orphaned water heater venting

[arollerblader]

Currently both my gas furnace and the water heater vent pipes go into a Y connection to what seems a 6 inch vent that goes into the chimney space. I am replacing my old 80% gas furnace with a high efficiency one, which will have its own direct vent into the wall. I have one company telling me I have to put a liner to resize the vent for the orphaned water heater and the other telling me I don't. What is the code in NJ for this situation? Thanks for your advice.

[BaldLoonie]

National Fuel Gas Code addresses this. The flow area of the chimney cannot be more than 7 times the outlet area of the water heater draft hood. So with a typical heater and a 3" outlet, that means the chimney can't have an area more than 49 square inches. Pretty rare to have a chimney tile liner that small. Also local codes could be more restrictive.

Regardless, really wise to line it anyway to avoid condensation damage.

We find a lot of dealers around here say you don't need a liner so they have a lower bid and easier install.

[t527ed]

what is the main chimney? masonary or metal b vent up thru the roof?

[ampulman]

Try this.

http://www2.iccsafe.org/states/newjersey/

AM