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We have a Rheem tankless water heater that doesn't turn off…

Customer Question
We have a Rheem...

We have a Rheem tankless water heater that doesn't turn off when the water is shut off. If the water is on full and then turned off quickly, the heater shuts off. If the water is running slowly and then turned off, the two red indicator lights on the heater go from solid to flickering and if you turn the water on again it will be dangerously hot.

Contractor's Assistant: How long has this been going on? And how severe is the problem?

Pretty much since it was installed. A And it is consistent in doing so.

Contractor's Assistant: Do you plan on doing the work yourself?

If possible, but I'm pretty handy.

Contractor's Assistant: Anything else we should know to help you best?

I did fix one years ago when it wouldn't turn on. The little whirly thing in the sensor was stuck on a bit of trash. I just took it apart and cleaned it.

Submitted: 6 months ago.Category: Plumbing
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Answered in 20 minutes by:
1/9/2018
Plumber: Phil, Mechanical Engineer. replied 6 months ago
Phil
Phil, Mechanical Engineer.
Category: Plumbing
Satisfied Customers: 9,718
Experience: Retired mech. contractor, shop owner, 51 yrs experience.
Verified

Hello, there is a 'flow switch' inside the water heater that shuts the burners off when flow drops below 0.5 gallons per minute, the problem is that its *sticking. That is caused by calcium carbonate (hard water deposits) building up inside the water heater.

.

For that reason these types of water heaters must be flushed regularly with white vinegar, in some areas once a year depending on how hard the water is.

.

Here is a video on how thats done, your water heater will not be identical but it will be very similar.

Click here please

.

We can go from here without any time limits as needed. You can also have this done by a local plumber for $250 or so if the acid flush valves were installed with the heater.

.

My goal is to give you the best experience possible! I hope I have earned a 5 star rating! Please remember to rate my service by selecting the 5 stars at the top of the screen before you leave today. If you need more assistance, please use the reply box and let me know.

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Phil, Mechanical Engineer.
Category: Plumbing
Satisfied Customers: 9,718
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Experience: Retired mech. contractor, shop owner, 51 yrs experience.

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