Dometic CCC2 Thermostat "E1" Error Code Repeating

[cstar5634]

The subject thermostat in my 2015 Ventana (all electric) keeps going into "E1" Communications error code in both heat pump and hydronic heat modes. Took the coach to Independence RV in Orlando who found phone type connections on roof A/C units were clogged with wood and Styrofoam chunks so they replaced these connections. Heat pumps worked for a few days (we're currently in Southern Florida), but woke up this morning with E1 code again. This has been an intermittent problem since we've owned the coach but failures are now much more frequent. Considering whether to take it back to Independence or back to the factory to try to get this resolved once and for all.

Writing this to see if there are others in this forum community that might have dealt with this same issue and what their ultimate solution was.

Thanks for everyones input.

[shaman52]

Replacing the RJ11 com cable ends was a good attempt by Independence RV at curing the problem.


Since that failed to repair you are looking at replacing your com cable from #1 a/c (front) to CC2 thermostat. Last year I replace all three Dometic Heat Pumps and had to run a new com line between #2 and # 3 Penguin II's due to a one open wire.

Try running a temporary RJ11 cable from CC2, out the window/door to #1 A/C. If this works you know absolutely it is that run. Other thing you need to know is that the pin out of the com cable is not just telephone cable it is special to com cable. See page 9 of attached PDF for your CC2 thermostat.

You can buy the loose RJ 11 ends and the crimping tool at Home Depot. Run the com cable all the way to your roof top control board. Do not use the short com cable connector at A/C. It has reverse pin out that corrects the normal Newmar installed telephone run. If you do not want to make your own com cable you can run telephone RJ11 cable to the short connector to you # 1 A/c control board. It is harder to put in words just than show you but it is all I have to communicate with you.


Here is the $79 Klein VDV Scout Pro 2 Tester Kit
testing tool. Bought at Home Depot. Found that found the open wire. It shows pin out too.






Crimper:



Good Luck!

[ghaynes754]

I bought the Klein tester so that I had a faster way to check Ethernet and coax cables. Great tool that is easy to use and will find any issues with your wiring.