Mod Con boiler catergory 4 venting though roof

[t2]

I have a customer who would like there Lochnivar Knight boiler cvpc vent pipe changed from a side sill plate vent to a up though the roof vertical vent.
The snow line is a problem even though the vent and intake go up 2 feet from the sillplate. There is a bedroom closet 10 feet to the left of the boiler.
I was thinking of framining in a chase in the corner of the closet and going up though it and out the side at around 8 feet or up though the attic to roof. Lochnivar wants cpvc used for any closet or alcove install. cpvc is rated at a higher temp then pvc but i cant find a section in the fuel gas codebook on plastic venting up though the house. What does everyone think .

[hvac64]

We go by manufactures specs. Always. Even though I don't agree with all of it.

CYA!

[second opinion]

I have a customer who would like there Lochnivar Knight boiler cvpc vent pipe changed from a side sill plate vent to a up though the roof vertical vent.
The snow line is a problem even though the vent and intake go up 2 feet from the sillplate. There is a bedroom closet 10 feet to the left of the boiler.
I was thinking of framining in a chase in the corner of the closet and going up though it and out the side at around 8 feet or up though the attic to roof. Lochnivar wants cpvc used for any closet or alcove install. cpvc is rated at a higher temp then pvc but i cant find a section in the fuel gas codebook on plastic venting up though the house. What does everyone think .

CPVC is in the installation manual, and there is nothing in the codes regulating it.