Truma CP Error W255H

[dkeen]

I just picked up my new LEII on Tuesday and stayed at Oliver for 2 nights to test everything out.  Had no issues and headed back home to western NC.

It was cool in the mountains this morning.  I realized that I did not try the heater while at Oliver as it was in the 90's so I tried to turn on the heat. On the truma control panel, I hit the camper symbol and turned the dial to heat and set to 80 degrees and pressed the dial to confirm.  The fire symbol showed up above the line but no heat and no fan.  The hot water heater was working fine.

After researching I found the warning triangle on the screen and pressed it and code W255H came up.  In the manual it show this as a warning that the control panel is not communicating with the heater.  I turned everything off then turned the control panel off.  Then turned the Xantrex off (was running on battery.  Turned Xantrex back on then Truma CP back on.  Tried again and got the same error.  I hooked to shore power and tried again, still nothing.

Read the manual more and then decided to reset the Truma CP.  Probably not a good idea.  Now I have no symbols on the CP for heat or hot water, only AC and Fan which both work.  I posted on facebook and here to see if anyone had any suggestions.  Then I called Oliver and did not realize that they close at 11am on Fridays.  Hopefully someone here or on Facebook will have a simple fix for me, if not I will reach out to Oliver after the holiday weekend.

Happy Memorial Day and please remember all of those who gave us the ultimate sacrifice.

[Galway Girl]

For truma communications between devices on the inside controls they use a data cable with network or phone style connections.  There should be one plugged into the right side of the water heater looking from the outside above the power switches and behind the larger white cable connector. If it’s plugged in then check the other end at the control panel. 

 

 

 

 

 

[Snackchaser]

Disclaimer - I have zero knowledge of these units, I 'm just going on basic trouble shooting methods.  

If you did a factory reset on the CP, then it probably needs to be re-paired with the devices (furnace, Water Heater, and AC ... assuming that the AC is also a Truma).  

Start by going into the CP setup/pairing mode to see what devices are connected and/or available for pairing.  It could be that the furnace was never paired during initial setup.  The manual should have instructions for this.

If the Furnace is not listed, then check the furnace fuse because it needs to have power to talk to the CP.  Next check the LIN cable as @Galway Girl showed in the video, only it's the one for the furnace not the water heater because you said the water heater was working fine.   Look closely at the pins on the LIN cable, they could be bent and not making proper connection.  If the furnace end is fine, then check the CP end.    Last but least likely, the furnace board might have issues.  

This is a good start, but there could be other problems to.  Hopefully someone with more familiarity will chime in. 

Good luck and let us know what you find