Installing an all in one diesel heater, how to seal exhaust?

[Vannautical engineer]

I'm going to be helping someone install one of the Chinese diesel heaters that comes as an all in one unit into a van. (The diesel tank and the unit are in one metal enclosure.) Since the unit itself will be raised up off of the floor somewhat, I'm not quite sure what kind of sealant to use to seal where the exhaust pipe will go through the floor. Would some kind of high temp silicone work? That exhaust pipe from the heater gets pretty hot. Thanks.

 

[abnorm]

Caulking implies the hole would be a close fit to the pipe ?

I like a little gap in this situation......Too much heat transfer....just like a wood stove

stuff the gap with a Mineral Wool insulation

 

[Vannautical engineer]

Yeah, not a bad idea, but then I wonder about:

1) Would the insulation seal well enough to keep out any fumes from the exhaust?

2) How do you keep the insulation in place and keep it from getting wet from road spray?

 

[LoupGarou]

It’s not recommended to use the all in one units in vehicle applications. The heater body needs to be mounted flat to the floor so the exhaust connection is outside the vehicle

 

[hugemoth]

Many people use the all in one heaters in a vehicle. The main thing is to route the exhaust pipe so the exhaust comes out to the side or back of the vehicle, not underneath where it can rise up and enter the vehicle through any holes. Fiberglass packing used for sealing wood stoves works for sealing any gaps in the floor. Always keep a CO alarm in the vehicle with any heater or stove.

BTW The all in one units have the standard heater inside which can be removed and mounted direct to the floor if desired.

 

[PlethoraOfGuns]

I used carbon felt to seal around my exhaust pipe. But I'm sure you could use high temperature caulk.

 

[wb8vyn]

I'm going to be helping someone install one of the Chinese diesel heaters that comes as an all in one unit into a van. (The diesel tank and the unit are in one metal enclosure.) Since the unit itself will be raised up off of the floor somewhat, I'm not quite sure what kind of sealant to use to seal where the exhaust pipe will go through the floor. Would some kind of high temp silicone work? That exhaust pipe from the heater gets pretty hot. Thanks.

I've used diesel heaters for many years, sitting on one right now.
Exhaust tube does get very hot. Best to not use any sealant. Reason why is that the exhaust will expand and contract as it heats and cools. Best idea would be to make a metal flange with ears that fit the exhaust tube and allow for movement. Be sure to clear any combustibles both inside and out for 3 or 4 inches around.
As an aside, Diesel fuel is smelly, Spills will happen when re-fueling. Also the "all in one" units can be noisy. be sure to isolate both the dosing pump and all lines leading too and from to help the thumping noise. Do not replace the fuel lines with flexible hose to quiet it down. Nylon stiff discharge line from dosing pump is mandatory. Suction line not so much. The pump and it's discharge line are in effect an injector. pressure must be maintained throughout.

 

[maki2]

These issues have long ago been solved in the marine diesel heater installations. So no need to invent stuff. You can purchase ready made solutions.

You can purchase a diesel heater "thru hull exhaust port", use an image search to see them and find a purchase source.

If the tube is too hot on the interior you can purchase woven "fiberglass tube sleeving" material to put over the exhaust hose. That will insulate the exterior of the exhaust tube so that it does not create any issues of heat against nearby surfaces.

I created a gasket seal to put under the exterior surface of my exhaust port by cutting it from a, smooth surface, inexpensive "silicone place mat". That silicone sheet material withstands about 400 degees of heat, waterproof, long lasting, inexpensive. Easy to cut with scissors. You can find them on Amazon, sometimes I see them at Goodwill stores.