Why My Rheem Water Heater Keeps Turning Off [Solved]

Rheem water heater keeps turning off due to a clogged or damaged thermocouple, dirty pilot tube, blocked air inlet, and a faulty gas control valve.

Besides, the major reasons for Rheem electric water heater keep shutting down include a bad thermostat, burnt-out heating element, loose wiring, or an electrical short in the breaker.

rheem water heater keeps turning off

Whatever the reason, you will have to inspect the thermocouple to determine if it is dirty or damaged. Then, you need to clean the dirty pilot tube, the buildup of dirt from the air screen, and replace the faulty gas valve. 

In the case of an electric water heater, you will have to replace the bad thermostat or burnt-out heating element and fix the issue from the electrical source. Read through our below guide to get the details. 

Why My Rheem Water Heater Keeps Turning Off [Solved]

Throughout this article, we have explored all the responsive factors behind continuously turning off issues for both Rheem gas and electric water heater. Also, learn how to resolve this problem effectively:

Note: You can also read how to fix Rheem water heater failed ignition lockout.

1. Clogged Thermocouple

If your Rheem hot water heater keeps turning on and off, the thermocouple would be the first culprit.

The thermocouple is the essential part of the pilot burner assembly attached to the gas control valve. It works as a sensor in the system and generates a small electrical current when it’s heated by the pilot flame.

This current senses the gas valve to keep open the gas supply, and the heater continues functioning. But malfunctioning of the thermocouple creates an obstacle in the heater heating system.

It might be clogged with debris or accumulated dirt particles. So, you will have to concentrate on the thermocouple and clean the element.

How To Clean Thermocouple On Rheem Water Heater

Before cleaning, collect some necessary tools like steel wool or 60-grit sandpaper, emery cloth, and a microfiber towel. First, disconnect the gas supply. Then, disassemble the gas burner assembly to access the thermocouple.

Start cleaning by sanding the thermocouple ends using an emery cloth. This will clean the stubborn stains from the thermocouple body. You can use steel or 60-grit sandpaper alternatively.

clean the thermocouple

After that, look for corrosion between the terminal and the power wire. Wipe it away. Finally, wipe down the sanded areas with a microfiber towel. That’s done the cleaning. Now reassemble the burner assembly and turn on the gas.

2. Damaged Thermocouple

After cleaning the thermocouple, if still, the Rheem gas water heater keeps cycling on and off, be sure the thermocouple is defective. Sometimes, the thermocouple bents and is beyond repair. Also, irregular voltage reading is another leading reason for its defection. 

The well-functioning thermocouple will give a voltage reading of 30 to 40 millivoltsBut if the reading is below 25 millivolts, this is a big sign of a faulty thermocouple. The only solution to get rid of this problem is to replace the bad thermocouple. 

How To Replace Thermocouple On Rheem Water Heater

  • Before replacing the thermocouple, make sure the water heater is unplugged and disconnected from the gas supply.
  • Now, remove the burner assembly to detach the thermocouple.
  • Install the new thermocouple in the accurate place.
  • It would be best to tighten the thermocouple with a wrench to set it properly.
  • Then, reconnect the entire system of the burner assembly with the thermocouple.

3. Dirty Pilot Tube

The pilot orifice is an integral part of the burner assembly that controls the gas flow to the pilot. It mainly functions to light the gas and ignites the main burner. When the water needs heating, the valve starts releasing the gas and ignites the burner with the help of a pilot light.

Also, the pilot light heats the thermocouple, which creates a small amount of electricity after sensing the heat. If the pilot tube gets dirty from soot, dust, and other particles, it fails to signal the gas controls to turn on.

Also, a clogged pilot tube prevents the pilot light from lighting altogether, causing the heater flickers off. So now you need to clean the pilot tube.

How To Clean Pilot Tube On Rheem Water Heater

  • Turn off the gas supply at the first step.
  • Leave the unit in this situation to let the pilot tube cool.
  • Now locate the pilot light and disconnect it from the connection.
  • Take a wire brush or stiff-bristled brush and start cleaning the tube.
  • You need to brush away the carbon and soot build-up from the tube.
  • Then, scrape off the dust from the exterior of the tube surface and wipe away dust using a soft cloth.
  • Reassemble the pilot light to its place.
  • As it is the most sensitive part of the heater, so it is a good recommendation to clean the pilot every six months for good maintenance.

4. Blocked Air Inlet

If there is no proper air circulation in the water heater, the chances of the heater turning off randomly increase. A blocked air intake screen is the first reason for poor air circulation in the heater system. 

The air intake screen can easily be blocked by lint and soot buildup, creating combustion air restriction, and the burner will not get enough gas to ignite. This leads to the hot water heater keeps going out. 

How To Clean Rheem Water Heater Air Intake

First, turn off the heater and shut off the gas supply. Then locate the air intake screen of your water from the base of the water tank on the front of the unit. To access the air intake screen, you need to slide out the burner assembly.

Now start cleaning the air intake screen with compressed air. It will suck up all the dirt and debris from the air intake screen. Just Run the compressed air across the air intake screen back and forth.

clean rheem water heater air Intake

You can use a paper towel dampened with water to remove excess dust buildup. After cleaning, reassemble the burner assembly and turn on the gas supply.

