Eberspacher fumes

[Lucky38]

Hi, know Eberspacher questions can get people hot under the collar, but I couldn't find an answer to our problem in Search.
Basically the hot air pumped into the cabin smells of fuel. I thought it was probably a leak in the exhaust in the lazarette where the pump lives. Fixed a crack near the exhaust outlet, but problem's still there.
Is there likely to be another leak in the exhaust system or could there be another problem? Could it be down to the pump itself - it's not been serviced for a long time...
Many thanks

 

[snooks]

If it's a smokey diesel exhaust smell, a lot of the time this is a bit of diesel or grime on the lagging of the exhaust, this burns off making the smell which it promptly sucked in through the air inlet and pumped into your cabin.

The best thing to do is leave the heating on as hot as possible for quite a few hours. We went for a sailing and even though it was a hot spring day we had the heating on for 5 hours....never had the problem again.

Alternatively extend the air inlet pipe to a vent outside

Apparently it happens more in spring time when the lagging collects moisture and grime over the winter clear out.

 

[fireball]

A few options ...

1st - ours gets the heating air source from inside the cabin rather than around the unit itself - this (should) prevents the musty smell in the locker from entering the cabin. It also ensures a clean warm-air source. Alternatively as Snooks suggests - vent it in from outside.

I've just serviced ours as we had some burn problems (gauze - fixed!) - but also, more worryingly we had an exhaust leak - which I noticed because there was smoke coming out around the outer cover - but not from the joint between exhaust outlet and pipe... Probably noticed it because it wasn't burning properly - hence the smokey exhaust...

This was down to the gasket between the two halves of the unit hadn't sealed properly and was letting the exhaust gasses through - as the warm air passes around the outside of the unit it was picking up some of these gasses and putting them through the heating system into the cabin ...

We've now got all that fixed - however, on testing the cockpit tent filled with exhaust gasses once again - but this was because there was a wind up the stern of the boat where the exhaust is - fortunately we have a bit of exhaust pipe that we can slot over the skin fitting and pipe it to the side where it's blown away....

 

[David2452]

As A Webasto and Mikuni agent I see this quite often on self installs and it is often simply that people did not have access to or did not follow the specific marine installation instructions. The usual cause is that the cabin heating air is taken from an area where the exhaust runs, often the same locker space as the furnace itself, or that the simple anual service procedure which includes a check on the integrity of the exhaust has never been done. A leak where the exhaust tube joins the stub is often present even on new installs because no exhaust sealing paste was used, hose clips used to secure it etc. etc.. This is a complete no no. When installing in a motorhome or truck the exhaust and combustion air intake are on the outside of the vehicle and sealed by using a silicone gasket on the furnace base so the exhaust sealent is never mentioned or indeed used, but on a boat it is essential to my mind. Oh, and whilst I'm at it, those vehicle type silencers often seen on fleabay are not gas tight and were never intended to be used inside a vehicle or boat. Another, much rarer cause is heat exhanger failure, they have a recommended service life of ten years, I know there are thousands of units that have been in use well in exess of that but the can sometimes distort, corrode or crack. Stuff works until it breaks.

 

[Talbot]

I installed a unit in my last boat. I chose that the combustion air came from inside the boat, but the air to be heated and circulated inside the boat was brought in from outside. This ensured that I circulated air into the boat, thus helping to reduce the condensation problem. Once I had really run the system hot for a few hours, the smell was below notice threshold.

 

[David2452]

Technically you should not draw the combustion air from living spaces as it depletes oxygen levels, but I guess as the heated air is from outside in the fresh air then it's replacing it at a fast enough rate anyway.

 

[Talulah]

Technically you should not draw the combustion air from living spaces as it depletes oxygen levels, but I guess as the heated air is from outside in the fresh air then it's replacing it at a fast enough rate anyway.

What? How can drawing the combustion air from living spaces deplete Oxygen levels?

 

[lenseman]

Regardless as to whether their should be smokey smells from your heater, it matters not a wit, GET A Carbon Monoxide detector for your own peace of mind!

Do it.

http://www.diy.com/diy/jsp/bq/nav.jsp?action=detail&fh_secondid=11117870&fh_location=//catalog01/en_GB/categories%3C{9372015}/categories%3C{9372044}/categories%3C{9382012}/specificationsProductType=fire___gas_safety/specificationsSpecificProductType=carbon_monoxide_detectors

 

[Talbot]

Technically you should not draw the combustion air from living spaces as it depletes oxygen levels, but I guess as the heated air is from outside in the fresh air then it's replacing it at a fast enough rate anyway.

My new system is a water heated with mini radiators which makes it easier to fit and eradicates a number of these problems.

 

[Talulah]

That is 100% wrong.

However, if you draw the air to be heated from inside, then you are merely recycling the air to be heated - possibly more efficient from a heating viewpoint, but if (and that is a big if) if your boat is sealed tight, you then reduce the oxygen levels inside the boat. What normally happens in these circumstances is that the boat is not 100% sealed so cold outside air leaks in.

If you draw this heating air from outside, you are ensuring a decent replacement of oxyginated air, and it is heated air that leaks through those gaps to the outside.

+1
It is sometimes worth having a choice of drawing the heating air from outside or inside.
In really cold conditions when drawing outside air the Diesel Heater may not be able to raise the temperature high enough to make life comfortable inside.

