E1 Error on Thermostat

[Catluver67]

Well I’m circling back. I have read through as many E1 error threads as I can find and no luck so far.

I have 3 zones…2 & 3 had E1 errors…both have disappeared totally after doing the domestic reset of holding down Zone and Mode to initialize. Zone 1 shows and will intermittently work. I ordered a power control board and swapped it out with 2 and then 1 to see if that would help but it did not. It’s all still the same. I also use a Micro Air thermostat…no change on it either. It shows zones 1 and 2 and 1 was working but now it’s not…now shows communication error. Just have no idea where to look and not enthused about taking it down somewhere. My understanding is the thermostat runs to Zone 1 then to 2 then to 3…that’s why I thought the issue was probably the Zone 2 board but it wasn’t or I’m not doing a hard reset or something???

Anyone have any ideas? I’ll call Dometic next…last time I called they were not any help and just wanted part numbers etc.

[Skip426]

Do you know the thermostat part number ?

Does it look like one of these pictures ?
Or like the second photo only with five buttons?

EDIT : Loss of zones , is usually a result of wiring communication issues between the secondary zones and the main ( front A/C ) .

[Catluver67]

Yes…it’s the 10 button top one.

E1 error is:
E1 Loss of communication between the CCC 2 thermostat and an individual system power module board. The LED will display error code EI and the zone number that lost communication. Any additional zones that loose communication will blink in addition to the current zone.

Just not sure where to troubleshoot. Since it wasn’t 1 or 2 PCB.

[Skip426]

I can't say if the zone two roof unit shares a common cable with the zone three; or if zone three has a communication cable direct to the zone one roof unit .
I would suspect since both zones dropped out at the same time that the cable runs from 3 to 2 then to 1 . So the issue could be the communication cable in zone one ( connection to that control board ) the cable between 1&2 , connection at zone 2 control board ( or the board it's self ).

I'm thinking that diagnosing your issue will mean time on the roof with a known good cable , to connect zone 2 board to zone one control boards.

There is a pdf file in the " Files" drop box ( DuoTherm CCC ) that covers communication issues between two roof top units on older coaches that could have useful info.

EDIT: I'll see if I can track down the site's RV systems guru , and link him to your thread .

[inthepines]

if this is the tstat I'm thinking of, is there an app they show you can download to your phone?
If so you have to install the app or else you will get a loss of comms and need to reset the tstat every 48 hrs basically.
If this just started than ignore me. Just made me think of one I was working on a while back.

[Catluver67]

Originally Posted by inthepines

if this is the tstat I'm thinking of, is there an app they show you can download to your phone?
If so you have to install the app or else you will get a loss of comms and need to reset the tstat every 48 hrs basically.
If this just started than ignore me. Just made me think of one I was working on a while back.

I do have an app for the microair tstat. It has worked great for about a year…I mostly use the app to talk to it.

[Catluver67]

Originally Posted by Skip426

There is a pdf file in the " Files" drop box ( DuoTherm CCC ) that covers communication issues between two roof top units on older coaches that could have useful info.

Thank you I will look for that file.

[Old-Biscuit]

Error E1 was originally showing for zones 2 & 3 but after rest that error for 2 & 3 cleared
E1 and zone 1...........intermittent function

Suspect Zone 1 board/connections are where issue lies
Could be cable connection


When you did the reset (mode & zone held down) did the display show “IniT” and all available zones. (1, 2 & 3)??

[Catluver67]

Originally Posted by Old-Biscuit

Error E1 was originally showing for zones 2 & 3 but after rest that error for 2 & 3 cleared
E1 and zone 1...........intermittent function

Suspect Zone 1 board/connections are where issue lies
Could be cable connection


When you did the reset (mode & zone held down) did the display show “IniT” and all available zones. (1, 2 & 3)??

That’s all correct…when I did the IniT zone comes up but NO zones show up at all there. Once I exit out of that then 1 will show up like it sees it and will sometimes work and sometimes it says communication error.

[Catluver67]

Resolution update in case it helps anyone down the road.

Looked at the wiring diagram I got off Newgle and it showed Thermostat going to zone 1 and then 3…not 1-2-3 like newmar told me a couple of times. Changed out the power control board on 3 and all show up and work! I attached the wiring diagram and highlighted it in red.

[Old-Biscuit]

Who would have though!

Thanks for update and resolution

[Skip426]

Originally Posted by Catluver67

Resolution update in case it helps anyone down the road.

Looked at the wiring diagram I got off Newgle and it showed Thermostat going to zone 1 and then 3…not 1-2-3 like newmar told me a couple of times. Changed out the power control board on 3 and all show up and work! I attached the wiring diagram and highlighted it in red.

Just a little confused here .

I'm thinking ; that just maybe ; the RV was available with just 2 roof air units ( as the diagram you posted doesn't show a central roof unit or the wiring connection ), so they would be ; front /zone one , rear/zone two .
When the third roof unit was added , it took on the zone two designation and the rear became zone three. BUT instead of re-doing the wiring to 1-2-3 .
They connected the central unit to the rear and left the wire from the rear unit to the front in place , so the control wiring sequence is now ( 1-3-2 ) .
Just a thought ; but it would have been nice not for you to have to figure it out for yourself.

EDIT: After downloading and blowing up the diagram , I see the central roof A/C unit ; BUT ; no wiring to either the front or rear .