Truma Diesel Heater Stain

[MiniNick]

Hey everyone.

Just installed a new Truma Combi 6DE (diesel heater) to replace or old gas one. everything went well and it works great.

But Truma provided a black exhaust cap, which didn't suit or can so I reused the old white ones. But over the last couple of weeks the had been a brown stain occuring.

Is this normal for a diesel heater, hence the black cap, so you cannot see it, or am I over fuelling it (that was my first thought)?

Cheers

Nick

 

[canopus]

The gas variant creates more condensate apparently.

Plus a bit of regular elbow grease doesn’t go amiss.

You need one of these. EBay or Amazon.

https://www.ebay.co.uk/itm/26617127...pid=5339023013&customid=&toolid=10001&mkevt=1

 

[fishplug]

Does it smoke when running?

A small amount on startup is normal, but it should burn clean when up to temp.

 

[MiniNick]

No white smoke at all, the exhaust gases are clear. There is a tiny bit of a diesel smell hence the thought of over fuelling.

Definitely need the exhaust deflector if this continues.

 

[Outofyorkshire]

Our D6E has not put out anything like that. It is a first gen with the square powered flue tho, so not sure if that makes any difference.

 

[Pausim]

I believe the diesel flue is slightly different and you need to use the correct one. Diesel produces more condensate than lpg, there is significantly more energy in a litre of diesel than a litre of lpg and it burns differently. They fit the same hole but it is possible Truma make them different colours so that they don’t get mixed up. Perhaps nigelivy or RogerIvy could advise?

 

[RogerIvy]

I believe the diesel flue is slightly different and you need to use the correct one. Diesel produces more condensate than lpg, there is significantly more energy in a litre of diesel than a litre of lpg and it burns differently. They fit the same hole but it is possible Truma make them different colours so that they don’t get mixed up. Perhaps nigelivy or RogerIvy could advise?

The exhaust flue is quite different from the LPG heaters. The LPG have a simple tube within the intake tube. The diesel exhaust has a small inner tube surrounded by heat resistant insulation type material and then an outer tube … all of this within the intake tube (which is very similar to the LPG model).

In a nutshell, the LPG and diesel flues are not interchangeable.

 

[Pausim]

MiniNick it sounds like you need to use the correct flue. I wouldn’t fire up the boiler until you have put this right.

^{_{Subscribers  do not see these advertisements}}

 

[PDrill]

Our diesel Truma has a dark grey flue and it also "changes color" a bit after a while, I would think if it was white it would look like yours in the picture. Every now and then I clean it with Autoglym Intensive tar remover. Doesn't make it new but much better.

 

[Pausim]

Our diesel Truma has a dark grey flue and it also "changes color" a bit after a while, I would think if it was white it would look like yours in the picture. Every now and then I clean it with Autoglym Intensive tar remover. Doesn't make it new but much better.

It is not just the colour that is different, the diesel cowl comes with an O ring to help manage the additional condensate.

 

[MiniNick]

MiniNick it sounds like you need to use the correct flue. I wouldn’t fire up the boiler until you have put this right.

Sorry I wasn't clear in the first message, the exhaust/flue is the new one that came with the diesel heater (as you are right they are slightly different), the only thing I swapped was the coloured cap on the end (the bit of plastic). The kit came with black cap and I already had the white one, so did the swap (they are exactly the same in terms of size/shape etc).

I doubt the end cap is causing the issue, but i do wonder the reason they give you the black one is to "hide" the staining.

 

[Pausim]

Sorry I wasn't clear in the first message, the exhaust/flue is the new one that came with the diesel heater (as you are right they are slightly different), the only thing I swapped was the coloured cap on the end (the bit of plastic). The kit came with black cap and I already had the white one, so did the swap (they are exactly the same in terms of size/shape etc).

I doubt the end cap is causing the issue, but i do wonder the reason they give you the black one is to "hide" the staining.

Did you use the O ring that comes with the gas cowl on your white one?