 

[David2452]

What? How can drawing the combustion air from living spaces deplete Oxygen levels?

Because it sucks in cabin air, uses the oxygen in it and chucks the rest out of the exhaust.
Not such an issue with a well ventilated cabin or where the heater draws the heated air from outside but with recirculated air or radiators and a wet system it can become an issue.

 

[David2452]

Regardless as to whether their should be smokey smells from your heater, it matters not a wit, GET A Carbon Monoxide detector for your own peace of mind!

Do it.


+1

 

[Talulah]

Because it sucks in cabin air, uses the oxygen in it and chucks the rest out of the exhaust.
Not such an issue with a well ventilated cabin or where the heater draws the heated air from outside but with recirculated air it can become an issue.

Now you're worrying me. You're a heating engineer.
The exhaust is not recirculated into the cabin. Cough splutter.
I'll put it down to you having a seniour moment.

 

[David2452]

Now you're worrying me. You're a heating engineer.
The exhaust is not recirculated into the cabin. Cough splutter.
I'll put it down to you having a seniour moment.

No, no, it's not the exhaust fumes from the exhaust but the fact that air is being removed from the cabin to fuel the furnace and not being replaced that would be the issue.
Not unlike breathing in an unventilated room reducing oxygen levels only on a bigger scale.

 

[Talulah]

No, no, it's not the exhaust fumes from the exhaust but the fact that air is being removed from the cabin to fuel the furnace and not being replaced that would be the issue.
Not unlike breathing in an unventilated room reducing oxygen levels only on a bigger scale.

Air is being removed at the same concentration rates of Nitrogen/Oxygen.
The air expelled has less Oxygen in it but the modified mixture goes out the exhaust.
Only if the heater filtered out the Oxygen from the air could it reduce the Oxygen levels in the room and it doesn't have an Oxygen filter.
Unlike breathing in a room where the exhast gases (breath) contains less Oxygen and is mixed back into the room.

If the room was sealed the heater would in effect cause a vacuum in the room whilst maintaining the same ratios of oxygen/nitrogen. (Obviously the heater is not powerful enough to create a vacuum and the room leaks enough to keep the pressure constant.)

 

[Scotty_Tradewind]

If it's a smokey diesel exhaust smell, a lot of the time this is a bit of diesel or grime on the lagging of the exhaust, this burns off making the smell which it promptly sucked in through the air inlet and pumped into your cabin.

The best thing to do is leave the heating on as hot as possible for quite a few hours. We went for a sailing and even though it was a hot spring day we had the heating on for 5 hours....never had the problem again.

Alternatively extend the air inlet pipe to a vent outside

Apparently it happens more in spring time when the lagging collects moisture and grime over the winter clear out.

I had similar after I had mine serviced. The exhaust has an insulated covering that had got diesel soaked on it. I couldn't stand the smell so I stripped off the insulation and renewed.
No more smell afet a few minutes.

However, the OP said the smell was coming via the warm air outlets in the boat so not quite the same as my problem.
Obviously there is some unburnt diesel contamination from the pumped diesel side to the heat outlet side. Could it be a gasket not sealing or another crack?

 

[theoldsalt]

Talulah,

Exactly correct.

 

[David2452]

if the room was sealed the heater would in effect cause a vacuum in the room whilst maintaining the same ratios of oxygen/nitrogen. (Obviously the heater is not powerful enough to create a vacuum and the room leaks enough to keep the pressure constant.)

Obviously in theory that is the case and I'm not saying it will suffocate you but from practical experience when air is drawn from inside living space as opposed to fresh air the heaters do burn richer due to warmer less oxygen rich (by volume) air and that brings us around to coking up again. There is no valid reason not to give the things the best chance of working properly and that is managed very simply by installing them as per manufacturers specs.

 

[Talulah]

Obviously in theory that is the case and I'm not saying it will suffocate you but from practical experience when air is drawn from inside living space as opposed to fresh air the heaters do burn richer due to warmer less oxygen rich (by volume) air and that brings us around to coking up again.

That makes sense. Draw the combustion air from outside whilst the heating air may come from inside or outside (refer to above). The colder air will cause the fuel to burn better due to Air Mass Flow rates.
There is one caveat. Assuming the heater itself is in a confined space (i.e. cockpit locker, in the stern etc) the combustion air is sometimes drawn off from the same location. This provides for some throughput of air in that space where otherwise there may be inadequate ventilation.
Hence an indirect benefit.

 

[Mistroma]

Fuel Smell from heater

I did find one other reason for a smell of fuel from the heater. I had a D3L on my previous boat for for around 20 years and after 15 years use it developed a smell of diesel when running.

The problem appeared at the start of the season and was diagnosed by running the heater with the hot air outlet disconnected. It was nice and cosy in that locker with no smell at all. Strong smell of fuel when the ducting was connected up again. The paper lining of the ducting had wicked up a small amount of fuel and this was causing the problem. I found the kraft paper lining was damp throughout a 3m run of the ducting hose.

Turned out that a fuel leak developed on the engine during a cruise the previous year. I reduced it to the odd drip and most of that evaporated when hot so I was able to leave it until the autumn. I craned out very early that year and used the D3L very little at the end of the season.

But (always a but), I didn't notice that the drip found its way to the heater ducting. It wasn't reaching the bilges so the leak didn't seem to be a major problem. However, the heater ducting was acting as a wick and absorbing some of the diesel before it evaporated.