Monday, January 9, 2017

Navien Tankless Hotwater Heater Leaking

We have a slow leak from the outlet for the Navien's Recirculation Return Connection (RCC). We don't employ an external (through the home) recirculation system, so the return is capped. It's the cap with yellow duct tape on it, next to the Cold Water Inlet Connection (CWIC), in the photo below (I insulated the cold water copper piping in case it was collecting condensation).
Navien NR-180A Tankless Hotwater Heater from the front
We are using the internal circulation mode to speed up hot water delivery to our bathroom outlets. I'm concerned that the circulation pump or 3-Way Valve may be leaking, and water collection in the bottom of the tank is leaking through the capped RCC. The Inlet Water Filter may also be dirty, and this could cause a leak.

Note also the venting for the room, which runs right along side the water and drain pipes (the Navien will sit above this vent). I'm not sure this venting is required. The vent drops very cold air into the room during winter, and may freeze water in the pipes. There is a gas furnace in the room, but it is vented separately.

Vent to outside right under where the Navien will be installed.