Another Eber question

[stone beach]

I have an Eber diesel fired water heater, first time I have had one of these.
The exhaust is an inner stainless semi flexible inner duct with a more flexible outer black aluminium duct cover, there is insulation/lagging between the two. It looks like it a supplied product not a home made assembly. I don't see a silencer anywhere and have read this might be incorporated in this assembly.
Anyone know what temperature the outer cladding should run at with the burner going full on.
I have tried to take readings with an IR gun, but of course it is hard to get to.
The inner portion reading is around 200 deg, which seems too low, however there is only a small amount of the inner duct visible where it is clamped over the heater outlet and I don't think I am getting a proper reading. The outer cover is around 100 degrees at the outer end and about 130 close to the heater, which seems high. This is encased within a plywood box where it passes through the accommodation. Before I get too far into it I would like to know how those temperature readings compare to others.

I don't think there is an exhaust leak as no smell of fumes or any sign of smoke, I suspect the lagging might have got wet at some stage and therefore is conducting heat, of course if that is the case and I keep the heater running it could dry out and the outer temperature should then fall.

Comments please.

 

[mikegunn]

You are describing a typical Eberspacher exhaust installation. The silencer is sometimes omitted and if you can’t see one I doubt you have one. There are two designs currently in use. A quick google will depict them. An exhaust silencer doesn’t make a huge difference to the perceived noise level inside a boat but does attenuate the noise from the heater’s exhaust significantly. Always appreciated by neighbouring boat crews.
I’ve never checked the exhaust system temperatures on any that I’ve had fitted and am wondering why you are concerned. Having said that, the temperatures that you have recorded don’t seem to be excessively high or low.
Mike

 

[stone beach]

You are describing a typical Eberspacher exhaust installation. The silencer is sometimes omitted and if you can’t see one I doubt you have one. There are two designs currently in use. A quick google will depict them. An exhaust silencer doesn’t make a huge difference to the perceived noise level inside a boat but does attenuate the noise from the heater’s exhaust significantly. Always appreciated by neighbouring boat crews.
I’ve never checked the exhaust system temperatures on any that I’ve had fitted and am wondering why you are concerned. Having said that, the temperatures that you have recorded don’t seem to be excessively high or low.
Mike

The outer cover is around 100 degrees at the outer end and about 130 close to the heater, which seems high to me. Trying to get a clue if it is in the normal range for these units

 

[B27]

One key thing is that the exhaust gases must not condense as the exhaust pipe is sealed within the boat, so they generally fun pretty hot.

The outer of the lagged exhaust will get pretty hot if there's not much free air around it.