Sam S.
New Member
I am in a 35 year old condo on the ground floor of a 2-1/2 story building, and would love to replace my aging 40gal. with a natural gas tank-less. I'm working under some constraints, primarily that of the venting which can't realistically be altered.
The current heater uses a 3" vent piped into the side of a 5" vent originating from the alongside furnace, leading up to the roof, and constructed of galvanized steel.
Given the high vent output temperatures of conventional tank-less heaters, they would not work in this scenario, but I'm reasoning that a modest-sized (I'm looking at a 6.6gal/min. one) condensing one might, since they only produce temperatures under 150 degrees F.
The problem I'm encountering is twofold:
1. The manufacturer doesn't approve of a shared vent.
2. The units seem to be designed for PVC venting, and although 3" diameter is okay, it's unclear whether it's allowed to be connected to metal!
I don't really understand all this fussiness about the venting, given the relatively low temperatures involved. There is a separate condensate drain, so presumably the exhaust wouldn't be producing anything acidic/corrosive.
Also, my (short) gas line is only 1/2".
Does anybody have any insight and/or suggestions?
I'm getting ready to just give up and go to a 30 gal. tank, but I'd really rather give this a try!
The current heater uses a 3" vent piped into the side of a 5" vent originating from the alongside furnace, leading up to the roof, and constructed of galvanized steel.
Given the high vent output temperatures of conventional tank-less heaters, they would not work in this scenario, but I'm reasoning that a modest-sized (I'm looking at a 6.6gal/min. one) condensing one might, since they only produce temperatures under 150 degrees F.
The problem I'm encountering is twofold:
1. The manufacturer doesn't approve of a shared vent.
2. The units seem to be designed for PVC venting, and although 3" diameter is okay, it's unclear whether it's allowed to be connected to metal!
I don't really understand all this fussiness about the venting, given the relatively low temperatures involved. There is a separate condensate drain, so presumably the exhaust wouldn't be producing anything acidic/corrosive.
Also, my (short) gas line is only 1/2".
Does anybody have any insight and/or suggestions?
I'm getting ready to just give up and go to a 30 gal. tank, but I'd really rather give this a try!