Truma Fault codes

[MikeS]

Hi folks, I wonder if anyone can help.
We’ve just arrived in Weybourne, Norfolk. We connected ehu, turned on the gas, bled through the gas, turned the gas hob on for a few minutes and checked the electric supply with a plug in tester. Everything was fine, 240v sockets working also 12v. Switched on the Truma 4e system and received an E746 H error code: “contact Truma”.
The van/Truma was new in 2019 and has been faultless since our first day with it. We’ve obviously had the occasional faults caused by switching the system on before connecting ehu or turning the gas on so we’re familiar with how to solve this.
We had drained down our water system at the boiler a few weeks ago and refilled and vented it before switching on. We last used our van 3-4 weeks ago and everything was fine.
We switched the Truma off for at least a couple of hours but still no joy.
Not the end of the world, we can boil water when need it but now showers for a few days!
Any suggestions?
Mike

 

[BouncyBoatFolk]

Perhaps not model specific, but it might be helpful.

Mike.

 

[Riverbankannie]

This is a chart of blink codes, the leds are under the cover on the boiler, might help identify the fault.

 

[Lenny HB]

I would try a reset on the CP Plus controller often solves error problems.

 

[irnbru]

I recall something about having to press the middle button for 15 seconds to reset the system. Have a google,

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[GeoffnDee]

Dont know if it is what is needed but there should be a boiler reset button under the wiring cover on the Combi , if the LED which is next to the button is red try holding the button down for 5 x seconds when it should turn yellow if it then resets.

 

[MikeS]

Hi folks, thank you so much to everyone who replied with all your helpful suggestions, everything is back up and running again. I tried all and the thing that finally worked was resetting the boiler/heater by removing the cover and pressing/holding the button next to the LEDs. I googled the fault code E746 H and couldn’t find any references. The red LED at the boiler was flashing the code: lslllslsls
I’ll call Truma in the morning to find out what the cause was and post anything Truma tell me. Thanks again it was really kind of you to take the time to help me out. What a great community. MikeS

 

[BouncyBoatFolk]

It doesn't take much for them to have a "hissy fit" even pulling the hook up cable when they are still on a heating cycle can send it into a paroxysm. Good it' sorted, well done, and thank you for updating the thread, it helps with possible cures for other people.
Regards.
Mike.

 

[MikeS]

Hi folks, called Truma today and it turns out that E746 H means that the 12v supply to the heater was too low, below 10.7v. Our vehicle was on EHU at home for 24 hours before we set off, the Hab batteries are in great condition so I’ve come to the conclusion that it must been an operator error. Having checked the gas and ehu were ok I must have turned heating on before checking that the 12v switch was also on. Does this make any sense? Geoffndee, your diagnosis was accurate. It proves that there is no escape from a detailed start up procedure once we arrive on site, I recall something similar from “Apollo 13”. Thanks again folks. MikeS