Hello everyone

I am back with another issue.

I need to vent 2 water heater and 2 furnace to the roof.
The plan so far is to have a common vertical B vent for all 4 appliance.

I can have both water heater connect to an horizontal B vent located 12" above the draft hood of the WH and would run horizontally for 12' up to the common vertical B vent.

I can do the same for the furnaces. Connect both of the to an horizontal B vent that would run horizontally for 8' before connecting to the vertical B vent below the WH connection.

Would this be ok code wise? I am in California.

I am just really about the 1 1/2 time rules versus the 100 % of vertical vent.

Any suggestions would be appreciated

what you propose to do sounds fine..
everything is spelled out here..
[www.hartandcooley.com]

Thank you packy. That s a great link. I got my head spinning with the sizing thing. 50000 but for WH and 46000 for the furnaces for a total 192000 but. Looks like I am going to need a big common vent.

Now, I have to figure out if my furnace are draft hood or fan assisted. They are Bryant plus 80 but there is nothing online about it. And there no draft hood on them like the WH.



Edited 1 times.

It is usually internal.

follow the drawings..
you can step down the tees as you progress away from the vertical chimney.
without looking at the chart i'm guessing 6 inch but might be 7 ??
they want the chimney to be minimum size. keeps down on condensation.
so the first tee might be 6 x 5 x 4 (assuming the furnace is 4)
the next might be 5 x 4 x 4 and the last tee 4 x 3 x 3.. again assuming the furnaces are closest to the vertical.
but you get the idea.
the 4 x 3 x 3 might even be a galvanized tee not b-vent..
do check the sizes against the charts as i am only giving you a general idea..