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Help Please - can smell propane when boiler on


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We bought our first motorhome last week. Weve had campers before.

We have got a 1996 Peugeot boxer A class pilote galaxy MX88. This uses propane for the heating etc.

Anyway, we took her away this weekend to try her out after having a full habitation chack on her Thursday. She passed with flying colours so am a little confused as to why when we put the water/heating boiler on we can smell propane.

The boiler is under the seat/bed at the rear and this is where it smells. Is this normal. It was the first time th boiler has been on for an amount of time since last year we believe. It was all tested in the habitation check.

Many many thanks, we are a bit worried

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you are right to worry! you should never smell gas! get it back to the people who did your hab. check asap and get it sorted though it may be something that has developed since your hab check though doubtfull they should not charge you for the recheck


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Are you nearing the end of a cylinder by any chance?


If so the 'smell' (which is added to the otherwise odourless gas) tends settle at the bottom of the cylinder resulting it in being much more noticeable when nearing the end of a cylinder. I can always tell when we are about to run out as I get a strong whiff shortly before the cylinder expires.

If this is the case then try using a new or much fuller cylinder to see if the smell clears.



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Your Pilote will probably have a Trumatic C-6000 combination air/water heater.


You say that you think the heater has not been operated on gas for any length of time since last year. When this type of heater has not been used for a while, it would not be that unusual for it to be smelly when initially started up, particularly if it is employed just to heat water via gas.


However, if you can actually smell gas when the heater is running, coming from the under-seat/bed area where the heater is located, that’s another matter entirely and I would definitely consider this abnormal (and dangerous).


You need to have the smell investigated asap by someone familiar with motorhomes and this type of heater who can confirm whether the smell you have identified as “propane” (and the smell of bottled gas is fairly recognisable) is due to a gas leakage of some sort or just the result of the heater getting properly hot after a long period of non-use. (I would have expected whoever performed the habitation service last week to have leak-tested the gas system and to have run the heater for a while, but they might not have run the heater long enough to get it really hot.)


Talk to whoever carried out the habitation check, tell them that you can smell gas and insist that the vehicle be rechecked. Don’t delay - do it now!

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Thanks for all your replies. I have spoken with the company who did the habitation check. When the check was done the boiler was put on to warm up, takes about 30 to 40 mins. I do have the trumatic C series that has the boiler under the bed at the rear.

The smell was there on and off and the guy who did the habitation check says to re evaluate and see if it happens all the time. He seems to think that its when the boiler is kicking in. It is a brand new bottle of propane, although i am not certain if the smell was there on the old one or that it just didnt heat up enough.

It doesn't smell all the time. We have turned it off for now but could only smell it when the boiler was on.

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My own sense of smell must a poor thing and my O H seems to have superhuman smell sense, just as she has very sensitive hearing, which is why I get accused of snoring - so most of the time when she raises a suspicion and I fail to detect it I say "yes dear" and then do nothing else. However there was one occasion when she kept insisting there was a smell of gas near the habitation door and after several prompts I did manage to smell gas by sticking my head right inside the nearby gas locker - and a union on one of our BBQ point joints was indeed leaking a tad. No noticeable increase in gas consumption, but her nose turned out to be as good as proper gas leak detector spray to discover a miniscule leak.


I was so impressed by Peter Hambildon finding the leak by using this stuff that I bought a can for next time and happily it has performed superbly - no hint of any gas leak has needed testing ever since.


The point I suppose is that LPG has a very prominent and distinct smell when present in any quantity and can be detected (at least by OH's) at very low (no explosive) concentrations. A potentially explosive concentration of LPG can probably be smelt by mere husbands and MHs have very good downward vents to prevent the accumulation of LPG - so maybe unless you are sure it's gas you are smelling, consider other explanations.

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If it really is gas leaking somewhere, mix a drop of washing up liquid with a glass of water and shake it up to get bubbles, then brush this over each gas connection you can find and look out for teltale bubbles . Make absolutely sure there are none, and whatever else you may do, DONT SMOKE at the same time..


the odour of gas is deliberately added so that any leak is detectable in an extremely low concentration, by most noses.


dont take c hances, get it back to dealer if you still cant find it yourself.




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StuartO - 2015-03-09 4:17 PM


...MHs have very good downward vents to prevent the accumulation of LPG - so maybe unless you are sure it's gas you are smelling, consider other explanations.


Although UK-built motor homes have, historically, been fitted with gas ‘drop-vents’ near gas appliances (presumably to conform with traditional UK caravan-building practice) it would be very unusual if Pilote (or any other Continental European motorhome constructer for that matter) had installed a drop-vent near to a Truma C-Series heater.


