Excellent Plumber Needed for consult

[smonday]

I need an extremely experienced plumber to weigh in on a difficulty I'm having with a newly installed tankless water heater (Noritz brand) that is making a groaning noise when the hot water is turned off. The current plumber and the sales reps/techs from Noritz can't tell what is causing the noise.

[Shandi]

Googled this issue and found:

"Tankless water heaters will all make some noise when starting up and heating water, but the noise levels are usually reasonable and not cause for concern. When the noise occurs when there is no hot water being used, it's likely there is a vacuum that's siphoning water away from the unit and causing loud noise and vibration. In most cases the solution is to have a plumber install a check valve in the water line to prevent other plumbing fixtures from interfering with the flow of water to the water heater.

Another common problem that can create noise in tankless water heaters is a dirty flow sensor which controls how much gas is sent to the unit. Other sources of noise include blocked or inadequate ventilation or a defective or improperly set pressure valve."

I need an extremely experienced plumber to weigh in on a difficulty I'm having with a newly installed tankless water heater (Noritz brand) that is making a groaning noise when the hot water is turned off. The current plumber and the sales reps/techs from Noritz can't tell what is causing the noise.