Rick P

I don't know. I struggled to follow the wiring from the stop button to the solenoid. I'll have another go. Thanks, PD1964. They could be really helpful. It's a Barrus Shire 2002E

Thanks, Mike. I'll try running it with no fuel supply connected. I hope to get a diagnostic kit soon, which will allow me to run the fan in isolation, but it's being posted from Bulgaria, so may not arrive in time.

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.

Thanks, for the warning. That's a really good point. I didn't think of that.

When my Webasto Thermo Top C diesel heater developed a fault it filled the boat with CO. We have three CO monitors and they were all set off at different times, sometimes two at a time. However, I've been told that normally a Webasto doesn't produce much CO, so maybe, if your CO monitors aren't detecting CO from your heater, then it's not that they are inadequate, but that your heater is in good condition. I can confirm though that the alarms are not set off immediately. They seem to wait until a certain limit of CO exposure has been reached. One of my alarms shows the part per million on a digital screen, which is reassuring when it shows 0 and gave me the impression that it's not the level of CO (at low levels) that triggers the alarm, but rather the amount of exposure to CO over time. For peace of mind, multiple CO monitors helps.

The stop button on my narrowboat stopped working last weekend. My narrow boat has a Barrus Shire engine and a stop solenoid that is very similar to this one https://www.amazon.co.uk/Holdwell-Solenoid-1510SP-12ETS-SA-4786-12-Yanmar/dp/B07BBFXS4Y Unfortunately, whilst investigating the issue I think I may have dropped the stop button into the marina waters. (I disconnected and put it down, but later lost it. It was nowhere to be seen - even in the bilges.) The button worked before it went into the drink, so this wasn't the cause of the problem, so the issue must be caused by either the solenoid or the wiring between the button and the solenoid. (I can stop the engine using the manual button on the solenoid.) I was wondering if I could test the solenoid by stretching it across the terminals of a battery, but I'm not sure which of the leads is negative and which is positive. (Both are black, although one has white writing on it and, unlike the one in the link, both have separate tabs.) If I test it by stretching it across a battery will it be damaged if I were to get the polarity wrong, does anyone know? Aany help will be appreciated.

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.

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.

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

@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.

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.

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

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.

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.