E1 message and thermostat

Helipilot · 09-09-2018, 11:41 PM

After a 700 mile trip I got the E1 message (lost commo between thermostat and the A/C units)

My question is does the Dometic thermostat cover just pop off or is there some magic trick to remove it to start checking the connections in the closet before I climb on the roof?

The unit is a 2011 DRV Mobile Suites 36 RSSB3 with vanity slide. Great unit and trouble free. Just installed the Samsung residential refrigerator with a 2000 watt Magnum inverter, and my sweet wife of 50 years loves it.

Answers appreciated and I will check with the factory tomorrow as well. Interesting how things happen on Friday evening.

Notanlines · 09-10-2018, 05:45 AM

What might I ask is "commo?"

**wingnut60** · 09-10-2018, 07:33 PM

Communications.
I don't have any advice on this, never had a problem.

Helipilot · 09-11-2018, 12:45 AM

Well, thanks for looking folks. "Commo" is aviation slang for communications between two or more parties.

The factory had me on hold so long I hung up. Perhaps Monday is a busy day with everyone out camping or whatever. It is not an emergency as I am back at home base.

**wingnut60** · 09-12-2018, 08:05 AM

When you say 'factory' do you mean DRV or Dometic? I would trust Dometic more on this issue.

Helipilot · 09-12-2018, 11:55 PM

Good point wingnut60. I will call Dometic in the AM. Thanks for the thought!

Helipilot · 09-14-2018, 11:26 PM

Update: The A/C system communicated via a reverse polarity telephone type wire. It runs from the thermostat to one of the a/c units on the roof and those two units are connected by the same type of wire to each other. If a fault occurs in any of those two wires the E1 code occurs and both units shut down.

Once I understood how the system worked I was able to "pop" off the cover on the thermostat and run continuity tests throughout the system. The wires were all OK. The issue was the "mother" board on the rear heat pump/air conditioner. I have one inbound and that should solve the problem.

I guess my 50+ years of commercial flying and rebuilding aircraft paid off as I had the test equipment to track down the problem.

Helipilot · 09-22-2018, 12:20 AM

Well, good news...the mother board was not the problem so I saved a bunch of money on that. The thermostat has failed for some unknown reason, a new one is inbound Monday 9-24. Will report on the progress at that time.

Jim Keefer · 09-22-2018, 03:03 PM

Can anyone tell me how to reset the Dometic thermostat? My little mind seems to forget when I really need it!
Thanks folks!

Helipilot · 09-22-2018, 11:55 PM

What thermostat do you have Jim? I have the Dometic with 9 buttons, if I remember correctly. Since my was not working properly anything I might say at this point could be wrong. I will reply to this thread on Monday after the new one is installed.

Jim Keefer · 09-23-2018, 07:46 AM

Mine is the older 5 button “Comfort Control” with on/off at bottom right! It is the original in my 2005 CK3 Mobile Suite!

Helipilot · 10-24-2018, 11:03 PM

Update...after working two full days with a tech we discovered the issue was the front A/C unit. The motor was in the process of failing and was causing a major power draw on the system and kicking out the circuit. Waiting on a new motor.