Here is one for you Electronic experts.

[DavidApp]

I have a Thankless water heater that is malfunctioning.It is a Rheem EcoSense RTE13. Some times it heats and sometimes it does not. You have to turn the water on and off several times then it works.
I am not an electronic guy but I do have some basic skills.

I have replaced it with a Bosch system that does not do a great job. Not sure if there is a problem with it or that is how it works.

On the Rheem there is a switch that I am presuming is a flow sensor that would turn on the heating elements. I am not sure how it works. Look like a Reed switch to me. What would cause it to close when the water flows? I have not removed the screen on the inlet to see if there is anything directly under the switch.

David

This is the switch.

 

[George_H]

I would think it is a bi-metallic strip that looks a a temp. change when cold water goes in??

 

[PAUL161]

Ever consider Lime deposits causing the switch to intermittently work? I don't know your switch, but lime in an older system can cause problems. PJ

 

[DNK]

There's also a pressure switch so it won't heat till therew is enough water pressure.

 

[DavidApp]

Hello All.

Thank you for your responses.

Had not thought about a Bi-metallic strip. I could test it with a meter and run some water through it to see if anything happens. The screen in the inlet seems to be soldered in place.

Our water is acidic and I am adding soda ash to neutralize it. There is no lime scale in our counter top kettle.

We are on a well so our water pressure fluctuates from 40 to about 60psi. I have removed the screw shown in the photo and there is nothing under the board but there is a slot in the board that would suggest longitudinal adjustment.

David

 

[DNK]

...We are on a well so our water pressure fluctuates from 40 to about 60psi. I have removed the screw shown in the photo and there is nothing under the board but there is a slot in the board that would suggest longitudinal adjustment.

David

Has nothing to do with what your pressure is.
Most heaters have a controller to set minimum pressure before it turns on

 

[Jerry]

I have 3 units in my house. They have a computer board on all three and it is very picky about everything running right. One of sensors picks up particles in the combustion chamber and will shut down if they are there. I have to take the chamber out an clean it so the error will turn off. With the computer board, there is a series of lights that blink out an error code. Once you have the code, you can determine the solution.

 

[TR3driver]

A little Googling produced this page:
https://usatankless.com/collections/parts/products/reed-switch

Looks like exactly the same part in the photo (even with the E226633 part number visible), description says it is a reed switch and there is a magnet inside the pipe that gets deflected by water flow.

First step would be to test if that sensor is actually the problem. Might take some detective work to discover what the control voltage is; fortunately modern digital meters are pretty tolerant. So look for voltage across the reed switch with no water flowing, then with water flowing and the heater working, then with water flowing and heater not working. Obviously the voltage will go away when the switch closes. So the tests will tell you what it should do, and whether not doing that is what is blocking the heater from operating.

 

[DavidApp]

Hello Randall

Thank you.
I had looked for that switch a while ago with no luck. Bookmarked the page now.

I have just tested the reed switch with a magnet and it works. It may be that the location is important as I see there is a slot in the board.

As the unit is off the wall and not connected to the water supply at the moment I can not try the flow test. Something I will have to work on next week. If I can get it working I will re install it as it is a better unit than the Bosch. May install them in tandem so I can switch between them as I don't think I can return the Bosch unit. Will call them in the morning. The Bosch unit comes on OK but you have to have full flow and any drop in flow shuts off the heating element. The directions say to use the outlet valve to regulate the flow if the water temperature is too low. It struggles to maintain 115 degrees.
Our cold water is 60 degrees.

David

 

[70herald]

Hello Randall

Thank you.
I had looked for that switch a while ago with no luck. Bookmarked the page now.

I have just tested the reed switch with a magnet and it works. It may be that the location is important as I see there is a slot in the board.


David

OK so where is the magnet which is supposed to trigger the reed switch? Inside the pipe hiding behind the circuit board. That switch is probably oriented vertically right? (of course it is) the numbers on the side of the slot are the flow rate so if you move it the circuit board you can adjust the minimum flow rate where the switch will turn on. The water flow pushes the magnet upward. the higher the flow the further up the magnet will be pushed.
Take the water pipe out and clean it. most likely, some sort of crude has built up in there and the magnet / float are stuck.

It will look like this: (but of course will have a magnet for the sensor.
https://www.banggood.com/LZS-15-12-...uid-Flowmeter-p-1430794.html?cur_warehouse=CN

 

[DavidApp]

Got the magnet thing out of the heater and could see what the problem was. The plastic part that encases the magnet had split and the magnet had corroded away.

As the Bosch heater is not as good a unit as the old one I will be buying the parts and reinstalling the old heater.

Thank you Randall for the link. I was looking for the Rheem heater not the Titan.

This is an amazing forum. We fix your car or water heater.

David.

 

[DrEntropy]

Twenty-five years on line, nearly twenty-five THOUSAND folks with different life experiences. Different disciplines, different expertise. The place is a treasure! :thumbsup: