Truma C3402 / C6002 Lockout help please (in Spain)

[Parapilot]

My system was working fine until recently (mainly for water heating but occasionally blown air) but has been causing problems for the last week or two and now refuses to work at all.

Turning on the dial gives the orange and green lights for start-up, the burner fans, gas and ignitor works and it will start up briefly before a loud click as the gas shuts off, leaving a red and green light on the dial. Turning it on and off repeatedly has worked for the past couple of weeks, even until yesterday - where after a couple of dozen attempts it all works perfectly again and gives plenty of hot water and/or blown air. I've been resetting it for over an hour today and it completely refuses to run.

I've read various threads on the subject but the intermittent nature of the fault has me confused. It sounds like some sort of flame sensor or PCB problem is causing the gas valve to shut off. I've removed and examined the PCB but cannot see any obviously damaged or burned out components. There is no way to access anything else without completely removing the whole unit - which looks a complete nightmare in such a confined space.

The exorbitant price of parts makes it unrealistic to just start randomly replacing things like PCB etc in the hope of getting it working, so any ideas or suggestions would be greatly received. Alternatively, does anyone know of any Truma repairers in Andalusia (between Cadiz / Malaga or wherever) that are reliable and not overpriced ?

Thanks

 

[Lenny HB]

Are you using Spanish gas bottles or filled up your bottles in southern Spain. Spainish bottles are normally butane and LPG pumps can be a mix of up to 65% butane.
Combi's often fall over on butane even when it's fairly warm, butane can't deliver the flow rate required.

 

[Parapilot]

I have an LPG tank - still half full. Everything else works perfectly including the Alde underfloor heater. It's certainly not cold here but maybe I'll test it again later when the air is hotter just to see.

 

[Lenny HB]

it

I have an LPG tank - still half full. Everything else works perfectly including the Alde underfloor heater. It's certainly not cold here but maybe I'll test it again later when the air is hotter just to see.

It's not just the temperature it's the gas flow rate which is lower for butane. Butane/propane mix varies dependant on time of year & where you are, fill up in the mountains it will probably be 95% propane, fill up in Benerdorm it could be 65% butane.

 

[Parapilot]

It's not just the temperature it's the gas flow rate which is lower for butane.

I'm sure that's true but it still won't work in 18 degree temps and never had this problem during years of travelling around Europe and going high into the Alps, so I suspect it's something wrong with the boiler.

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[gus-lopez]

. Alternatively, does anyone know of any Truma repairers in Andalusia (between Cadiz / Malaga or wherever) that are reliable and not overpriced ?

I am sure @ianthebuilder used some company down that way for his van.

 

[dave newell]

Best guess, and it is just that albeit an educated one, is foreign bodies have accumulated in the combustion chamber. I've had this before and it was an accumulation of dead flies on the burner face. The other possibility is burnt out igniter and flame sensor electrodes. Both problems require a full strip down to rectify.

D.