I need to install a second power vent water heater (new master bath/whirlpool) and had assumed I'd need to have a second PVC vent line run out the side of the house. However, a contractor friend thought it was possible to share the existing vent line.
Seems to me that without some sort of damper - the exhaust from one water heater might back feed to the other water heater and enter the utility room.
Also - will the existing 1/2" gas line be sufficient for both heaters? They will rarely run simultaneously as I'm installing them in series and the first in the series (which will feed the second heater) will have a remote control which will only allow it to turn on when we're planning to need the extra capacity (e.g. whirlpool use or overnight guests).