Eberspacher heater exhaust gets so hot

[tigr]

Hi, I had a question from a member of our club, they have agreed for me to ask the experts on the forum
"Our Eberspacher heater exhaust gets so hot you are unable to touch it. An engineer has put a camera down and cannot see any crack in the pipe. It is not used often but this last time the plastic over pipe got so hot after one hour it was smelling. The heater is operating fine. The Bosun's locker has been excessively damp and we wonder whether condensation has formed in the pipe causing this issue.
Does anyone have a suggestion please?"
Hope you can help and thanks in advance

 

[chasroberts]

Not sure it's any help but my Eberspacher has an 'asbestos' type cover, obviously intended to cope with high temperatures. Exhaust gas temperature must be high so wonder why you have a 'plastic over pipe'. If it is indeed plastic would think it is possibly the wrong sort of insulation? Just a wild stab in the dark. Do you have a way of measuring the actual gas temperature and then comparing it with Eberspacher spec.?

Good luck

Chas

 

[sailorman]

the exhaust on a offshore wind boat caused it to burnt up in 20 minutes a month ago, the unlagged exhaust passed through a plywood bulkhead

 

[rob2]

Agreed, you shouldn't consider a plastic cover unless there is substantial insulation between them. After all, it is really no different from the exhaust pipe on your car and that benefits greatly from being outside in the airflow of a fast moving vehicle! You still wouldn't expect to touch it without getting hurt.

It could be that damp has got into any insulation and is rendering it useless, but that should resolve itself as it dries in the heat - but you'll get the plastic too hot in the process and it will prevent rapid drying anyway.

Rob.

 

[Steve Clayton]

"plastic overpipe" doesn't sound right to me. Should be a sleeve of heat resistant cloth-like material; loads on ebay; and yes it gets too hot to touch.

 

[David2452]

Plastic is a very definite no no, if the insulation was damp or contaminated I promise you would know about it as there would be steam and or smoke an smell. The best currently available exhaust insulation is this stuff, you can hold the outside even after the heater has been running for hours and it is water repellant http://www.mikuniheating.com/Details.cfm?ProdID=518 As for the reason for the exhaust getting hot, did the "engineer" check the CO2 level and gas temperature in the exhaust to see if it was running a bit lean?
Are you sure the outer sleeve is plastic and not APK ducting, Eber often use that, a bad idea in my mind as it makes inspecting for leaks very difficult.

 

[tigr]

So from what I can see so far is that the exhaust does get too hot to touch and that is normal.
If it is believed to be hotter than normal then to get an engineer to check the CO2 & gas temperatures.
Also that the exhaust should be lagged.

Does that sum up?

 

[lynall]

See lots of them at work on trucks and I for one certainly wouldnt attempt to touch it whilst running, maybe just as its fires to confirm its actually burning, but thats it.
Our boat one is lagged as mentioned above

 

[David2452]

So from what I can see so far is that the exhaust does get too hot to touch and that is normal.
If it is believed to be hotter than normal then to get an engineer to check the CO2 & gas temperatures.
Also that the exhaust should be lagged.

Does that sum up?

An acurate precis.