Diesel Heater smell

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Slipperman

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I have a Mikuni MY16 heater, with 2 outlets. I don't use it that much, but after 4 years ownership I find that though the heater chucks out warm air efficiently, it has a smell to it. It isn't a dieselly or fumey smell (that would obviously be dangerous), but is, I think, the smell of the plastic tubing. I have tried running the heater at full temperature for a couple of hours at a time, but after several attempts I can't say it is noticeably less smelly. I can more or less put up with it, but my other half objects strongly! Any ideas? I did wonder, for instance, if I could fit an air freshener type cartridge (like you sometimes see in cars) next to the outlet? Any other ideas?
 
Depending on the design, it is possible that some exhaust gas is getting into the warm air flow, so you have to look into it. Plus, if you leave it, the whole boat will start to smell like it. I guess you have checked that the wind is not blowing the exhaust fumes back into the air inlet area.

Hopefully nothing has hidden and died in the tubes.
 
I have looked fairly carefully into the possibility of exhaust fumes, but I don't think this is the cause, because the exhaust is over the stern and the heater is in a locker some 8 feet or so away. And even with the locker lid open and lots of cold fresh air going in today, the hot air coming into the cabin smells like warmed up plastic! So I am fairly sure the plastic piping is the cause - the question is how to overcome it, or at least improve things a bit. It has been the same since new, and I rather hoped things would gradually improve, but it seems much the same as 4 years ago.
 
I'm surprised plastic has been used. Mine are a sort of cardboard insulated corrugated aluminium tube. Maybe the ducting needs replacing to remove the odour.
 
I agree, mine used to be corrugated aluminium tube.
Plastic sounds very dodgy as the temp at the heater end of the warm air feed will probably be high enough to melt plastic!!!
Get it seen to quickly or it could be a fire hazard.
 
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sounds more like the the tubing they use on cars, not designed to cope with that much heat without the smell leeching out from the plastic. car heater matrix must be 25-20 degrees cooler than the output on a diesel heater.

steve
 
Mmmmmm! Thanks for the comments on ducting - I will take another close look when I am next down on the boat. The whole assembly was fitted from new (by a boatbuilder who has since gone bust!), and it all looks kosher, at least to my untrained eye, with the sort of Y pieces, vents etc as shown on the Mikuni website. However the picture of the ducting shown on the website indicates that the inside of the tubing is a silver colour (suggesting foil), but I am pretty sure mine is black! I wonder if Mikuni have changed the spec? I will take another look and then give them a call.
 
My Mikuni does exactly the same as yours on the same boat as yours, Did it from new and the smell that I thought was dieselly goes after about 30 minutes and even quicker if the heating is used a lot. The tubing in my opinion is fine as it is the tubing designed for the heating. I always thought it was just some excess diesel burning off at start up but couldn't figure out how the fumes get from the combustion side to the blown air side.
 
Slipperman said:
I have a Mikuni MY16 heater, with 2 outlets. I don't use it that much, but after 4 years ownership I find that though the heater chucks out warm air efficiently, it has a smell to it. It isn't a dieselly or fumey smell (that would obviously be dangerous), but is, I think, the smell of the plastic tubing. I have tried running the heater at full temperature for a couple of hours at a time, but after several attempts I can't say it is noticeably less smelly. I can more or less put up with it, but my other half objects strongly! Any ideas? I did wonder, for instance, if I could fit an air freshener type cartridge (like you sometimes see in cars) next to the outlet? Any other ideas?
Click to expand...

I've had exactly this same problem, I wonder if you will find the same cause?
My heater is right on the transom inside the aft locker, there is quite a long run of ducting it wasnt very well supported and had a tendency to droop.
This droop caused the hot air pipe to split where it went through a bulkhead letting very hot air escape into the cockpit locker. Above the hot air leak my bilge pump pipes ran, as the pipes got hot, they softened and also drooped, soon the plastic bilge pump pipes were laying on the hot air pipe and they started scorching and that was what caused the plastic smell.
 
Thanks for the further comments. I have been down to the boat this morning and taken a careful look at the ducting. I took the outlet vent off so that I could see the inside of the tube - it is definitely not foil! It consists of spiral wound wire on the inside, and the body of the tube is made of a black plasticky rubbery substance, exactly what I am not sure. But I am fairly sure this is what is causing the smell - it has never smelled of diesel or exhaust fumes, and there are no splits in the tube or other pipes interferring with it.

I am fairly sure that what I have is what was provided in the kit which came from Mikuni. However, since Mikuni made their name supplying heaters for lorries, I wonder if the tubing used 4 years ago was as for a lorry, but that now they have a different version for boats (maybe in response to complaints!) - certainly what is shown on their current website looks different what I have on the boat. I will give them a call after Easter.
 
Mikuni, same problem here - after 8 years, any solutions? When I turn on the heating, the entire boat smells like being in the middle of the engine room... I'll try to get a hose to play with the air inlet, which is my first suspect.
 
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My Mikuni had the same smell but after a long time it did stop producing it. I am sure it is a product of the heat on the rubbery air hose supplied with the kit. Apparently this type of hose has very good heat insulation properties. My Mikuni has been in service for over 8 years now and otherwise has been trouble free.
 
CJU said:
My Mikuni had the same smell but after a long time it did stop producing it. I am sure it is a product of the heat on the rubbery air hose supplied with the kit. Apparently this type of hose has very good heat insulation properties. My Mikuni has been in service for over 8 years now and otherwise has been trouble free.
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Right, I'll try to run if for a day and see if it stops pushing out that aerosol.
 
My apologies, I started this thread but did not report the end result - which was that I went back to Mikuni and, as I suspected, they had changed the tubing from the old rubbery stuff to foil. I bought the required length and fitted it, and it has indeed been much better.
 
Slipperman said:
My apologies, I started this thread but did not report the end result - which was that I went back to Mikuni and, as I suspected, they had changed the tubing from the old rubbery stuff to foil. I bought the required length and fitted it, and it has indeed been much better.
Click to expand...

Thinking on the Eberspacher tubing, I hope it is the right size and fits well. Silly me, forgot to measure the diameters before I left the boat, however it seems all Mikunis use 80mm tubes...

Have you replaced the Y-branches as well?
 
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RAI said:
I'm surprised plastic has been used. Mine are a sort of cardboard insulated corrugated aluminium tube. Maybe the ducting needs replacing to remove the odour.
Click to expand...

This seems like the tubing that came with my Propex gas heater. Most plastics seem to smell when heated up and if the plastic extractor ducting type has been used I don't think that this is really designed for heat.
 
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