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Smoking Webasto Thermo Top C


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My Webasto Thermo Top C is smoking, settings off the CO alarms and turns itself off after a few minutes. I'm wondering what the likely cause is and whether it is worth repairing or whether it is time I replaced it. Please, could anybody with experience with these post their thoughts.

 

The Webasto unit still heats the radiators (when it is not shutting itself down) and the exhaust vents are not blocked. However, over the last few days of use it has quickly gone downhill.

 

An experienced service engineer looked at it and noticed that there was diesel dripping onto the exhaust. He fixed the leak and instructed me to to run the heater for a couple of hours in order to burn off any excess diesel from the exhaust jacket. At the time the fumes seemed to emanate from the exhaust. However, after running for about 1-2 hours the unit shut itself down again and then, after a few restarts, it would only run for a few minutes and plumes of smoke and vapour could clearly be seen jetting from gaps in the units case and from under the units lid. (The engineer had gone home by then.) On occasions the smoke smelt sweet, as if it included burnt anti-freeze. At other times it just smells smokey.

 

So, I have a choice. I'm required to rely on the marina for all engineering work that I don't do myself, whilst the boat is in the marina and they are recommending a removal of the unit for service and fixing. However, I'm expecting this to be expensive and if the unit is at the end of it's natural life then I'm wondering whether I'd be better off cutting my losses and replacing it with a new one. I don't know how old the unit is, we've only owned the boat for 7 months.

 

I'd be grateful if you've seen a similar issue and know what it might be, to help me decide what to do.

 

Here's a couple of videos of the unit running. At this stage the unit was able to operate for a few hours and the smoke wasn't yet emitting from the case in any noticeable amount, it seemed to come from the exhaust and only a little from the case. It has gone downhill since.

 

https://youtu.be/P5FCNUOd0Ro

https://youtu.be/p7kLH1zPb5E
 

Thanks for any help and thoughts that you want to share.

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7 minutes ago, Rick P said:

So, I have a choice. I'm required to rely on the marina for all engineering work that I don't do myself, whilst the boat is in the marina 

 

 

It doesn't sound as if you do.

 

To give you a rough idea, I am aware of a Webasto Top C being replaced with a new Eberspacher Hydronic S3 D4 12V Kit.  The kit was £1350 from Midland Chandlers and a local engineer charged £350 to remove the old one, replace and test the new one.  For the same work, another "provider" quoted nearly £3k.

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9 minutes ago, GRLMK38 said:

 

It doesn't sound as if you do.

 

To give you a rough idea, I am aware of a Webasto Top C being replaced with a new Eberspacher Hydronic S3 D4 12V Kit.  The kit was £1350 from Midland Chandlers and a local engineer charged £350 to remove the old one, replace and test the new one.  For the same work, another "provider" quoted nearly £3k.

Yes, so I'm concerned that the marina might run up a large bill servicing and repairing it, only to leave me with a working, but old unit, when I could replace it with a new unit with minimal labour costs. I'm wondering if removal and replacement is something that a non-specialist like myself could do.

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33 minutes ago, Rick P said:

I could replace it with a new unit with minimal labour costs. I'm wondering if removal and replacement is something that a non-specialist like myself could do.

 

If you do replace it ensure you buy a PROPER marine version, not an automotive one, there are differences in the electronics, but the big difference is in the exhaust.

 

On a vehicle the exhaust has a hole in it to allow the condensate and gas escape below the vehicle and 'lost'to the air.

On a boat, the same exgaust pumps Carbon Monoxide straight into the boat.

 

A marine exhaust has welded joints and no drain hole.

The cheap heaters on ebay are normally reconditioned automotive ones - hence the prices.

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1 hour ago, Alan de Enfield said:

The cheap heaters on ebay are normally reconditioned automotive ones - hence the prices.

Thanks, for the warning. That's useful to know.

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11 hours ago, Rick P said:

Yes, so I'm concerned that the marina might run up a large bill servicing and repairing it, only to leave me with a working, but old unit, when I could replace it with a new unit with minimal labour costs. I'm wondering if removal and replacement is something that a non-specialist like myself could do.

 

In the case I'm referring to there was a need to move the fuel pump, which involved copper work.  Only you know what you are confident in taking on yourself.

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12 hours ago, Tonka said:

Thanks, Tonka. I'll make a note of that. That might be very useful. I've spoken to one of the engineers this morning and he feels it is likely that the issue is caused by a build up of carbon in the unit, so the plan is to remove the unit and service it. Hopefully, if it's beyond economical repair then this will be found quickly.

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I am a deisel boiler engineer and and the carbon issue is the most likely, i have cleaned my own webasto unit of carbon, not to difficult just fiddly.  You can purchase online a USB adaptor that connects your webasto to a windows laptop and with the webasto software that you can find online you can check all the functions of the heater and adjust the CO2% to the correct level (to much co2 and it smokes), but you do need a flue gas analyser to check the co2 value.

