Truma Diesel heating white smoke

[TheFrenchConnection]

Our Truma D6E  heating/hot water produced a cloud of white exhaust smoke at start up recently, soon diminishing and then dissapearing. Since then there is a very occasional and very small whisp of smoke at start up. Subjectively the exhaust is slightly smellier and, and also subjectively, it seems to be using slightly more fuel.

Before I spend a fortune having our local agents have a look has anyone else experienced this and have any comments?

Thanks

Mike

[onecal]

Hi Mike

Try these simple checks first

Maybe condensation , sometimes also the  flue facing into a strong wind outside  (turn motorhome around and re try)

Check all your inlets on the unit are free and clear. (Nothing blocking them )

Also check the angle of the metering pump is between 15 and 25 deg' delevery direction upwards 

Is there any fault codes and if so, what are they? What year is your Truama D6E

Edited March 12 by onecal

[TheFrenchConnection]

Thanks for that. Interestingly I had contacted Truma's UK help line after I had posted here and their prompt reply today was:

White smoke for up to 2 minutes means the angle of the fuel pump is wrong, any longer and it means there is air in the system. So that issue seems to have fixed itself.
It could possibly be that the fuel pump is getting ready to fail, you'd need to get booked in at a dealer though to have this checked as we can't say anything for sure without inspection-

One of their suggestions was also the pump angle. The system has worked normally since we bought the van in 2017 (2015 registration) and we were on a level Aire at the time so maybe not that.

It was pretty windy on the Aire, wind from behind and probably funneling between two vans so that's a distinct possibility. The inlet and exhaust are clear, I removed a very slight kink

We no longer hear the pump ticking, so unfortunately they could be right and the pump might be on its last legs... booking in to the local agent tomorrow, probably have to arrange a mortgage later!

Mike

Out of interest we had white smoke just once before, and once only. Back in 2019 we were descending into Peso da Regua in Portugal down a very, very steep narrow road (thanks Satnav) needing second gear on the over-run for quite a while for control. Quite a cloud of white smoke on arrival which baffled me at the time - now I realise the pump would have been working uphill at a lot more than 25°!

[onecal]

Hi Mike 

Yes this is a common issue with the diesel pumps if not fitted at the right angle of between 15 and 25 Deg'  Sometimes the move , yes a new replacement pump at this stage may be a good investment  I think the little metering pump is around £150 

PRODUCT REF: 278609
TRUMA CODE : 34020/69600

Regards

Brendan

Edited March 12 by onecal

[John52]

Being a cheapskate I fit the Chinese copies - you can get a new diesel pump like the one above for less than a tenner on ebay,  which works fine if mounted upright.  I have found every fault to be related to the fuel pump mounting, irrespective of what the fault codes say

In my experience the suggested angle of 15 - 25 degrees pointing upwards is not enough to prevent cavitation - air bubbles slowly forming, which even out the spurts of diesel injected into the combustion chamber, so it comes out in a dribble, doesn't vaporise and burn. (White smoke is unburnt diesel)

So I chuck away the supplied mountings and fuel pipe, get some decent quality rubber fuel pipe and clips, and use it to suspend the fuel pump vertically under the heater.  Which makes a good flexible mounting, with the pump outside the van to reduce noise.  You can also use the rubber pipe as the feed from the tank as its not under pressure so no worries about cavitation on the supply side of the pump.  This keeps the bore of the supply side larger and uninterrupted, so less likely to wax up and stop the fuel supply in cold weather.

[onecal]

Hi Mike 

If at all possible replace like with like on your Truma D6E, stay away from the Chinese copies if at all possible. Regarding the angle I have given you re' the metering pump  I can assure it is indeed within manufactures specifications and correct (15-35 Deg).Sorry my initial post should have read 15 - 35Deg. (typo) The 25Deg works very well and is within manufacture's spec' for the Truma D6E

Best of luck with it today

Regards

Brendan

Edited March 13 by onecal

[John52]

This video explains why the best angle for the fuel pump is 90 degrees (i.e vertical as I said)

more detail and proper tests here

 

[John52]

Their practical experience corresponds with my own

i.e problems like the OP has when I mounted the fuel pump at the angle onecal suggests

heater smoking and conking out

But no problems with my Chinese diesel heater in the years since I mounted it vertical (90 degrees) 😃

Default setting is 3 kw and I let it warm up on that before turning it up to full power 5.5kw

Too much fuel when its very cold could make it hard to light

Works a treat 😃

[onecal]

  Truma D6E ????

Hi all 

Rubbish , but then they are talking about Chinese rubbish and these Guys on many a YouTube think they know more than the manufactures of a good product. One does wonder what experience they really have when they actually recommend rubbish like that .But if you want to go and use  with a cheap product , that's your choice Of course they are never to be found if it all goes wrong .

.I think the manufactures of the Truma D6E (as the OP was asking about) know what is the best angle for their product as per attachment 

Regards

[mtravel]

I just remember that the Truma D and various Webastos need to be turned on once a month (in fact I do it every six/eight weeks) for about half an hour.

Turning them off as per the instructions and letting the stove finally turn off by itself (the procedure includes the "washing" phase of the combustion chamber and should not be interrupted).