This type of heater is designed to take in air from within a leisure-vehicle’s habitation area, heat it and then blow the warmed air back into the habitation area. This recirculatory process maximises the heater’s efficiency and any aperture that’s near to the heater and that leads outside the leisure-vehicle will result in the heater sucking in air from outside rather than recirculating it. I have seen (in a UK-built motorhome) a Truma C-Series heater with a yawning drop-vent next to it and a notice warning that the vent must never be covered. But that was a long time ago and UK converters nowadays usually make some effort to follow Truma’s installation instructions.


The stenching agent added to LPG is normally ethyl mercaptan. This is detectable by smell at concentration levels as low as 1 part per billion, but (apparently) it is added to LPG at a minimum concentration of 20 parts per million. Mercaptan has been described as having the stench of rotting cabbage or smelly socks. In Emma’s case, it might be worth her letting some gas escape from the bottle (eg. by loosening the connection at the bottle’s outlet valve) and comparing the smell of the gas fromtthe bottle with the smell that has been detected inside the motorhome.


Tony’s leak-finding suggestion is fine if a gas connection were leaking, but a Truma C-Series heater has a solenoid valve that allows gas to enter the appliance and I’m doubtful that the washing-up liquid technique would necessarily reveal a valve-related problem. It also needs to be borne in mind that the heater (assuming it’s the original one) is now some 19 years old.


Personally, I’ve no difficulty detecting the presence of propane/butane bottled gas by its smell and I’m sufficiently familiar with Truma C-series heaters to discriminate between a ‘hot heater’ smell and a gas smell.


It makes some sense to experiment with the heater to see if the smell goes away with use, but if Emma thinks the smell is gas-related, there’s a good chance that it is. The smell should not be ignored and, as she is concerned about it, the wisest thing would be to demonstrate the problem to the guy who carried out the habitation check and obtain professional confirmation that everything is OK.

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Many thanks for this in depth reply, i really appreciate it. It makes a bit more sense. I am a bit worried that the person who did the habitation check says its nothing to worry about and that he will charge to come back out. But then again safety is more important than moey.

Thanks again

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Came across this on the internet. IS this my heater? C3402 from 1996 . Is it dangerous

0454/06 Germany

Heating appliance Truma

Type/number of model: Heating systems, authorisation numbers:



National authorisation number S 300;

Trumatic C 3402 (E);

Trumatic C 4002 (E),

Trumatic C 6002 (E)

and Trumatic C 6002 EH,


Factory numbers:

C …. 16 255 001 to 17 159 000

C EH…. 15 329 001 to 17 159 000,

Country of origin: Germany.



These products pose a risk of fire and injuries.


In pure hot water mode (summer mode), it is possible that the heating system may overheat, which in extreme cases may lead to a fire in the vehicle interior.


A possible malfunction of the heating system can lead to the overheating of casing parts. In extreme cases, this may lead to a local fire. The thermal overload can lead to a noticeable smell developing. The manufacturer recommends not using the heating system until it has been examined.

Voluntary corrective actions taken by the importer.


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The information you found on the internet relates to a batch of Trumatic heaters that were manufactured from 2003 onwards. So, in principle, the warnings will NOT apply to your heater.


However, the big difficulty trying to answer your questions accurately without being able to inspect your Pilote is that there’s no certain way of knowing which model of Truma heater is fitted to it unless you can identify the model of heater yourself.


A 1996 Galaxy would have been built with either a Trumatic C-3400 (3.4kW output) or a Trumatic C-6000 (6.0kW output). As you’ve mentioned running the heater on electric, it may be assumed that your heater is the version with a 230V mains-electricity water-heating ‘collar’. Consequently, if the heater is original, it should be either a C-3400(EL) or a C-6000(EL). The snag, though, is that, when a 1996 motorhome is involved, there’s always the possibility that the original heater might have been replaced with a later model.


There ought to be an identification label on the outside of the heater, though it may be positioned where it’s very difficult/impossible to read it. However, if you can’t find/read the label, you may be able to identify the heater from what it looks like.


You can download documentation for Trumatic heaters from here




and, as you’ll see from the pictures, there are visual differences between the C-3400/C-6000 heaters and later Trumatic heaters.


If we assume you have a C-3400(EL) or a C-6000(EL) heater, if you haven’t got Operating Instructions for it, you can find them here




You could run the heater on 230V mains electricity, but it would be a waste of time regarding the ‘smell’ issue. The mains-powered water-heating ‘collar’ wraps round the outside of the heater’s water reservoir and won’t (or shouldn’t) produce any smell when operating. You need to be aware that it only allows WATER to be heated. For blown-air heating you need to run the heater on gas.


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