Venting problem

Snowmelt

Came across a 400,000 btu steam boiler that is vented on side of building, roughly 10 feet in building. Then goes out side of building . Strait up 20 feet. It’s all 10 inch venting….. it’s getting condensation, I know it’s a long shot but anyway I can install a condensation tee on the vertical b vent outside or is that illegal?

hot_rod

Standard B vent outside? If so it is condensing because it is too cold, that condensate  eat through the inner tube of the vent.  Unless it is stainless it cannot handle condensation

Is it sized properly?

Snowmelt

I’m going there one day during the week …….. that’s the best I can do

EBEBRATT-Ed

you can't put a drain outside with a trap it will freeze. B vent can be bought with a stainless or aluminum liner.

I would check the stack temp make sure the boiler is firing up to rate. Maybe insulating the 10' inside would help especially if it is in a cold area