Truma Combi E dead

[SeanF1]

Evening All,
I have a Sunlight T60 with a Truma Combi E Classic heater. The controls are the two knobs rather than the electronic panel. Before the big freeze I drained the water and boiler and left the auto frost valve open. Also left all the taps and shower open. Today I tried to put the heater on, on gas to warm the van up (without filling the water) but no led lights come on in the knobs and the heater isn't working. Batteries are full and all other 12v is working. Then tried it on 240 volts and it's the same ie not working either. It's as if its not getting any power. I have changed the 10a fuse for the heater in the EBL 119 but this made no difference. Anyone know if there is a way to re-set it?. I have tried getting access to the wiring panel on the back of the unit but it is in such a small cubby hole in the garage that I cant really get proper access to see. Any suggestions gratefully received. Many thanks, Sean

 

[TinaLes]

The only advice I can give is the obvious, check you have a 12V & 240V supply at the boiler itself, for which you will need a multi meter. It will not work on mains electric or gas if you do not have a 12V supply from the controller, are they any indicator lights on the control knobs? if not check supply fuse.
Sorry not familiar with the older type of Truma 6E without the display.
There will be a reset button on the side of the boiler, but I cant think of any reason why this could have been tripped by what you describe, but worth checking none the less.
Hope you find its something simple and can fix it.
LES

 

[JockandRita]

Hi Sean.

Not sure what model and age your Combi E is, but if you type in :Truma combi E reset." into a YouTube search, there are a few video tutorials available on the subject.

It sound like it doesn't have any power source at all.

Good luck sorting it out.

Jock.

 

[Lenny HB]

There is a 10 amp glass fuse on the boiler PCB for the 12v boiler power also a reset button on the PCB.

 

[GeoffnDee]

There is a fuse for the 12v operation under the wiring cover of the Combi boiler , (the boiler supplies the 12v to the controls) there is also a 230v fuse on the boiler and a reset button for 230v operation but they should not stop it working on 12v. It may be worth shutting the power down and then reconnecting to see if that resets things before trying to get at the fuse

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[TinaLes]

It looks like everything is pointing towards the fuse inside the boiler PCB, if that supplies the control panel.
I hope the Op has the room and dexterity to get at it, and find another glass fuse on flea bay, as glass fuses is something I know I don't have to hand these days.
LES

 

[SeanF1]

Hi Sean.

Not sure what model and age your Combi E is, but if you type in :Truma combi E reset." into a YouTube search, there are a few video tutorials available on the subject.

It sound like it doesn't have any power source at all.

Good luck sorting it out.

Jock.

Thanks Jock. It's a 2017 van so presumably a 2017 boiler. Problem is it's built into a tiny space under the bed, accessible only from the garage

 

[SeanF1]

It looks like everything is pointing towards the fuse inside the boiler PCB, if that supplies the control panel.
I hope the Op has the room and dexterity to get at it, and find another glass fuse on flea bay, as glass fuses is something I know I don't have to hand these days.
LES

Thanks Les. Is this the 12v fuse?

 

[SeanF1]

There is a fuse for the 12v operation under the wiring cover of the Combi boiler , (the boiler supplies the 12v to the controls) there is also a 230v fuse on the boiler and a reset button for 230v operation but they should not stop it working on 12v. It may be worth shutting the power down and then reconnecting to see if that resets things before trying to get at the fuse

Thanks GeoffnDee. I tried this but no joy I'm afraid.

 

[TinaLes]

Thanks Les. Is this the 12v fuse?

You will have to remove the PCB cover at the boiler to reveal the Fuse in its holder, I hope you can get an easy access to it
LES

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[GeoffnDee]

SeanF1 If you have a opening window over the heater exhaust outlet they can have a safety switch fitted that prevents the heater working (even when the window is on vent setting), I do not know if it turns off the controls but it may be worth checking if this switch is fitted on your Motorhome window (if there is one over the outlet)

 

[SeanF1]

SeanF1 If you have a opening window over the heater exhaust outlet they can have a safety switch fitted that prevents the heater working (even when the window is on vent setting), I do not know if it turns off the controls but it may be worth checking if this switch is fitted on your Motorhome window (if there is one over the outlet)

Thanks GeoffnDee. No window above

 

[Landy Andy]

If no lights on controls you need to know if you have 12v power to the boiler.

 

[SeanF1]

If no lights on controls you need to know if you have 12v power to the boiler.

