Venting question (Heat loss)

[youbaxter]

I just recently purchased a Beacon-Morris garage heater (75k). This particular model is around 80% efficient.

My question is, how 'hot' is the air which is vented outside? Reason I ask, is I'm thinking of venting vertically and concerned w/ discoloring of my garage wall and soffit from heat release.

FYI, venting about 36 inches under soffit and thinking extending it 8-10 inches (type-b)

 

[BoilermakerNate]

I would say the flue gas is somewhere around 250°F, probably not too much hotter than that. And if you are using double wall B-vent for your venting, the surface temperature of the vent right next to the heater should be less than 200°F. The flue off my heater is probably 12" to 18" from the wall and ceiling in my garage and I've had no problems. Just make sure you use a fire ring for the vent penetration through the wall/ceiling and that you maintain the minimum manufacturer recommended clearances for the heater and you should have no problem.