Fuel burning heater smoke

[usmc81301]

I have a fuel burning heater and I thought I had an exhaust leak because I had smoke in the cab. I pulled it apart and sealed all of the exhaust. I then noticed that it was blowing smoke out of the air tube. It does stop after about 30-40 seconds. My question is, is this normal or do I have a problem?

 

[cranetruck]

There should never be smoke in the fresh (hot) air stream. If it occurs, then the combustion chamber seal is faulty.
The Benmar heater seal is prone to leak, being made of a fiberglass material, but the SW heater uses a silicone rubber O-ring and is located in a cooler part of the chamber and is less likely to leak.
If you have the SW heater and the smoke goes away after a while, then there may have been a temporary overpressure due to residual fuel burning off in the beginning causing the O-ring to give.

Which heater do you have?
Have you had false starts or shortened shut-downs (should last up to 3 minutes) and possibly ended up with left-over fuel in the combustion chamber?

 

[PeterD]

There was a good writeup on these heaters in the last MV magazine, too...

 

[Stalwart]

There was a good writeup on these heaters in the last MV magazine, too...

Yes, and it was written by Bjorn, AKA Cranetruck, who posted above you.

 

[usmc81301]

The heater is a SW. I have not had any starting problem. It takes about 1 minute to get going and runs fine.

 

[usmc81301]

Where can you buy the o rings for these?

 

[cranetruck]

First take the heater apart and clean the seal. If it can't be reused, the Stewart Warner unit uses a silicone O-ring that should be an off-the shelf item (McMasters ?). I'm still experimenting with the Benmar seal, which is a high temperature type, possibly fiberglass...

 

[usmc81301]

Thanks for the info.