Thanks everyone for your help so far.
I have taken the garage apart and gained access to the control panel. So far I have established that the unit DOES have 12v power coming to it and also that the 12v fuse is not blown (continuity shown by meter), but the unit is not coming on and there are no lights coming on on the control knobs. Any further suggestions very gratefully received. Merry Christmas all. Sean

 

[Landy Andy]

Next step to me would be see if you are getting anything at controls.

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[SeanF1]

Next step to me would be see if you are getting anything at controls.

Thanks Andy. How do I do that given that they are connected using ethernet type cables? Cheers Sean

 

[BouncyBoatFolk]

Did you disconnect, or turn off the Schault control box?
Mike.

 

[SeanF1]

Did you disconnect, or turn off the Schault control box?
Mike.

Thanks Mike. No everything is on and it's getting 12v in.

 

[BouncyBoatFolk]

Sounds like a reset needed. There's a great thread running currently on how to do this, with a video attached.
I have also added a photo to show [ if needed] where the reset button is.
My boiler is also located in the same place.
Mike.

 

[SeanF1]

Sounds like a reset needed. There's a great thread running currently on how to do this, with a video attached.
I have also added a photo to show [ if needed] where the reset button is.
My boiler is also located in the same place.
Mike.
View attachment 700014

Mine doesn't seem to have that button

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[BouncyBoatFolk]

Can you expose the board by removing the cover, [ it slides and lifts, from memory] then post a photo up, when you have the time. I don't heat mine, to no ill effects. It will have a reset button somewhere on the board. I note yours is the model before ours so slightly different in design, but probably not function. Have you the Truma manual that would have come with the van?
Mike.

 

[BouncyBoatFolk]

Not the specific fault you have, but does show how to reset an older style boiler if you're unable to find a reset button.
Mike.

 

[SeanF1]

Thanks Mike. Merry Christmas

 

[GeoffnDee]

If it is any help ,The 2018 onwards Combi PCB seems to be the one with the reset button shown. So a hard reset may work ,but there is normally a flashing led on the PCB indicating a reset is required and flashing a fault code. .
Have you checked the connections on the rear of the control knobs and also continuity of the ethernet type connection cable between the boiler and control knobs ?

 

[SeanF1]

If it is any help ,The 2018 onwards Combi PCB seems to be the one with the reset button shown. So a hard reset may work ,but there is normally a flashing led on the PCB indicating a reset is required and flashing a fault code. .
Have you checked the connections on the rear of the control knobs and also continuity of the ethernet type connection cable between the boiler and control knobs ?

Thank you. I have checked the connections but not the continuity. How is this checked with ethernet type cables.
?

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[GeoffnDee]

If you are able to get each end of the cable close enough for the leads to reach You could use a multi-meter (you may need assistance) , there is a you-tube video showing using a multi-meter to check an ethernet cable , or the data cables for Truma Combi are on e_bay and maybe a cheap short one (or a longer one) could be used as a temporary replacement to eliminate the fitted cable as the cause of the problem, they also sell extension data cables you could use to help with testing with a multi-meter.

 

[SeanF1]

If you are able to get each end of the cable close enough for the leads to reach You could use a multi-meter (you may need assistance) , there is a you-tube video showing using a multi-meter to check an ethernet cable , or the data cables for Truma Combi are on e_bay and maybe a cheap short one (or a longer one) could be used as a temporary replacement to eliminate the fitted cable as the cause of the problem, they also sell extension cables you could use to help with testing with a multi-meter.

Many thanks

 

[SeanF1]

To follow up on this issue, in case anyone has any further suggestions; Truma Combi 6E not coming on, either on gas or 240v and no lights showing on the analogue control knobs. I have established the following:
1. The truma unit is getting 12v supply
2. the 12v fuse is good as I'm getting continuity through it
3. There are no LEDs lit or flashing on the pcb
4. there are no lights coming on on the control knobs
5. There is good continuity on all the pins in the RJ12 connectors from unit to control knob and between the two knobs.
Is it likely that the main control knob has failed. is this a known thing and is there a way of testing this?
Could it be a faulty room temperature sensor and is there a way to test /override this?

I have noticed that when I plug in the EHU to the van, the truma unit "ticks" for about 30 seconds, and ticks again when I disconnect the EHU but nothing else happens.

Thanks in advance for any further suggestions. I have tried to call Truma customer support but they are closed until 3rd January

 

[Lenny HB]

Could it be a faulty room temperature sensor and is there a way to test /override this?

I very much doubt it will be that but if you disconnect it the boiler will run at full pelt if it's working.

 

[BouncyBoatFolk]

Dry joint on the mother board somewhere ??
Mike

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