 

[MiniNick]

Did you use the O ring that comes with the gas cowl on your white one?

Hmm..... i want to say yes, but now i am going to dig through all through the bits and bobs and check!!

 

[MisterB]

How does the O ring manage the condensate? If condensate is produced it has to go somewhere and I assume it's exit point is through the cowl, hence the additional spout to direct it away from the bodywork

... I think that on a domestic gas boiler the flue is arranged to let the condensate return to the boiler but that isn't the same arrangement on a Truma diesel to my knowledge.

 

[Lenny HB]

The kit came with black cap and I already had the white one, so did the swap (they are exactly the same in terms of size/shape etc).

Most likely they are made from different materials and the white one is not suitable for the diesel exhaust gas.

 

[Pausim]

How does the O ring manage the condensate? If condensate is produced it has to go somewhere and I assume it's exit point is through the cowl, hence the additional spout to direct it away from the bodywork

... I think that on a domestic gas boiler the flue is arranged to let the condensate return to the boiler but that isn't the same arrangement on a Truma diesel to my knowledge.

I found this on the internet.

“The Truma D6 (diesel) cowl requires an O-ring while the LPG cowl does not because the diesel system produces a high amount of condensate, and the O-ring serves to seal the cowl against leaks of this liquid.

-Diesel (D6) Condensate Management: Diesel exhaust produces significant water vapor during combustion. The O-ring prevents this condensate from leaking out of the exhaust cowl onto the motorhome's sidewall, which could cause stains.

-LPG Differences: LPG combustion burns much cleaner, resulting in very little moisture. Therefore, a sealed O-ring at the cowl is not required to handle condensation.

-Interchangeability: While the cowls themselves can be swapped (e.g., this black version fits both), using the wrong type or not using the O-ring on a diesel unit can result in condensate runoff.”

^{_{Subscribers  do not see these advertisements}}

 

[MisterB]

So it looks like the O ring is a seal that stops the condensate leaking out from around the cowl and down the bodywork, which means it is directed out through the cowl itself hence the need for the drip extension.

 

[MiniNick]

Most likely they are made from different materials and the white one is not suitable for the diesel exhaust gas.

Yeah that might be the case, also the white one is 17 years old (as i think it came with the Truma Combi 2 gas unit in the van). So maybe the plastic is slightly knackered too...

So it looks like the O ring is a seal that stops the condensate leaking out from around the cowl and down the bodywork, which means it is directed out through the cowl itself hence the need for the drip extension.

So if i understand that right, the o-ring stops it leaking before it comes out the cowl, i.e. around the gap between the cowl and the flue. But since it is coming out of the cowl then it is doing the right thing.... if that makes any sense.

 

[Pausim]

I have noticed that my diesel boiler gives off more obvious condensation in the exhaust fumes when it first fires up than my lpg one did. After the initial firing up the condensation is less obvious and the exhaust fumes are similar to the gas fumes so it is probably in this initial period that the O ring is needed.

I Googled for information on this and learned that the diesel flame and gas flame burn at similar temperatures but the gas flame instantly achieves the high temperature but the diesel one takes a little longer to get really hot. Presumably the diesel exhaust gasses are also slightly cooler in this initial fire up and the condensate is therefore more obvious, resulting in the need for more careful handling during the first fire up.

 

[MisterB]

I have noticed that my diesel boiler gives off more obvious condensation in the exhaust fumes when it first fires up than my lpg one did. After the initial firing up the condensation is less obvious and the exhaust fumes are similar to the gas fumes so it is probably in this initial period that the O ring is needed.

I Googled for information on this and learned that the diesel flame and gas flame burn at similar temperatures but the gas flame instantly achieves the high temperature but the diesel one takes a little longer to get really hot. Presumably the diesel exhaust gasses are also slightly cooler in this initial fire up and the condensate is therefore more obvious, resulting in the need for more careful handling during the first fire up.

I read somewhere that starting it on electric (if possible) and then switching to diesel wants it's 'warm' helps reduce the condensate