Running two 2" PVC pipes thru one 8" existing roof opening . Whats the best way ???

[JustCallMeDave]

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
.

[b26440510]

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.

You'd probably want to get a concentric vent kit.

[JustCallMeDave]

You'd probably want to get a concentric vent kit.

So a kit where you have a pipe within a pipe to handle exhaust and intake ? The entire kit is then put thru the roof opening then sealed , i take it ??? Ill do a google to see what that looks like. Thanks.

[motoguy128]

You might want to run the cocentric offset in the existing pipe and not centered incase you want to get a direct vent gas hot water heater in the future.

[JustCallMeDave]

You might want to run the cocentric offset in the existing pipe and not centered incase you want to get a direct vent gas hot water heater in the future.

That would be a valid concern, except, I made myself a Solar Hot Water Collector which is giving me some mighty hot water of 145-160 f. ... enough for a daily shower and dishwasher , so I dont use my water heater anymore -- living in FLorida has its advantages :

(http://rimstar.org/renewnrg/diy_pex_...thermal_dn.htm ) .

[b26440510]

So a kit where you have a pipe within a pipe to handle exhaust and intake ? The entire kit is then put thru the roof opening then sealed , i take it ??? Ill do a google to see what that looks like. Thanks.

Yeah, basically turns the two pipes into one. They are make/model specific so check which ones are compatible with your equipment.

[garya505]

Or get an Alumi-flash pipe portal. You can run four 1" to 2" pipes through it, but nothing really hot (i.e. nothing requiring a metal vent). The base is aluminum and it has a EPDM cap. They have one with a single 2" to 6" cap too, if you want to run the concentric vent through it.

[JustCallMeDave]

Ill google the alumiflash pipe portal to see what is looks like . Thanks

[hvacvegas]

I think I would replace the shingles/decking in the area, and put a new flashing at another spot.

[garya505]

Ill google the alumiflash pipe portal to see what is looks like . Thanks

Manufacturer is Commercial Products Group:
http://www.commercialproductsgroup.c...lumiflash.aspx

Or check the Big Rock Supply web site.

[JustCallMeDave]

Manufacturer is Commercial Products Group:
http://www.commercialproductsgroup.c...lumiflash.aspx

Or check the Big Rock Supply web site.

Great. Thanks.

[b26440510]

wow, those seem to be more for industrial. Would anyone need 4/5 vents in one location for a house?

Looks like maybe the portal line would be a bit more practical.

[motoguy128]

wow, those seem to be more for industrial. Would anyone need 4/5 vents in one location for a house?

Looks like maybe the portal line would be a bit more practical.

Sure, 2 gas DV fireplaces, DV hot water heater, 2 furnaces. Not a bad idea to have just a single roof penetration. The fewer holes you can put in a roof the better.