Smell from truma Boiler Combi 6

[john.mcnamee]

We have a problem with an acrid smell from the blown air vents from a Truma Combi 6 Boiler, in a Swift Bolero 680 FB, under 2 years old.

 

The same/similar problem has been reported on a number of internet forums.

 

Has anyone found a satsifactory cure? (I've not seen one, other than resigned "we'll have to put up with it!" solutions).

 

The specific problem arises when the water heating is on, and is more prevalent on electric only heating. (The smell gets dispersed by the blown air heating, but into the van, causing an unpleasant and eye watering atmosphere).

 

The dealer sent the boiler back to Truma, who returned it, stating there was nothing wrong with it.

 

I contacted Truma technical, who recognised and described the problem without much prompting. They confidently told me the problem was short, blown air pipe runs, and that I should extend them to a minuimum of 1.5m to create a heat sump.This I did. The problem persists.

 

I've rung them again, and they now want a photo of the installation.

Various explanations have been suggested:

plastic swarf in the pipes

dust in the pipes

intermittent use

poor installation

short pipe runs.....

 

I fear there is a fundamental design problem and the heating element gets too hot, which generates the smell - hot metal (aluminium) perhaps.

 

Anyone got any ideas??

John

[bolero boy]

Cant help much except that we have had a couple of issues with our Combi, mainly turning itself of (now cured, we think) and a distinct lack of puff at the cab end, which is a long run from the boiler.

Incidently, I suspect you have a Combi 4 unless there has been an upgrade as ours is a Combi 4 in a standard 2010 680FB.

Chris.

[colin]

I'm not sure it's hot metal, more like hot plastic to me.

Another thing to look out for is rising pipes, Truma say the pipes should 'drop down' from the combi, or have a 'dip' from what I've seen very few if any convertors install these units as per Truma's instructions.

[hallii]

It sounds like chemicals used in the pipework, paint, plastic or something else is coming off as vapour when it gets hot.

 

Have you tried running it for a couple of days on hot when your not using it to see if it starts to go away?

 

H

[Caddies104]

Hi John

There are other threads from past posts, if you go into :-

Search and put say Truma Smell, and then posts over last 12 months, you may find answers in there, good luck

 

 

[jhorsf]

I expect it will not be truma's problem just like the regulators

[bob the builder]

Hi John - Re your combi , I have one fitted in my auto-trail and I have experienced similar smells when I use the electric heating, particularly the facility for heating the water. There have been over the years similarly comments in the MMM and related mags, but never with a definitive solution. In my experience it was the the smell of burnt carbon, quite startling. It is possible that the thermostat is at fault, but I dont get the smell every time. My answer = make sure that the boiler unit has plenty of ventilation around it, do not be tempted to store articles in the same lockyer space. Secondly, I only leave my water heating for a limited period at 60 degrees, as this seems to be the issue, I have no smells at 40degrees. I know that one response was to check that your builder had put in a second vent tube. On my heater I have a venting tube opening into the living area, which is not part of the blown air heating system. apparently, this has not been installed by some builders. remember Trauma biolers have over heating cut offs and related safety features. Having lived with mine for 5years, i now recognize when to manage the system. Best wishes Bob

[Chudders]

Got the same smell and had it ever since having the motorhome,, also had it on the last motorhome.

Worse when on 60 degrees water only but I gave got used to it and this lets me know when the water is up to temp. I wanted to check whether it was overheating and not cutting out so got a thermometer in the water in the sink and found it to be almost exactly 60 and continuously so. I just reckon its the insulation material and construction materials that smell a bit when getting hot.

[Derek Uzzell]

This was a well-recognised characteristic of Truma's now-superseded C-series combination air/water heaters, eventually culminating in a major recall.

 

I was under the impression that the current "Combi" design had fully addressed the C-Series basic 'smelliness' problem - use of plastic materials that were insufficiently heat resistant - so it's disappointing to learn that Combis can still be smelly.

 

I hesitate to be a Prophet of Doom, but I wouldn't be confident that a 'smelly' Combi can be satisfactorily cured. They will tend to smell a bit if not used regularly but, if the installation is not too outrageous and the air-trunking runs are reasonably long (in priinciple they should all be roughly the same length) then, if the appliance still smells when heating water, it's likely to keep doing this indefinitely.