Max

[onecal]

Hi Max 

Yes using them often, is good for them , also if the unit is fitted to an independent  secondary diesel tank that may not get used regularly to drain and re fill with fresh diesel, especially if the diesel  is over 6 months to a year within the secondary tank (not your engine fuel diesel tank) So yes using them often is a very good practice keeps things lubricated and goes a long way to prevent things gumming up and extending the life of your appliance.

Regards

Brendan

Edited March 13 by onecal

[John52]

1 hour ago, onecal said:

  Truma D6E ????

Hi all 

Rubbish , but then they are talking about Chinese rubbish and these Guys on many a YouTube think they know more than the manufactures of a good product. One does wonder what experience they really have when they actually recommend rubbish like that .But if you want to go and use  with a cheap product , that's your choice Of course they are never to be found if it all goes wrong .

.I think the manufactures of the Truma D6E (as the OP was asking about) know what is the best angle for their product as per attachment 

Regards

 

1 hour ago, onecal said:

One does wonder what experience they really have when they actually recommend rubbish like that .

 

Same practical experience as mine I suppose

As I said it only worked properly when I turned the pump vertical

Now my Chinese diesel heater has been working great for 4 years 

The videos explain why

Can you explain why you think they are wrong and it works better at 15 degrees?

(In the installation Truma suggest there wouldn't be room to mount the pump at 90 degrees

I only did it by mounting the pump under the van)

[onecal]

Hi John 

The OP asked about his Truma D6E , not Chinese rubbish 

25 Deg the manufactures (for TrumaD6E) recommend is the optimal figure  I will attach their recommendations for you again (between 15 to 35 Deg)

If you wish to believe those on YouTube over what the manufacture of Truma D6E  recommends for their product , that's your choice , but it would not be mine 

Look I am delighted your Chinese heater as you say worked so well for you for four years , Sure maybe these guys that make these expensive products and spend a lot of money on R&D no nothing at all and these guys on YouTube (not them all) know so much more , some with very little practical experience, only make sure you ring the bell and subscribe lol 🤣 There you go

Best of luck 

Regards

[John52]

2 hours ago, John52 said:

Can you explain why you think they are wrong and it works better at 15 degrees?

So thats a 'no' then?

[onecal]

The OP asked about his Truma D6E 

This is from that very manufacture ? Surly they are right ?

Again 25 Deg  (not 15 Deg) as you constantly mistakenly quote 🤣

Best of luck with your other appliance 

[onecal]

Hi Mike

These are only the first issues i mentioned and to check first ,that may cause white smoke and as Mtravel  correctly quoted it needs to be run regularly and hot, to heat up properly often , to prevent coking which can prevent enough heat transfer on start up and produce unburnt diesel fuel during combustion

Also the heater plug may not be getting enough voltage on start up due to voltage drop and the screen around it may become coked up also doing same

The small screen (if fitted) be cleaned by removal and burning off the soot in a gas flame (similar to exhaust spark arrestor in two stroke small engines)  Careful full insertion is needed on replacement not to block off the small air hole

I hope you got a positive response today from your repairer and not too costly an outcome 

Regards

Brendan

[John52]

On 13/03/2024 at 18:51, onecal said:

 

Again 25 Deg  (not 15 Deg) as you constantly mistakenly quote 🤣

 

It says 15 - 35 Deg

That means any figure between 15 and 35 degrees.

So 15 is a valid quote

so is 16, 17 , 18 etc - any figure you like up to 35

Can you explain why (any figure you like) is better than 90 degrees?

I am aware of what it says in the instructions - the same as it says in my Chinese copy

But it doesn't work

My heater has only worked reliably since I have turned the pump to 90 degrees

The people in the video have found the same - and they offer a detailed explanation of why 90 deg works best which you appear to have ignored.

So I offer it as a suggestion

Because sometimes you need to think outside the box

I don't know what else it says in the rest of the Truma instructions - probably the same as my Chinese copy

Which says avoid any steps in the inside of the piping (where cavitation could occur) - easier said than done

It also says mount the heater on the floor and the pump inside the van - which rules out mounting the pump at 90 degrees.  But if you get some decent diesel pipe you can hang it by that under the van - making a flexible mounting and quieter inside the van.  Positioning the heater and pump where the pump is protected by box section.  The pump is at the mercy of the weather (perhaps thats why they suggest 15 - 35 deg so it can go inside the van?

But a Chinese new pump is less than a tenner, and mine is mounted where its easy to replace, so I'll risk that.

Since I have mounted the pump that way my cheapo Chinese heater has run trouble free - 4 years now.  Thats a 5.5 kw heater for less than £100 for the full kit. Still working well.  Thats not 'rubbish' is it?

But when I mounted the heater at 15 - 35 degrees it was always getting sooted up and conking out due to fuel issues.

The people in the video have found the same as me - so I offer it as a suggestion as it might help others.

But am I missing something here? - other than that section of Truma fitting instructions which we have seen many times already so please don't keep reposting it instead of answering the question.

I ask again 

Can you explain why (any figure you like) is better than 90 degrees?

