Rheem Water Heater keeps turning off because of the following reasons:
- Defective thermocouple
- Tripped Thermal Release Device
- The air screen or filter gets clogged
- Grill on the underside of the gas tank gets dirty
- Faulty gas control valve
Throughout this guideline, I will break down how to troubleshoot each of those components. As a result, you can easily discover the reason that causes the water heater to keep shutting off and fix it.
Without further ado, let’s dive in.
Why Does My Rheem Water Heater Keep Turning Off?
Your Rheem Water Heater Keeps turning off because of a bad thermocouple, a tripped thermal release device, a clogged air screen, and bad gas valve. You can bring the unit back to the normal state once you determine which one of these issues causes the problem and solve it.
Below, I will walk you through every troubleshooting step to detect the main culprit responsible for the water heater turning-off issue. So, keep reading.
01. Bad Thermocouple
One common water heater issue that can throw a wrench into work is a defective thermocouple. The pilot light will keep going out or won’t stay lit because of a bad thermocouple.
If the pilot light goes out, the thermocouple will cool down. As a result, the voltage will drop and the gas valve will shut off. In short, you can’t turn on the water heater if the thermocouple is at fault.
How To Fix:
Start with testing the thermocouple electrically to determine whether it’s at fault or not. Regarding this, remove the bottom cover first. Then, get a multimeter and set it to the volts DC option. Now, use an adjustable wrench to remove the thermocouple from the gas control valve.
What you need to do next is- connect the probes to the copper and to the end of the thermocouple. Light the pilot and hold down the button. You can see now the voltage will start to rise over the next few minutes as the thermocouple heats up.
A healthy thermocouple will give you a reading between 20 to 30 millivolts. If the voltage goes out of range, you must replace the thermocouple. Overtime, the thermocouple gets covered with dirt or debris buildup, which reduces the voltage.
In this case, get an emery cloth and clean the thermocouple with it. But it will be best to install a new thermocouple. The following video will help you a lot in new thermocouple installation:
02. Thermal Release Device Gets Tripped
Most plumbers or water heater owners have a tendency to blame- either the thermocouple or the gas valve if your Rheem unit keeps shutting off or its pilot keeps going out.
Of course, the failure of these two components is responsible for the pilot light issue. But no one ever talks about the TRD or Thermal Release Device of Rheem.
FYI: Every Rheem tank water heater has a safety device in the combustion chamber called TRD or Combustion Shut-off Device (its other name). It contains a small glass bubble or vial filled with liquid. This device is specially designed to cut off the fresh air entering the combustion chamber in the event of overheating issue.
If the TRD gets tripped, you can’t turn on the unit. Indeed, the unit will keep turning off every time you try to start your water heater until you replace it.
Generally, the following reasons described below are responsible for a tripped Thermal Release Device:
- Gas pressure goes out of range or tolerance (number 1 culprit)
- Improper air flow at the intake manifold
- Presence of flammable vapor
- Improper venting
How To Fix:
To access the Thermal Release Device (TRD), you must remove the bottom cover. Ensure you turn off the gas supply to your Rheem water heater. Then, disconnect everything from the gas control valve. Next, remove the burner assembly.
Now, take a flashlight and look for the Thermal Release Device, which you can find in the middle of the combustion area. Inspect it visually and see whether there is any sign of crack or damage on it. If it gets damaged or broken, pull it out. Then, install a new thermal release device.
Keep in mind; it’s a bit challenging to mount or unmount the TRD. So, I recommend you hire a professional to do this task for you if you are uncomfortable with it.
03. Air Screen Gets Clogged
If the thermal release device of the Rheem unit is fine, the air screen or air filter below the TRD is the next component you should inspect. A clogged air screen prevents the outside air from entering the combustion area.
Because of lack of oxygen, the pilot light keeps going out. Generally, the air filter or screen gets restricted due to dirt, debris, and hard water mineral deposits.
How To Fix:
Again, it requires you to pull out the bottom access cover of the unit. Then, detach everything like wires, gas lines, and others from the gas control valve. Then, remove the burner assembly from the combustion chamber to access the air screen or air filter. This is how the air screen looks like:
Now, take an air compressor to blow away dirt and debris. You can even apply vinegar solution to the filter with a spray bottle. Then, use a brass brush to brush up the air filter evenly. Finally, blow out the blockage with an air compressor.
04. Grill On The Underside of the Gas Tank Is Dirty
Every tank water heater (including Rheem) has a grill on the underside of the gas tank. Through the pathway of the grill, air or oxygen makes an entrance to the burner chamber.
If the grill or its pathway gets clogged by dirt and debris, air can’t flow through it and reach the combustion area. And without air or oxygen, your Rheem water heater won’t light as fire needs oxygen. In other words, a plugged up grill makes the unit too hot (as new air fails to go into the burner), which trips the high limit switch.
In short, a dirty grill underside of your Rheem water heater gas tank causes the unit to keep shutting off.
How To Fix:
You must remove the cover plate to get access into the grill on the underside of the gas tank. Then, get a small wire brush to brush up that area evenly to wipe away every speck of dirt and lint.
You can also use a vacuum cleaner to suck away dirt & debris from that area to allow the air flow into the combustion area. I hope it will solve the continuous turning-off issue of your Rheem water heater.
05. Gas Valve Issue
If the above troubleshooting steps bring no luck for you, the last component you should inspect is the gas control valve. A failed gas valve will cause the unit to go off. Gas leak and a complete shut-down unit are two common signs of a defective gas valve.
How To Fix:
I already covered a guide on the Rheem Water Heater Gas Valve Problem, where I broke down how to replace a gas control valve. So, check that article and make the replacement by yourself. Alternatively, you can call a certified plumber to do this workflow for you.
How do you clean a thermocouple on a water heater?
Cleaning a thermocouple on a water heater is not rocket science. Just remove the bottom access panel of your water heater and slide out the burner assembly from the unit. Then, locate the thermocouple on the burner assembly and detach it. Now, get an emery cloth to rub the thermocouple gently to remove dirt and debris.
How do you know if your water heater thermocouple is bad?
The best way to know whether a thermocouple is bad or not is to inspect it electrically. A functioning thermocouple will give a reading between 20 to 30 millivolts. If the reading goes out of range, understand the thermocouple is bad. At the beginning of this article, I described how to test the thermocouple electrically.
How long do thermocouples last?
A thermocouple will last around 10 years if you install and maintain it properly.
I broke down all the possible reasons that cause your Rheem water heater to keep turning off. What you should do now is- just follow the troubleshooting steps I mentioned to detect the culprit behind this issue. Then, solve that problem to get a functioning water heater. That’s it!
Eric Alvarez is an HVAC guy based in El Paso, Texas, United States. He obtained his Bachelor of Science degree from the University Of Texas at El Paso. Years of experience in the HVAC field have taught him many lessons, not the least of which is that the value of quality and knowledge far exceeds any promised initial savings. He has a good standing reputation for superior skills in heating, air conditioning, hot water tanks, and indoor air quality systems.