[trebor01]

I have got a truma combi 6 in a Swift challenger 554 caravan 2014 model year with same problem the smell I am getting is burning electronic circuit board. It happens only when the water is heating up. I know this smell because I have worked in electronics for 20 years the smell is the fibreglass resin and matting in the PCB burning and charring cause usually by some over heating components probably in the water heating circuit. The dealer tried to fob me off at first saying it was nothing to worry about. I told him that I though the smell was burning electronics. so the Van is going in on Saturday I am going to ask that all the circuit boards including power supplies connect with water heater are visually checked for signs of charring and burning and if found replaced

[colin]

trebor01 - 2014-05-28 9:57 PM

 

I have got a truma combi 6 in a Swift challenger 554 caravan 2014 model year with same problem the smell I am getting is burning electronic circuit board. It happens only when the water is heating up. I know this smell because I have worked in electronics for 20 years the smell is the fibreglass resin and matting in the PCB burning and charring cause usually by some over heating components probably in the water heating circuit. The dealer tried to fob me off at first saying it was nothing to worry about. I told him that I though the smell was burning electronics. so the Van is going in on Saturday I am going to ask that all the circuit boards including power supplies connect with water heater are visually checked for signs of charring and burning and if found replaced

 

Yes it smells like that, but it isn't. The pcb is well away from the heating element and not conected to the blown air system. I keep meaning to fit longer ducting to the two shortest ones on our van but haven't got a round tuit as we seldom use the water heating only. If I remember I close the two closest vents on the blown air system and it 'solves' the problem.

[Derek Uzzell]

trebor01

 

Welcome to the Out&AboutLive forums.

 

If it were the PCBs producing the smell, it’s likely that the smell would be evident when your Combi-6 is operating in blown-air mode, not just when water is being heated.

 

As Colin says, a Combi’s electronic boards are positioned well away from the heating components, as shown in the drawing (I’m assuming your heater is a Combi-6E) on Page 12 of this link

 

http://dealer.truma.com/_anweisungen/Truma-Katalog/pdf_verzeichnis/30_000/34020_29300.pdf

 

As I said in my posting of 9 March 2012 9:39 AM an acrid smell when the appliance was operating in water-heating mode was a well-known characteristic of the Truma C-Series range that was superseded by Combi and (following a number of serious ‘melt downs’) was ultimately addressed by a wide-spread recall, a change in materials and a design modification. The smell produced by a ‘smelly’ C-Series heater was exactly as was described in this thread in 2012 and by you now – an unpleasant charring-plastic stink.

 

In the original posting (OP) of 8 March 2012 Truma suggests that the problem may be due to very short blown-air trunks where, effectively, there’s an opening directly into the Combi’s interior heating-chamber. It’s not the greatest of ideas having ultra-short trunks, but it will be seen from the OP that, despite the lengths of the heater’s air-trunks having been extended considerably, the acrid smell did not disappear.

 

Other Truma suggestions were mentioned in the OP but, as ‘john.mcnamee’ (who also posted here)

 

http://www.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Truma-Combi-4E-Heater-Smell-/24458/

 

has not logged on here since April 2012, we shall probably never know if the reason for his problem was ever satisfactorily identified and/or cured.

 

You are right not to tolerate your heater producing this unpleasant smell and to ask your dealer to check for signs of overheating. However, unless the installation in your Swift caravan diverges so radically from Truma’s recommendations (and, it has to be said, that’s quite possible!) and there is so little ventilation where the heater is housed that the appliance as a whole overheats, I’m doubtful that the PCBs are the culprits.

 

Could you please provide a follow-up on this when your dealer has inspected your caravan and (hopefully) it has been discovered what is causing the smell? A Truma Combi heater is pretty much the norm in motorhomes nowadays and is becoming fairly common in caravans (a major mistake in my opinion). Consequently, if smelly water-heating is a recognised risk with Combis and the reason for this has been identified, a lot of motorhome/caravan owners will be interested.