If this is outside of your comfort zone it will be reasonably expensive as the unit may have to be disconnected from the water system, electrics and deisel and removed to disassemble the combustion chamber for cleaning, plus necessary gaskets.

With regards to replacement the newest versions from webasto are better able to vary the output to demand than the earlier ones thus operating at the lowest fuel consumption that will still keep you warm and reduces cycling

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I serviced mine before Christmas, symptoms lots of white smoke and diesel smells. Decoked it and all was well. Took a couple of hours but saved a lot and was satisfying. Hardest bit was getting the olive off the fuel feed pipe where it goes into the burner assembly. There's another post somewhere from I guess around October last with details of a download with illustrated step by step instructions.

 

Martin/

 

edit: here: https://www.canalworld.net/forums/index.php?/topic/108552-webasto-service-repair/

Edited by Onewheeler
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On 29/03/2021 at 20:58, GRLMK38 said:

 

It doesn't sound as if you do.

 

To give you a rough idea, I am aware of a Webasto Top C being replaced with a new Eberspacher Hydronic S3 D4 12V Kit.  The kit was £1350 from Midland Chandlers and a local engineer charged £350 to remove the old one, replace and test the new one.  For the same work, another "provider" quoted nearly £3k.

I had the new Eber HS3 D4 fitted a few months back. Super quiet and no cycling!

 

http://www.espar.co.uk/EsparPlymouthProducts_NarrowBoatHeating.htm

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1 hour ago, LadyG said:

Do these things need to be serviced routinely, if so, how? 

 

I was told by a reputable marine engineer that routine servicing can cause more problems as they are quite precise in their assembly.  Long runs with good fuel is as good as any service from what I understand.  Cycling is the problem, made worse by thermostatic controllers.  On/Off with a 1 hour countdown is my approach. 

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54 minutes ago, GRLMK38 said:

 

I was told by a reputable marine engineer that routine servicing can cause more problems as they are quite precise in their assembly.  Long runs with good fuel is as good as any service from what I understand.  Cycling is the problem, made worse by thermostatic controllers.  On/Off with a 1 hour countdown is my approach. 

Tx, mine seems to work OK, I just have it switched ON all the time and adjust the thermostat. I used Hydraboost  at high concentration when my diesel was low volume, it seemed to make less screeching. With lots of clean fuel and additives at standard rate, it seems fine. It usually runs for 35 mins, then turns off, I use it in summer as well, every couple of days to heat water and keep everything circulating, rather than leaving it to decay.l / corrode. Engineer topped up the anti freeze and bled a radiator. Past experience tells me it's best to pay someone who knows what they are doing, though it's not easy to find that person! 

Edited by LadyG
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I would agree with Patron that servicing is a bit a bit of a bind as the unit has to be disassembled, i would suggest that if the exhaust becomes clearly visible either black or white smoke or burner drop outs then attention is needed (will produce a little smoke on start up until warm) other wise the old adage "if it aint broke don't fix it" because it will be broke once you have fixed it. 

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On 01/04/2021 at 16:30, plumbob said:

If this is outside of your comfort zone it will be reasonably expensive as the unit may have to be disconnected from the water system, electrics and deisel and removed to disassemble the combustion chamber for cleaning, plus necessary gaskets.

@plumbob in the end the Marina arranged for a service engineer to do just that. The service engineer's diagnosis matched yours. Maybe I should think about getting the diagnostic kit to fend off issues like this in the future.

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On 01/04/2021 at 19:45, Onewheeler said:

 There's another post somewhere from I guess around October last with details of a download with illustrated step by step instructions.

Thanks @Onewheeler I'll look at that link with interest. The unit has gone to the service engineer now, but if it turns out to be expensive then I may think about learning the skills to save the expense in the future 

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  • 3 weeks later...
On 05/04/2021 at 09:16, Tonka said:

Thanks, Tonka. I'll keep a copy of that for the future. In the end the engineer serviced the Webasto. He found it to be coked up. After servicing and tested on the bench he reported that it worked fine, however, after fitting it to the boat it started smoking. Initially, it was moderate smoke that the engineer put down to water evaporating from the exhaust, but after 45 minutes of running time it was generating clouds of white smoke. The current theory is that either the exchanger is broken and leaking when the unit gets hot, causing it to burn water and antifreeze, or the fuel pump is faulty. If the former is true then I've just paid for an expensive service on something that's beyond economical repair. If the latter is true then my concern is that the faulty fuel pump was the cause of the problem all along and that the engineer's initial advice to run the Webasto for a few hours caused it to be coked up because it was running rich due to the faulty fuel pump. The marina have wisely taken themselves out of the loop on this one, meaning that I'm now dealing with the engineers directly, which is good, but I'm hoping that the engineers don't keep clocking up the bill charging me hundreds of pounds for each guess. Their hourly rate isn't cheap and I'm hoping that they'll absorb some of the costs in their own margins. I'll guess I'll find out shortly.

