Help with Thermostat COMM wiring

JimboTJ

Member
Hey all. I have a single zone Dometic thermostat that is flashing E1 when trying to run the heater. I know this is a wiring or communications issue between the thermostat and the furnace, but I have no idea where the COMM wire runs to. I assume it runs to a board that controls the AC and furnace, but I have no idea where to access that. Any help would be much appreciated!

Thanks in advance!
 

danemayer

Well-known member
Hi Jimbo,

On many units, the control box is in the ceiling with the AC return, just above the filter.


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jimtoo

Moderator
Hi JimboTJ,

Welcome to the Heartland Owners Forum. We have a great bunch of folks here with lots of information and all willing to share their knowledge when needed.

If you would tell us what unit you have and model it might help. Maybe someone with the same thing has had the problems and can direct you to the correct area.

Enjoy the forum.

Jim M
 

jbeletti

Well-known member
Control box may be outside on the AC, under the cover. I know once I got a unit and there was no furnace selection on the thermostat menu. Turns out the configuration (DIP switches) was off. A quick reconfiguration at this box and it was good to go. I'm guessing that the cabling led up to this area.
 
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