PVC roof power vent options

[Vietjdmboi]

I am planning to install a navien npe-180a2 but wanted to see what options I have for the pvc vent. Plan is to do a power vent. Intake air will drawn in from the garage and vented going straight up out the roof.

Currently there is a 4” asbestos flue which I want to remove. The roof flashing is for a 4” diameter pipe obviously. I found a 3” direct vent with a 4” diameter body but don’t need the intake side. Is there any other options or would using the 3” concentric vent be my best option?

thanks!

 

[Fitter30]

You don't need a concentrate roof vent your not running combustion air. If the asbestos flue is straight can run 2" pvc up to 75'. A 90° ell = 8' you will use 2- 90°
on the roof flash around the 2" to cover the.asbestos pipe.

 

[Sponsor]

 

[Vietjdmboi]

Here is an image from the roof side. Flue is about 3 ft long and straight.

 

[GReynolds929]

Why not replace the existing flashing with a new 2" flashing?

 

[Fitter30]

I'm surprised you didn't have draft problems as low as the flue is from height of the peak with a natural draft water heater or furnace.

 

[Vietjdmboi]

"Why not replace the existing flashing with a new 2" flashing?"

Im not against this. Just wanted to see what options were available with the current flashing