Chinese heater exhaust 'insulation smoking'

[jamie N]

Of course, it could be any diesel heater, but the issue that I had was where the exhaust pipe does become extremely hot during operation, it's wise to insulate it in order to prevent damage to perhaps the hull, or gear in the locker that it maybe passes through, whatever.
I used a fairly standard exhaust wrap, one of dozens available, and duly wrapped the pipe, paying particular attention to where it passes through a bulkhead, and up through the stern locker to the actual exhaust fitting on the transom. The heater unit is in the engine bay of my GK24, where there's actually no engine, as I'm an outboard variant. This bay is accessed from the cabin, which is where the fresh air to be heated is also positioned, because the alternative's not feasible.
Anyway, it is mentioned that the wrap stuff will seem to smoke a bit as the chemicals burn off, it's also known that they do attract condensation and will steam as they dry out when the heater's on, so I persevered with it for about 30 hours running, and still had a 'smoky' cabin, which is the problem. The smoke is largely steam, but also still the stuff from the wrap. I do have a gas/particulate meter, and it reads as everything being OK, but it's not right, so I changed the wrap out for straightforward aluminium wrap, which seems to be a far better solution for me, albeit after only an hour of running. If I'm the only one who's suffered this, oh well, but it might help others.

 

[PaulRainbow]

I'd use exhaust lagging sleeve, such as this (other suppliers are available).

EXHAUST LAGGING SLEEVE 36mm to 38mm

 

[PetiteFleur]

I used tradional exhaust lagging wound around the exhaust pipe, secured each end with stainless jubilee clips. They get warm but you can hold it without getting burnt. Works for me, heater at the rear with only a distance of under 3ft to the outlet on the stern.

 

[wallacebob]

My exhaust lagging sleeve “smoked” for an hour or so when new. It is good quality stuff, from UK supplier. It may also have been the flexi exhaust pipe, burning off a coating? Again from good UK supplier . After that no issues after year of use.

 

[Chiara’s slave]

We recently replaced ours with a Planar exhaust and skin fitting. A slight smell at first start up, but it's all good now. It also seems to have improved performance generally.

 

[jamie N]

It would seem that the main problem is that I fitted sub-standard material. I've had a look to ID which site I bought it from, but can't find it.
After such a short time of running with the 'new' ally wrap, I'm happy enough, but would've (probably) fitted the sock that Paul recommends as well, but the idea of breaking the seal at the exhaust manifold to slide the sock on doesn't fill me with joy, such is its importance!
Cheers to all.

 

[LittleSister]

. . . the issue that I had was where the exhaust pipe does become extremely hot during operation, it's wise to insulate it in order to prevent damage to perhaps the hull, or gear in the locker that it maybe passes through, whatever.
I used a fairly standard exhaust wrap, one of dozens available, and duly wrapped the pipe, paying particular attention to where it passes through a bulkhead, and up through the stern locker to the actual exhaust fitting on the transom. . .

It seems to me that what you have bought will not insulate the pipe - aluminium will conduct heat - but is the type that might be used only to shield it - i.e. keep anything from getting close enough to it to touch it.

Quite where the smoke is coming from I don't know, but could be some coating or manufacturing residues burning off the pipe as mentioned, or perhaps even the bulkhead or something else burning if the heat is being conducted to it by the aluminium shield mesh that might also be touching the pipe.

 

[jamie N]

It seems to me that what you have bought will not insulate the pipe - aluminium will conduct heat - but is the type that might be used only to shield it - i.e. keep anything from getting close enough to it to touch it.

Quite where the smoke is coming from I don't know, but could be some coating or manufacturing residues burning off the pipe as mentioned, or perhaps even the bulkhead or something else burning if the heat is being conducted to it by the aluminium shield mesh that might also be touching the pipe.

Yup, the aluminium sheet will simply diffuse the heat, and also contain the highest contact points. I was feeling along the ally sheet yesterday, and it wasn't ever untouchable.
Where the exhaust goes through the bulkhead is well protected, and there's no evidence of scorching at all.
The coating on the wrap should've burnt off by now, which is why I believe that I bought a wrap of crap.
The same wrap also seemed to conduct moisture, which took time to steam off, and did present moisture to the area.
Today I'm going to take a laser/infrared thermometer and see what the real temps are.
All of this illustrates the retired life of a highlands yottie......

 

[ylop]

I'm surprised that you got enough moisture in it to steam for more than a few seconds unless it was sitting in a puddle or has a leak feeding into it? My observation is that the first 6" or so of the exhaust can get VERY hot quickly, but after that take some time to heat up - during which any water in the insulation would evaporate off slowly (invisibly). After an hour or so I'd expect the wrap to be "bone dry", and take a long time to "soak up" enough moisture to steam again? If it is "wet" then it might stop is getting hot enough to burn off whatever needs burned off? Is it definitely the insulation? I've seen reports that the rubber gasket on the cheapest heaters can be smoky for a very long time.

 

[wingcommander]

Yup, the aluminium sheet will simply diffuse the heat, and also contain the highest contact points. I was feeling along the ally sheet yesterday, and it wasn't ever untouchable.
Where the exhaust goes through the bulkhead is well protected, and there's no evidence of scorching at all.
The coating on the wrap should've burnt off by now, which is why I believe that I bought a wrap of crap.
The same wrap also seemed to conduct moisture, which took time to steam off, and did present moisture to the area.
Today I'm going to take a laser/infrared thermometer and see what the real temps are.
All of this illustrates the retired life of a highlands yottie......

Your laser temperature readings will not be accurate, due to highly reflective surface . If you want an accurate reading, paint it matt black . Heat resistant paint recommended lol

 

[PaulRainbow]

It would seem that the main problem is that I fitted sub-standard material. I've had a look to ID which site I bought it from, but can't find it.
After such a short time of running with the 'new' ally wrap, I'm happy enough, but would've (probably) fitted the sock that Paul recommends as well, but the idea of breaking the seal at the exhaust manifold to slide the sock on doesn't fill me with joy, such is its importance!
Cheers to all.

You can wrap the aluminium shield, without taking it apart, by using some of this, other sellers available (without the marine tax)

Exhaust Lagging Glass Tape

 

[jamie N]

In fact that's very similar looking to the stuff I've got!
No, I'm not convinced that I've done a good enough job on this heater anyway, so for all of the time it'll take, albeit a real PITA for access, I'll remove the exhaust, and then proceed, probably with the aforementioned sleeve.
Cheers.