Dometic CoolCat furnace not blowing warm air

NewTabby19

Hi all,

I have a 2019 Tab 400 Boondock that I bought last fall. I only took it out a couple of times before winterizing. We used the Alde heater just fine but never tried the Dometic. Temps were in the 50s yesterday and I decided to go out and try it out. I’d just picked it up from the dealer where I had asked them to order a couple of unrelated parts, replace the roof seals and check that the AC is blowing cold. They said it was fine. The trailer was plugged into shore power and the Alde was off. I turned on the Dometic thermostat and set it to heat mode, high fan, 75 degrees. After running for 15-20 minutes, it was still blowing cool air. Any suggestions on how to start troubleshooting this? I wasn’t happy with the service from the dealership and don’t want to take it back in if I don’t have to. 

Thanks!

Denny16

Is the trailer connected to at least 20-amp shore power service?  The thermostat for the CoolCat needs to be set higher than the temperature in the trailer, any direct sun shinning on the thermostat could prevent the heat from coming on.  Try resetting the control panel, to heat, fan on auto and thermostat set above the measured cabin temperature (you can use the Alde panel to see the cabin temperature by the door.  You could also try leaving the door open if it is cool outside.

My initial test of the CoolCat in heat mode didn’t work either.  The second try I did what I suggested above, and it worked.  It takes a few minutes to get the heat coming out.  Also make sure to remove the cover on the outside vent.
cheers

Sharon_is_SAM

I thought I read that nuCamp had at one point installed a CoolCat for A/C only.  When did that occur?  Was that the current 2021 model?

Denny16

Sharon, Our 2018 has the CoolCat heat pump.  Basically, the CoolCat compressoe is reversed the coolant direction is reversed for generating heat into the cabin, and cold air is discharged out the vent.  This is how a heat pump type AC/heater works.  The heat is not instant, like getting thenAC to blow cold air, it takes around 3-5 minutes to get the heat going.  There have been several discussions here, about this feature on the TaB400.

Dutch061

Denny16 said:

Sharon, Our 2018 has the CoolCat heat pump.  Basically, the CoolCat compressor is reversed for generating heat into the cabin, and cold air is discharged out the vent.  This is how a heat pump type AC/heater works.  The heat is not instant, like getting thenAC to blow cold air, it takes around 3-5 minutes to get the heat going.  There have been several discussions here, about this feature on the TaB400.

Actually there is a switching valve that reverses the flow direction of the refrigerant. This swaps the function of the evaporator and condenser to allow it to remove the heat from outside and move it inside. When in AC, it removes the heat from the inside and moves it outside. 

Brad

N7SHG_Ham

The "heat" function is not enabled on the CoolCat in the Tabs, the heat pump function does work and will output warm, not hot air (depending on outside temps and ONLY if above freezing). It takes a few minutes, but works well in moderate outside temps to get morning chill off.

Denny16

OK, thanks Dutch061 for the clarification on how the heat pump works (edited my post).  Whilst the heat function may not be fully enabled, it does work to warm up the YaB400 quite nicely when the cabin is at 40-55F.  I have used it for just that, got the TaB400 cabin from 45F to a nice 70F.
cheers

bergger

Make sure you did not have the thermostat on "furnace" mode, as mentioned by N7SHG_Ham this function is not operational as there is no furnace connected to the thermostat.  This would be used if there was forced air furnace in the trailer.  Make sure you cycle through the thermostat functions and select "heat pump."  Give it a few minutes and it should work.  If not then something is not working correctly with your unit.   

Denny16

Good point Berger, the CoolCat heat function has two settings, this is what tripped me up the first time I tried using it for heat.  You need to press the heat function button a second time to get the heat pump function activated.  Use a torch (flashlight) to see the Cool Cat display more clearly.
cheers

NewTabby19

This is great information, everyone. I think I may have had it on the first heating option and not the second heat pump setting. Also, I have power running to the trailer from a regular outlet in the garage. I’ll check the amps on that breaker and see if that might be part of the issue. I will give these troubleshooting tips a try and let you know how it goes. Thank you!

NewTabby19

@Denny16 - that was it! I didn’t realize there were two heat settings. I had it on furnace, not heat pump, that first time. I switched the fan to auto and set it to heat pump and it warmed right up. Thank you!

Denny16

You are welcome.  This two part heat setting got me the first time also.
cheers

Snoblett

Is the “Furnace” function not operational for the 2021 Tabs , too?
I have the Dometic model # 441003.701 / 441003A.701

Also, and out of curiosity, is it stated anywhere in the NuCamp user manual that the Furnace function of the Dometic is not operational and to be ignored, or is this Tribal Knowledge that has been passed down via the forum.

thanks all 

N7SHG_Ham

AFAIK, none of the CoolCat systems have an active furnace function (heat strip), they only have AC and heat pump functions.

Sharon_is_SAM

@Snoblett - the 2021 400 Owners Manual does not address the absence of the “Furnace” function of the Dometic CoolCat.
Only the “Heat Pump” setting delivers warm air.  This was discovered and shared by forum members.  NuCamp may rely on dealers to share that info.

Snoblett

I had combed through the user manual, but didn’t see it, but I have been known to miss things reading, so I figured I’d ask the forum.

Thank goodness for the forum!   ☺️