Best way to seal up 2 pvc pipes going thru an existing 8" dia. roof cap (??)

[ilbebauck]

I have an existing 8" roof opening which the previous 65% gas furnace and water heater was vented thru . The last owner abandoned both and went with electric furnace and electric water heater...and simply placed an 8" sheetmetal cap over the roof opening .

I want to install a 95% gas furnace requiring two 2" dia. PVC Pipes (intake and exhaust) and would like to utilize the present 8"roof opening . I could cut two seperate holes thru the existing cap , or, is it better to use one rubber roof jack for both pipes to go thru if such a thing is offered ? I want to have it sealed good against the elements.

Your help is appreciated.

[Steve]

2 words....... concentric vent

[PaxPerPoten]

2 more words HVAC Contractor

[ken]

A licensed HVAC Contractor, not some hack like Dave in Lake Villa or Dave in Illinois....

[ilbebauck]

Bingo-matic ! Thanks.

[PaxPerPoten]

Sounds like a "Dave" fetish to me.

[Daniel who wants to know]

Well since it stands for Heating, Ventilation, and Air Conditioning, it is five words, six if you count the minor word "and".

[Steve]

Ain't that some shit...

[.p.jm.]

Wrong thread - get that shit out of here.

[PaxPerPoten]

Apparently I have been undercharging as I failed to charge all 5 or 6. But on the A/C part I have been charging to sub cooling mostly.