exhaust condensation

[veggie]

Hi all,

I just finished piping my Listeroid exhaust through a wall thimble to the exterior of my garage.
Inside the garage there is a steady downward slope to help move  condensation away.
On the outside of the wall the exhaust turns vertical for 1ft. with a rain cap flapper.
Questions:
By going vertical I think I may have created a water trap 
How does condensation exit a vertical exhaust system?
Should I drill a small hole on the underside of the elbow where the pipe goes vertical or is there not enough condensation to worry about?

Thanks,
Veggie

[carbon-rod]

Maybe you could put a small ball valve at the lowest point in the exhaust and every so often just open it and let any excess water out of there....Once the exhaust is up to temperature it might just boil out all the water that is in there, as long as you don't get too much in there to overcome the downward slope the only problem you will be facing is your exhaust rusting out over time I guess.

[dieselgman]

Use a tee at the lowest point elbow and run a small vertical drain pipe down below that point to allow any liquid water to escape harmlessly. Under normal circumstances your exhaust should be non-condensing, that is its temperature will be above the dew point or condensing point of the water vapor. If run cold, that dynamic will change, so be sure to make your operational times long enough for the entire system to become hot.

dieselgman

[quinnf]

In order to eliminate condensation you need to insulate the exhaust line and muffler.  Consider wrapping it with fiberglass, held in place with fiberglass tape.  One upon a time they used asbestos batting and tape for the task but . . .

Idear is to encase the exhaust line and muffler with a blanket of some noncombustable material, and fiberglass is the cheapest and most available insulator.

[Tom Reed]

I'll go with the small hole. My muffler guy does that and says the mufflers will last a lot longer before rusting out. The mufflers in my Scout were installed about 12 years ago and they're still in good shape. Making a drip leg with with a tee and a small hole in a cap will work well.