 

Edited March 16 by John52

[Derek Uzzell]

Boring, boring, boring....

Truma's installation instructions for Combi D6 heaters make it crystal-clear that the fuel metering pump MUST be installed with its pressure side (delivery direction) sloping upwards and a diagram (posted 3 times by onecal above!!!) indicates that the permissible upwards slope should be between 15 and 35 degrees. What the effect of ignoring that guidance and mounting a D6's pump at a 90 degree slope is anybody's guess, but I'm certain that Truma would not recommend it.

(If you and onecal persist in having the last word in forum discussions, I suggest you get a room.😀)

[John52]

But Derek you are just reposting the instructions again

This is what makes  threads so repetitive long and boring

I just hoped someone could explain why they think 15 - 35 degrees works better

If people would actually answer the question they are asked it could be dealt with in one post - and be informative, helpful and useful.

 

Edited March 16 by John52

[John52]

All the great engineers like Brunel thought outside the box

I realise I am not in their league

But I try to follow their example.

[Steve928]

I suspect that it might have something to do with the volume of fuel that the pump delivers. Above 15 degrees is critical to prevent cavitation/airlocks/whatever, I think we all agree.

Perhaps the pumps only deliver their rated output at up to 35 degrees and above that angle the dose either increases or decreases (I could imagine that it might decrease slightly at steeper angles) and you've chanced upon the perfect angle and hence dose for your installation given perhaps a less precise output from a cheap pump. One of my 2Kw installations is very smoky (white) upon startup and runs a bit rough unless I switch in the altitude setting to decrease fuel input; basically it's over-fuelling - so perhaps I'll try the vertical pump on this to see if anything changes.

Of course this could be bench-tested too just measuring the pump output at increasing angles. One day perhaps..

[John52]

5 hours ago, Steve928 said:

I suspect that it might have something to do with the volume of fuel that the pump delivers. Above 15 degrees is critical to prevent cavitation/airlocks/whatever, I think we all agree.

Perhaps the pumps only deliver their rated output at up to 35 degrees and above that angle the dose either increases or decreases (I could imagine that it might decrease slightly at steeper angles) and you've chanced upon the perfect angle and hence dose for your installation given perhaps a less precise output from a cheap pump. One of my 2Kw installations is very smoky (white) upon startup and runs a bit rough unless I switch in the altitude setting to decrease fuel input; basically it's over-fuelling - so perhaps I'll try the vertical pump on this to see if anything changes.

Of course this could be bench-tested too just measuring the pump output at increasing angles. One day perhaps..

Many Thanks Steve

At last someone answers the question they are asked.

Instead of making the thread long and boring by ignoring the question they are asked and repeatedly telling me to mount the pump at an angle I have already tried and found doesn't work properly.  After its been working great for 4 years with the pump at 90 Deg.  And all those on youtube have had the same experience as me with the pump angle at less than 90 deg.

But back to topic

I think you could well be right Steve.

Clearly mounting vertically minimises the risk of cavitation, air locks etc, and is best for pump lubrication.

But the magnet has to work harder to pull the piston up against gravity and the return spring.

I suppose the ideal might be to mount the pump at 90 degrees with a weaker return spring

But many installations wouldn't have room for that with the heater already on the floor.

So they have to design a pump to work at a shallow angle (stronger return spring)

Even though that increases the risk of cavitation and air locks etc, and pump wear.

Mounting the pump at 90 degrees may well reduce the flow a little as you say - sounds logical to me.

But it still chucks out plenty of heat

And above all - it works - trouble free.

So I suggest it for anyone else having similar problems with fuel supply.

[onecal]

Hi All

Again I think the OP asked about his Truma D6 ..............not a Chinese heater ?????

So lol I was answering the OP question not on a cheap Chinese version 

Again I think they are they experts regarding their product the sell and i have posted an attachment on same (over and over) as proof .

So why one individual here wants to talk about his exploits about his Chinese heaters  which have nothing to do with what the OP be asked about is anyone guess lol maybe just picking holes  and trying to argue over nothing is beyond me. Maybe if it was about a cheap Chinese heater he is the man .   Anyway I hope the OP (TheFrenchConnection) got sorted 

Regards

Brendan

[John52]

Obviously the Chinese diesel heaters work in the same way as the German ones.  But just to point out they are so similar that many of the parts are interchangeable - direct copies in fact.  They appeared on the market as soon as the patents on the German ones ran out.

So basics like the diesel fuel pump and what causes a cloud of white exhaust smoke at start up which was the OP's question, apply equally to all makes, German or Chinese.

[onecal]

Hi All

I really think it would be very foolhardy to fit cheap Chinese parts into a Truma D6, especially if you have to turn some of those cheap parts as mentioned upside down to get them to work ,which is way outside the optimum of 25Deg'  that in fact Truma actually recommend for their Truma D6 ( recommendations are between 15Deg' and 35Deg' )  I hope  Mike  (TheFrenchConnection) reports back to us to tell us how he  got on with his Truma D6 as indeed not only the pump angle can cause white smoke on start up . Hope he reports back 

Regards

Edited March 18 by onecal