Water Flow Sensor Assembly, 107000683

steady hot water now.

Replaces the stock water valve (water turbine) assembly on Rinnai RU199IN. It is an exact replacement (even if the parts numbers don't line up as the original part was discontinued by Rinnai). We kept getting a "no code" error where the tankless would not heat the water flowing through the tankless even when all the taps were set to hot water. Issue would occur intermittently. Called 3 local plumbers to assess the "no code", no hot water issue. None would assist because there was no code. But one did offer to tear out and install a new one for $7,000 (installation cost only) + the cost of a new tankless. Took about 2 hours to self-install (lots of stuff in the way) and flushed the system after the install while the tankless was disconnected (3 hours total). It has been 3 weeks and no loss of hot water since the replacement - seems to have done the trick! Would recommend.