It's pretty simple. Short run of 3" pipe from one soffit vent to the intake of the Combi boiler.

Then a run of about 28' of 3" pipe to the other side of the garage and out the soffit vent for the exhaust.

Intake is on the north side of garage and exhaust is on the south. I could put both vents on the same side with some spacing between them, but it works out much better for my situation to vent to each side of the garage.

Boiler has a built in fan for power vent and has a maximum pipe length of 100'.

Trust me, I've read the manual for the boiler and evaluated the venting requirements. There is more than sufficient venting. 2" pipe is actually sufficient up to about 50' if I recall correctly.

This boiler can use a concentric vent thru the wall and other options. My plan is within the necessary requirements.

I understand that not all natural gas or propane boilers or appliances have the power vent, however, this boiler is set up for method.

I'm not poking a vent pipe thru my standing seam roof. I would go thru the brick wall before I did that.

More details and pics to follow as this progresses...