Can anyone help to explain this mystery?

RichardandKaren

RichardandKaren

Free Member
Joined
Oct 4, 2017
Posts
149
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Location
Leamington Spa
Funster No
50,836
MH
Rapido 786F
So, recently my Truma ( older C6002) has been playing up. More often than not ( but not always), when it's on my drive at home and when I put the heating on it locks out and the red light comes on the control dial. This is whether it's on hook up or on leisure battery. However, if I take the van even for a short 10 minutes drive then when I get home the heating comes on first time ( on ehu or leisure battery) and works perfectly! Then a day or two later the same problem reappears and, again, a short drive sorts it out! My own conclusion is that this is some sort of loose electrical connection maybe but, if that was the case, why would it not work a day or two later when it has been standing still on my drive? Also, thought about could this be a problem with the gas solenoid getting bunged up and a drive somehow clears it a bit? By the way the hobs/oven/fridge all work perfectly normally on gas and the gas cylinder is about 3/4 full. Any suggestions?
 
is your battery charged and the charger working correctly as sounds like the drive is charging the leisure battery so it all works OK?
 
If it only happened on battery I would say low voltage and a quick run is just putting enough in for it to run.....then the surface charge is dropping over a day or two
Are you sure the mains charger is ON and charging the battery....if it's off or maybe tripped the above may apply
 
Hi, I did consider voltage issues, but wouldn't that be precluded by the fact that the same problem happens even when it's on hook up on my drive? Also, I have a voltmeter thingy plugged in to one of my hab 12v sockets in the van and it clearly shows leisure battery at 13.1v when not on hook up. It goes up to about 14.2v when on hook up. When I plug same thingy in to the cig lighter in the cab ( which is only connected to vehicle battery) then when ignition is on it shows vehicle battery at 12.7v. So, I assume that battery charger etc is all working fine.
 
It certainly sounds like it's charging.
I'm at a loss unless it's a fault on the control board

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I was wondering about the control board. I think there is a place that charges £50 to test them and will repair if they find a fault. Maybe I should just take it out ( is it easy to do?) and send/take to them. Cannot remember the name of the place but think they have been mentioned on this site before.
 
Found this link for Truma,(see below) apologies if you have already looked also, but maybe give them a call, their service team may be able to suggest where to look first, as you may remove the control panel get it serviced only to find there is a problem somewhere else like the boiler control board, or loose connection.
Good luck.
LES
www.truma.com

Truma Combi heater • Operating instructions and help!

Technical specifications: operating instructions and info on gas consumption of the Truma Combi heater. PLUS: What to do when you have problems with Combi 6 and Combi 4, etc.?
www.truma.com www.truma.com
 
Thanks Les. I did speak to Truma in Derby who are generally quite helpful. They said it sounds like a mystery and could be any number of things! The only thing they can do is for me to have the whole boiler taken out of the van then take it/or ship it to them and they will test it ( presumably for a charge) then and if ( and they stressed it's a big IF) they have any spare parts they could fix it. All of that doesn't sounds like a great option to me. I have now found the company that advertises a £50 fault finding service on the PCB Board for a C6002 - it's A&R Electronic Developments in Cannock. Think I may go down that route first. If that doesn't sort it then I have a got a local mobile guy who has been good and he suggests he takes the boiler out then strip it down at his own workshop and see if he can find anything wrong/repairable. He reckons about 5 or 6 hours work @ £55 per hour. All very frustrating as when it does fire up it works absolutely perfectly! Obviously, what I am desperately trying to avoid is having to fork out about £2K to fit a brand new Truma Combi 4E to the van. Frankly, think I'd rather sell the van at a discount against the going price and be upfront to any buyer about the intermittent issues with the boiler.
 
Are you using propane or butane, and how much gas is in your bottle ? Shaking a nearly empty gas bottle (like taking it for a drive) will sometimes give you a bit of extra pressure that might just be enough to fire up your Truma ?
 
