unit then there may be a dip switch setting on control board.

We replaced our 22 year old ones with a pair of 7 year old heat pumps that used the 5 button control and me thinks there was a dip switch setting on control for zone, heat pump and maybe unit number.

You set switch then do a reset on thermostat.

Why is other unit offline? Wrong control?

Get the full model number then get a soft copy of the manual.

Turn off the ac breakers then get on the roof and open the cover then open the metal box on the right side containing the control board.

Write down the part number if you can find it and get some photos too.

Look for a dip switch to set options then note how they ate set then set per what you need if correct.

Me thinks the PO installed new ac with correct thermostat for that unit but installer did not set it properly.

New unit not compatible with second unit so it was left off.it may be compatible but that is another task.

[chboone]

I have the manual for setting the dip switches for various AC systems including heat pumps. Send me a PM with your email address and I will email it to you. Can't unload it here because it is over 3 MB. My control boxes with circuit boards with the dip switches are inside the MH mounted in the AC return air above the filter.

[tredavon2100]

Thanks everyone!! Your information was very useful.

TQ60 - you are right - too many variables!
RV Wizard - unfortunately, the installer didn't use the control board that came with the new unit.
CHBoone - I will try to figure out how to message you with my email.

It seems that the installer did not use the board that was included in the box with the new unit. They kept the old control board in since it did work with the new unit and the existing 5-button thermostat - just no heat pump selection.

More than likely, they did that because the owner was planning on selling the motorhome and didn't want to buy a new thermostat to go with the control board that came with the new unit.

The installer also did not have the dip switches set properly.

Here is our plan going forward:

Since we DO need a new rear unit, it would be best to continue using the 5-button thermostat until we get the new rear unit (even though it we can't get the “Heat Pump” selection).

We will keep the new 10-button thermostat we just ordered from RVPartsCounty.com (Dometic Comfort Control Center 2 - Dometic part #3314080.015) for when we get a new rear unit.

We will soon buy a new rear A/C Heat Pump unit.

We will then install the new 10-button thermostat and order the correct Comfort Control Center 2 - which goes with it.

Thanks, again!!

[chboone]

Click on my name, select send private message from the drop down menu. The manual I have is for the 5 bottom control.