For reasons unrelated to the oll heater, Id like to move its chimney from venting thru the roof to going out the side of the garage wall. This will involve making the pipe longer and much of that increase will involve the pipe traveling horizontal.

I know that i will need to readjust the barometric damper afterwards.

Any other concerns or things that i should know?

the original bryant install paperwork gives no info on exhaust. I asked them and they said that

I need to ask my authorized dealer.

The original beckett paper work actually gives more info. Like 1/4" rise for every 12", might need an exhaust fan to pull the exhaust out, if exhausting to out side of building, it's better to have the combustion air intake going thru the same wall to balance the unit. that last one I really dont understand and would rather leave the intake in the garage.

How would that exhaust fan effect setting the damper?

what else?