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Propane and "magic eye" ( which I know is about as useless as a chocolate teapot) suggests about 3/4 full. But your suggestion is a good shout - I will go out side and changeover to what I know is a full Calor Gas cylinder and see if that makes any difference.

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Red light normally means low voltage but it doesn't appear to be the case.
The C6002 did have a bit of a reputation for connection problems on the looms to the PCB. I had one that kept playing up, I unplugged all the connectors sprayed them with contact cleaner, pushed then on & off a few times, it never went wrong again.
 
I'm dubious about the loose connection or pcb fault theory as it seems a bit of a coincidence that it starts and runs fine after driving unless the hab battery voltage is low and the onboard charger isn't charging it.
Since it seems that a bit of jolting has it working until it has been stood unused for a while I'm wondering (clutching at straws actually) if there's a recurring blockage in the boiler inlet/outlet air vent e.g. flaky dirt/rust? a leaf? spider web? mouse? which clears with a bit of jolting or wind rush then re-obstructs the flue after being left standing unused. (Stranger things have happened ;) ).
 
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Hi Spriddler - I have recently taken flue outlet off and ensured it’s all clean and I’ve also put on a new outlet hose so I don’t think this is the problem.
 
I am no expert but it sounds like the gas control valve is sticking. Lack of use makes them stick. I tapped mine with a hammer ( gently) and it cleared the problem

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We have recently had problems with the central heating from our Truma boiler. We took it to be overhauled by Truma in Derby (done whilst we waited) and it was well worth having done, given your location you might want to consider doing the same.
 
On yours a flashing red light denotes low voltage a fixed red light is normally a gas problem. Can you her the combustion fan running when you first start up. If you get someone to turn it on whilst you listen at the outside vent. If the combustion fan does not run it will lock out. Possibly when you drive the bumping loosens the fan hence it will run but when left stationary for a bit it sticks
 
Bessy765 said:
On yours a flashing red light denotes low voltage a fixed red light is normally a gas problem. Can you her the combustion fan running when you first start up. If you get someone to turn it on whilst you listen at the outside vent. If the combustion fan does not run it will lock out. Possibly when you drive the bumping loosens the fan hence it will run but when left stationary for a bit it sticks
Click to expand...
This was the exact issue with ours... Peak Caravans came and sorted it by fitting a fan and it's been ok since, although ours is a Truma Combi.
 
jockaneezer said:
Are you using propane or butane, and how much gas is in your bottle ? Shaking a nearly empty gas bottle (like taking it for a drive) will sometimes give you a bit of extra pressure that might just be enough to fire up your Truma ?
Click to expand...
I had a similar prob when bottle was 1/2 full changed regulator and all OK now
 
Had the same problem some years ago when the red light would come on and had to reset the boiler. Found out by an excellent engineer (now retired) that the thermostat needed changing and it solved the problem.

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Mr Librium said:
This was the exact issue with ours... Peak Caravans came and sorted it by fitting a fan and it's been ok since, although ours is a Truma Combi.
Click to expand...
One other thing you might TRY, as you appear to have not done so far, is running your engine and THEN try starting it. The running alternator might just give that extra power needed on start-up when max is usually needed. 12.7 is not, nearly but not, fully charged. ( Yes the EHU SHOULD do the same but....., what have you got to lose?)
 
I fixed one that had the same issue a while back. Full battery, but low voltage at the truma boiler. Was a bad connection somewhere hidden, so I ran a new fused wire, sufficient to avoid voltage drop, direct from the battery. Easy enough to test with a length of wire. Thinking about it, I ran 2 core to supply live and ground
 
TheBig1 said:
I fixed one that had the same issue a while back. Full battery, but low voltage at the truma boiler. Was a bad connection somewhere hidden, so I ran a new fused wire, sufficient to avoid voltage drop, direct from the battery. Easy enough to test with a length of wire. Thinking about it, I ran 2 core to supply live and ground
Click to expand...
Poor earth connections are a constant cause of problems with MH's. Always worth adding extra!
 
