Dometic CCC2 E1 Error - No Furnace Control

asrtaylor

Member
I finally was able to open up our 2012 Mesa last weekend and ran into a Dometic CCC2 issue. The main Dometic CCC controller for the kitchen / living room had an E1 error and only shows Cooling, Fan and Off, where the CCC in the bedroom shows Cooling, Furnace, Fan, and off (and no E1 error).

I tried unplugging the comm cable on the main CCC thermostat, which got rid of the E1 error, but the furnace still is not showing up. I did an init of the main CCC thermostat and now Zone 1 is flashing and Zone 4 (never had a Zone 4 before) is solid, but still no furnace option. Hence, no heat in the trailer as it seems the main CCC must be working before the bedroom CCC will kick in the heater.

I still have to try moving the CCC from the bedroom to where the main one is and vice versa and see if the furnace shows up on that one Hesitate to do so if I have to init that thermostat from the bedroom one (it does turn on the AC unit in the bedroom when I tested, but not the furnace, hope that make sense).

I hope my comm cable hasn't gone bad, that looks like a pain to re-route?

Any other hints or trouble shooting ideas I can try this weekend? I downloaded the diagnostics instructions as well, and have to try them (Program, Fan, F/C button at same time).

Note: the instructions on doing an init from Dometic says turn the thermostat off to do the init. Maybe wording, but in the CCC is 'off', it won't init. I turned the CCC on (but nothing operating) and it showed init, until I pressed the power button again. Am I missing something?
 

danemayer

Moderator
Staff member
Only one thermostat is connected to the furnace. You might have a heat function on the other if it's a heat pump unit or if it has heat tape. But the main, propane-fired furnace is only connected and operated by one thermostat.

On older Landmarks, the bedroom A/C unit is not ducted - it blows air out of the louvers in the A/C unit. That unit is connected to a thermostat that most likely does not operate the furnace.

On those older units, the main living area thermostat connects to a control box in the ceiling, above the A/C air return. That could be where the E1 communications error needs to be investigated, along with the connections at the thermostat.

On newer units, the bedroom A/C is ducted into the same ductwork as the living area A/C. On those, the thermostat for the living area probably connects to the rooftop unit. For sure an E1 error can be caused by a corroded connection up there. A spritz of DeOxit will often clear that up.
 

asrtaylor

Member
Only one thermostat is connected to the furnace. You might have a heat function on the other if it's a heat pump unit or if it has heat tape. But the main, propane-fired furnace is only connected and operated by one thermostat.

On older Landmarks, the bedroom A/C unit is not ducted - it blows air out of the louvers in the A/C unit. That unit is connected to a thermostat that most likely does not operate the furnace.

On those older units, the main living area thermostat connects to a control box in the ceiling, above the A/C air return. That could be where the E1 communications error needs to be investigated, along with the connections at the thermostat.

On newer units, the bedroom A/C is ducted into the same ductwork as the living area A/C. On those, the thermostat for the living area probably connects to the rooftop unit. For sure an E1 error can be caused by a corroded connection up there. A spritz of DeOxit will often clear that up.


Thanks for the reply so fast. Learned something new. Will pop onto the roof and see if I can find the comm cable at the AC unit (my AC is ducted returns if I'm understanding you, I don't have the large square area that I had in my old unit, that had the air return and filter in it).
 

TravelTiger

Founding Texas-West Chapter Leaders-Retired
Just a quick thought and I’m no expert, are you plugged in to power? Is your battery fully charged? A low battery is known to cause issues with the furnace.


Sent from my iPhone using Tapatalk
 

asrtaylor

Member
Just a quick thought and I’m no expert, are you plugged in to power? Is your battery fully charged? A low battery is known to cause issues with the furnace.


Sent from my iPhone using Tapatalk


Thank you for the reply. Yes, I'm, on 50Amp shore power with 2 full charged batteries.
 
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