5. A Faulty Gas Control Valve

If all the above troubleshooting steps fail to prove well, be sure the faulty control is most likely to blame in this case.

Due to the defective gas control valve, the gas supply to the pilot light or burner is interrupted. For this, you are experiencing a hot water heater that keeps cutting off.

Here, either the gas is leaking, or the gas valve’s inner elements are being damaged. The gas control valve itself may have simply worn out or been defective. Whatever the reason is, only replacing the damaged gas control valve can resolve the issue.


If you are in the chore of fixing the gas control valve issue, contact a certified plumber for precisely doing the task. They will better suggest either the gas valve needs replacement or only a repair can fix the bad control valve problem. 

After recovering the gas control valve, you can hope to fix the Rheem gas water heater that keeps cycling on and off. Also, the heater will get back into operation. 

Rheem Electric Water Heater Keeps Shutting Off [3 More Reasons To Fix]

If your Rheem electric water heater keeps turning off, there must timely 3 major reasons to blame. As the electric water heater is electrically operated, thus the main culprit behind the randomly turning off issue is an electrical glitch within the heater system.

Either there is an electrical short in the breaker or the heater’s thermostat is defective. At times, the essential heating element has burnt out, causing the water heater keeps losing power. Get the details below:

i. Bad Thermostat

In every electric water heater, you will find 2 thermostats, an upper and a lower one. There is a reset button located on the upper thermostat.

The main function of the thermostat is to monitor the water temperature of the water heater. If it reaches the set temperature, the thermostat turns off the heating element.

Now for malfunctioning of the thermostat or if they get stuck ON, the reset button of the thermostat gets tripped.

Sometimes, there has a bad reset button or a broken thermostat issue. For this, your heater won’t work correctly. Here, you will have to replace the defective thermostat.

How To Replace Faulty Thermostat In Rheem Electric Water Heater

  • First, disconnect the heater’s power connection.
  • To access the thermostat, remove the access panel and disconnect the safety cover.
  • Disconnect the wiring from the thermostat as well.
  • Locate the thermostat from the special bracket that holds the device against the tank.
  • Loosen the screws of the thermostat. 
  • Then, gently pry out the bracket from one side by twisting that side of the thermostat upwards. 
  • Disconnect the other side in the same way.
  • Also, remove the lower thermostat from the bracket.
  • Install the new thermostat by sliding them evenly downwards into the holding brackets. 
  • Reattach the wires. 
  • Connect the plastic cover and then place the folded insulation back in place. 

ii. Burnt Out Heating Element

Rheem electric water heater features two heating elements which are controlled by the thermostat. The burnt-out heating element is the most common culprit when your hot water heater keeps turning off. Here the heating element might be experienced a short o they are broken. 

Due to the shortage in the heating element, it will continue the function even after the thermostat stops working.

By this, the inside water temperature reaches more than 180 degrees, tripping the reset button and turning off the heater. So, in this troubleshooting stage, you have to replace the bad heating element.


  • You can assure of a bad heating element by testing the continuity of the elements.
  • To test the short circuit of the element, you need an alligator clip and tester probe. If the result shows negative, replace the faulty heating element.
  • Contact any professional to replace it. 

iii. Loose Wiring Or Bad Breaker

If the thermostats and heating elements are functioning properly, there may have loose wiring on the circuit board.

Also, there might be a higher possibility that your home’s breaker has worn out. In both situations, the reset button of the thermostat gets tripped, causing the heater shuts down.


  • First, reset the circuits. For this, disconnect the two-wire connectors from the circuit board.
  • Wait for 10-20 seconds and then re-connect the wiring back to the circuit board.
  • Replace the wire if it is worn out. 
  • Also, check the wiring of the igniter and ensure all the wires are snugly connected to their proper locations.
  • Fix the breaker that has worn out or tripped with the help of an electrician.  
  • Reassemble the heater, and all the issues corresponding to the power should be resolved.


Why won’t my pilot light ignite on my water heater?

A bad thermocouple is the first reason for malfunctioning in the pilot light. Either the thermocouple is dirty or damaged, which prevents the pilot from being lit. After cleaning the dust buildup from the thermocouple, you need to relight the pilot light.  

How long do water heater thermocouples last?

The fact generally depends on your maintenance and how you have installed it. But from the manufacturer’s recommendation, a water heater thermocouple will last up to 10 years. You have to be always concerned about the cleaning of it

Wrapping Thoughts

To the ending point of the guide, hopefully now have a crystal clear idea about the reason what do you do when your water heater keeps turning off.

Follow the above well-proven guide and attempt each of the troubleshooting steps if your Rheem tankless water heater won’t stay on. 

Well, that’s all!! But still, if you have queries or questions on any discussed fact, don’t delay to ask us through comments. We are always here for you. 

About William

William is the founder of Fireplacehubs.com. He has real life practical skills in fixing smoker & heating appliance issues. He loves to share his knowledge & helps others in fixing their appliances & saving their money. William firmly believes that anyone can repair his or her unit with the correct guidance & knowledge. See more at about us.

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