Does this only happen when parked up on your drive or does it also happen when on site?
 
Thanks all. Responses as follows:

Claire Ambler - if you mean the gas solenoid valve, I think this could be a problem. Unfortunately, it’s right at the bottom of my Truma and cannot be accessed without taking the boiler out. Also, it seems to be impossible to find a replacement 30mbar replacement as they are discontinued😟.

Prettyandfluffy - unfortunately Truma in Derby will not do appointments now for boilers as old as mine. As I mentioned earlier in this thread, they will only look at the boiler if I have it taken out of the van and sent to them.

Bessy765 - yes the combustion fan is working.

Ianj - this could be an issue I guess.

L’hobo - I’ll give that a go.

The Big1 - this seems like a sensible suggestion. Where would I put my multi meter probes to test voltage at the boiler?

Potty - haven’t tested heating on a site as haven’t been away in the van since the weather was such that didn’t need heating!

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at the boiler, check the incoming cable, it should be thicker wires, colours vary by manufacturer
 
Bit of an update. Been out working today but got home so thought I would try the boiler again ( more in hope than anything else). So, tried it on the drive ( which is level in case anyone thinks that may be an issue) both with engine running and off and also on EHU and just on Leisure battery - all with same results - would not fire up and red light comes on. Drive van 100 yds down the road, stop and try and start with engine running and not running - same result - red light lock out. Drive for about 10 minutes round the houses and arrive back on drive. Engine off - turn boiler on and fires first time ( whilst not yet connected to EHU) . Re-connect to EHU and left it running perfectly ( blower fan operates at correct 2 speeds depending on internal van temp) for about 45 minutes. Eventually as van has hit correct internal temp the heating turns itself off and, as it should, green light stays on. However when internal van temp drops enough for the heating to fire up again then - you've guessed it - red light lock out. Tried turning it off and on several times but will not re-ignite.
Over next couple of days I will now measure voltage at boiler ( possibly easier said than done as access is not good) and try to take off connections to PCB and clean up with contact spray. If that doesn't work then I think that next step is to send PCB off to A&R Electronic ( who I mentioned earlier in the thread) to check if all OK. If that comes back as all good then I think all I can do next is get my mobile guy to come and take boiler out and do a strip down on it to see what he can find.
 
have you measured the voltage on leisure battery directly ?
 
I will measure tomorrow but as previously mentioned, both my voltage measure thingy in hab 12 v socket and the Rapido control panel are showing Leisure battery at around 13v. Also it wont fire up on EHU either.
 
RichardandKaren said:
Bit of an update. Been out working today but got home so thought I would try the boiler again ( more in hope than anything else). So, tried it on the drive ( which is level in case anyone thinks that may be an issue) both with engine running and off and also on EHU and just on Leisure battery - all with same results - would not fire up and red light comes on. Drive van 100 yds down the road, stop and try and start with engine running and not running - same result - red light lock out. Drive for about 10 minutes round the houses and arrive back on drive. Engine off - turn boiler on and fires first time ( whilst not yet connected to EHU) . Re-connect to EHU and left it running perfectly ( blower fan operates at correct 2 speeds depending on internal van temp) for about 45 minutes. Eventually as van has hit correct internal temp the heating turns itself off and, as it should, green light stays on. However when internal van temp drops enough for the heating to fire up again then - you've guessed it - red light lock out. Tried turning it off and on several times but will not re-ignite.
Over next couple of days I will now measure voltage at boiler ( possibly easier said than done as access is not good) and try to take off connections to PCB and clean up with contact spray. If that doesn't work then I think that next step is to send PCB off to A&R Electronic ( who I mentioned earlier in the thread) to check if all OK. If that comes back as all good then I think all I can do next is get my mobile guy to come and take boiler out and do a strip down on it to see what he can find.
Click to expand...
How frustrating for you.... eventually it should be sorted...🤔🔧

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