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  • 4 weeks later...

Thanks for everyone's comments. I'd just like to update you on the issue. The engineers removed the Webasto along with the fuel pump from the boat and it worked perfectly on a bench test, so they concluded that the issue was with the boat's installation. When one of the engineers reinstalled it he found it smoked again, but, after replacing the exhaust, he decided, after experimenting, that the smoke was caused by the air inlet being non standard - it was a section of exhaust. It seemed to run successfully after that and ran through the night, but stopped in the morning. When restarting it from the control panel I could hear the water circulate and the unit hummed slightly, but there was no sound of the fuel pump working, the burner starting or the combustion fan running. After a few minutes it shutdown and I couldn't restart it from the control panel, so I tried removing and replacing the unit's 20A fuse - a trick the engineer taught me. The fuse blew when I did this. I bought replacement fuses, but the next one blew as well. By this stage my total bill was £823, excluding the parts I had bought myself. The engineer returned free of charge and monitored it with his laptop and saw errors logged from the fuel pump and the combustion fan sticking. The unit failed a couple of times when the looms were touched, so the conclusion then was that the looms needed replacing, I decided to do this myself, to save costs, but even just buying the replacement looms cost another £92. After replacing the loom the same issue happened: the water pump ran for a few minutes and a slight hum, but then the unit shutdown; the 20A fuse blew when it was subsequently removed and replaced. The other engineer kindly offered to monitor it with his laptop free of charge because he was in the area and came to the conclusion that the problem was caused by the combustion fan. The combustion fan tone wavered in pitch in a way it shouldn't and the unit smoked, possibly because it wasn't getting enough air. The engineer agreed to fit the new fan for free if I pay for the part myself. Hopefully, this will fix it. I'm feeling more confident that this is the underlying cause of the problem, but disappointed that I've spent roughly a grand so far of parts and labour.

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43 minutes ago, Rick P said:

The engineers removed the Webasto along with the fuel pump from the boat and it worked perfectly on a bench test, so they concluded that the issue was with the boat's installation.

I wonder if they pressure tested the heat exchanger? They can work fine on the bench but if you have an internal leak that may cause all the problems you describe. Have you had to top up the header tank? What sort of corrosion inhibitor is in the system?

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1 minute ago, Mike Adams said:

I wonder if they pressure tested the heat exchanger? They can work fine on the bench but if you have an internal leak that may cause all the problems you describe. Have you had to top up the header tank? What sort of corrosion inhibitor is in the system?

Thanks, Mike. Before the unit started to fail I found that the header tank needed frequent topping up, but I attributed this to a leak on the header tank, which I fixed. The Webasto started to smoke shortly after that and hasn't really been run enough to show whether there is a continued loss of water. The water has blue antifreeze, whether it has additional corrosion inhibitors beyond that, I can't say. I'm not aware of any pressure test being done on the heat exchanger. I hope that's not at fault because then I'm pouring money into a dud! (To be honest it would be cheaper to throw away the Webasto and heat the boat by burning £10 notes.) I guess the logs saying that that the combustion fan failed and the varying change in pitch when it ran made the engineer (and myself) think that the combustion fan was at fault, but, so far every avenue of investigation has taken a wrong turning, so this may be another one. I'm regretting not replacing the Webasto at the outset.

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Oh dear, that,s a sorry tale. I suppose at the end of it you will have more new parts in the thing than old so it should be OK.  Not sure how the CO monitor would be affected by it unless fumes were being blown in from outside but that needs to be watched just in case.  To blow 20A fuses seems to indicate a big 'thing' A stuck fan would maybe cause this but I think the fan would probably have given up by now, worth testing it if its possible as I guess a new fan motor would be expensive. I used to rely on an Eberspacher and when the fan bearings started to fail the thing made a scraping noise as it rotated, I would expect the same noises from the Webasto but I am not very experienced  with these machines.  Good luck with it.

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I'm no expert on these things but I've been running one I purchased on ebay for about £50. The change in motor note could be due to fluctuation in supply voltage (when the ceramic heater goes on you could get a voltage drop), or it could be a bad connection or the motor going out but is could also be due to water entering the combustion chamber, turning to steam,increasing the pressure in the combustion chamber and making the fan work harder. If you disconnect the fuel supply from the burner and try  listening to the fan running that may give you an indication as to the source of the problem. There are numerous versions of these heaters but most of the mechanical/electrical parts are similar the main variations seem to be with the control circuit board. I had a feeling you could get just an exchange unit from Webasto.

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