Q: When is your heater most likely to fail?

when you say its working now, are ypu using has even though youre on ehu, or are ypu saying ypuve switched to electric?

as i started reading your post my first thought was a duff leisure battery.

easy way to check....pull put your ehu plug and see if this makes any difference to starting the heater on gas.

you could also check the actual leisure battery voltage with a voltmeter across the terminals after its rested (off Ehu for while)...

could be a change in wind strength or direction thats made a difference...

LPG (if bought in the UK) will be mostly Propane and shouldn't have a problem gassing off.....Ive used ours (LPG gaslow) on gas for a bit and no troubles there.

All of this is pure surmise and needs checking plus not meaning to grannies and eggs you.

If it's not obvious you should get a Gas Safe tech to look at it?

Unsure composition of LPG for refillable system but should be OK as cars have to use it in cold weather. If butane, it is poor at gassing off at the  low temp you mention. If propane this shouldn't happen

Were ALL of the cooker rings working - even if this is the case, they may fail after a short time as the bottle can't get enough heat to allow butane to gas off reliably or it is a supply fault?

When it goes off, does it gradually die down (gas supply issue?) or does it suddenly go off with a click as the flame failure device drops out because the thermocouple in the pilot flame is faulty or the pilot itself.

Corrosion on the thermocouple where it enters the gas valve or the gas valve itself - expensive so thorough diagnosis needed!

AFAIK, heater is independent of leisure battery it has it's own cell to start it up.

How old is the system (older = more likely that you have a faulty part?)

Blocked pilot/flue/inlet with spiders webs/leaf etc. (unlikely but should be checked and serviced to rule out?)

Interested in other suggestions and final solution...

...if it were the room thermostat failure (0-10 dial, I'd expect the pilot to stay on reliably but the main gas burners to shut off/go low as the device thinks it has come up to temperature.

As you say the pilot goes out, it looks like a supply issue to me or thermocouple/pilot/gas valve issue.

It does sound like the symptons of the gas not vapourising. Autogas is usually a blend of propane and butane  and varies in country of supply UK is usually propane but other counties can be more butane in the summer, you may have a summer mix in the bottle if you filled it abroad, Vehicle gas systems run liguid gas to a vapouriser heated by the engine so are not affected so much just have to start and run on petrol until warm.

Not sure if this is any help https://www.youtube.com/watch?v=-1m1gwmxHxU

David

Thanks for the replies. 

Reading through them and info on other forums, a likely cause is too much butane in the LPG mix caused by frequent top-ups combined with use in cold weather, and/or a continental fill-up (where they have more butane in the mix). 

Butane apparently only 'gasses' above 0 degrees - below that you are just burning the propane in the LPG mix, leading to a gradual accumulation of butane sulking in the tank in liquid form.

However, this doesn't account for the cooker burners working when the Truma wouldn't.

If the problem is too much butane, the answer seems to be to empty a cylinder before refilling (to burn off the accumulated butane), while in the meantime putting a hot water bottle in the gas locker!

I take it that you are useing red propane gas cylinders, and not blue butane cylinders as butane will not gas up if temperatures get to below about 5c

hes using a gaslow refillable hence the comments abput the posibble mix of gasses.

however, unless the fills have been recently from the continent, this wont ba an issue, i had been using mine back here on 'spanish' lpg for a bit with no problems.

we now need the OP to try a few tests..

along with confirming the system now runs (on gas we need to know) with an ehu plugged in. if working, this will point at a poor leisure battery.

also, running with ehu removed, but with a borrowed propane bottle will eliminate any problems with the gaslow lpg.

gradual process to eliminate the usual easy suspects before diving in for an engineer.

also, no one has mentioned the classic symptom of faulty regulator. ive read that hobs might run with a reg problem but the larger sullpy of gas required by the heater cant be satisfied, hence probs with heater but hob running ok.....again, someone may have a spare reg tontest with..

good luck.

any update Cross trail?

I had similar problems with my S3002 when on gas and in windy conditions.  I read on another forum that fiiting an extension flue would help, which it did and I've not had any problems since.  The extension is 6 inches long and just screws onto the top of your existing flue.