Just did a large house today. Besides the other gas water heater in the garage the house had this Rinnai R53 tankless gas water heater in one of the closets off the master bathroom. Solid door leading into this 5x6 closet…I am assuming that this unit is the same as any gas water heater in that they need to put a louvered door on the closet and install a drain pan under the unit?
This looks like a power vent unit that draws combustion air from the interior but Rinnai also has a concentric venting system that uses one vent for both intake and exhaust…
I just inspected one today that had separate out and intake PVC pipes, but also a 3rd terminating in the closet. Just an elbow with a screen on it, for, I assume fresh air from a closet.
I was wrong. On second glance there are only two and the exhaust is only a single 2 inch pipe which means it is not concentric and does not double as intake, so its only getting fresh air from this tiny closet. Guess I’m writing this up!