Why My Rheem Water Heater Tripping Breaker [Solved] 

Your Rheem water heater tripping breaker due to breaker problems, power surges, damaged thermostats, or a faulty electrical panel in your heater. In most cases, you can fix problems by avoiding overloading or checking your breakers regularly.

Whatever the issue, we have figured out the common reasons for the breaker’s troubles and outlined their easy solutions. Hopefully, you’ll be able to fix your circuit breaker’s tripping issues definitely by yourself if you follow our below tips. So let’s go ahead.

rheem water heater tripping breake

Rheem Water Heater Tripping Breaker [Solved]

In this part, we will explore why your Rheem tankless water heater breaker is tripping and also suggest how to fix it easily. So, read between the lines.

Note: You can also read how to fix the Rheem water heater keeps turning off.

1. Main Breaker issues

A defective main breaker is one of the most common reasons for tripping your Rheem tankless heater’s breaker. You may have lost power in any part of your water heater, or throughout the entire heater because of a defective main breaker.

 main breaker issues

Functionally, the main breaker controls the power supply to all areas of your water heater. So, if it gets tripped or shuts off, it will shut down electricity to all the parts, including the sub-breaker in your water heater’s electric functions or system.

When the power of any section or a single part of the heater goes out, it signals that you have a problem with the sub-breaker. On the other hand, when the power goes out from your water heater, it indicates that the main breaker has tripped.

In this event, outside sources of overload are mainly responsible for the main breaker’s tripping. Normally, when a circuit is falling down, the sub breaker gets overloaded. Then, the main breaker serves as an alternative backup safety, and it may trip to compensate for an overloaded circuit.

After all, the system means that outrage is crossing through your electric panel. Finally, your main breaker may have shut off due to providing backup for the heater, preventing a great loss.


  • If there is a problem with the sub breaker, you can simply turn it on. But when the main circuit breaker goes out, then you need to follow a few steps to safely restore power to your tankless water heater.
  • First, turn all the main breaker switches to the OFF position. Because when a breaker trips, it will remain in a neutral position.
  • Shut off each sub breaker; don’t try to restore all power at once after an outrage. To make sure, you can use a multimeter to test the power.
  • Then, it is easy to get a sound as it makes a sound. Turn the switch of the main breaker to the “On” position.
  • Follow the main power supply by switching each sub breaker to the ON position. Now, wait for 5 seconds to ensure the gradual restoration of the power to the water heater. Don’t expect to get a large demand for power immediately, otherwise, it may cause to trip once again. You can Watch the below video for what causes your heaters breaker to trip and how to solve it.

2. Overloaded With Electricity

Overload is another common reason for your Rheem tankless water heater to keep tripping. This may occur when you expect to get a huge electric demand on a particular circuit beyond the capacity of its limit.

As you know, a circuit breaker is designed to take a certain loading capacity. Again, your circuit breaker may trip when too many fixtures are in use simultaneously. 

For example, if you run a bath and a dishwashing tap at the same time, the breaker may become overheated, putting all the electric system panels connected to that circuit at risk and causing them to trip.

Therefore, if the circuit is capable of taking a load of 15 amps but you are using 20 amps, this is not the fault of your water heater but there is an issue with the system you are using. Then, the breaker gets overloaded and remains shut off automatically.

And consequently, your circuit breakers fail to prevent themselves from receiving any additional flow of electricity. Finally, it may cause electrocution.


  • If your heater’s circuit breaker is tripping out repeatedly, then it indicates that your circuit has been overloaded because of demanding too much power from the circuit.
  • First of all, check how many people are using the water fixtures; otherwise, your circuit may be maltreatment because of overloading the system.
  • Try using fewer appliances at once to keep your heater’s circuit safe. Because this unit is designed to run simultaneously with a circulation process.
  • Then, to fix overloading troubles, you should reset the unit. If the problem is not solved yet, it will reset itself. Otherwise, you need to manually restart the system. Keep in mind, that it doesn’t indicate anything is broken, just you need to reset your circuit breaker.
  • Again, if it is needed, redistribute your devices onto different circuits. You can upgrade your circuit system to fulfill expectations. Hopefully, the overloaded issue will be solved.

3. A Malfunctioning Thermostat

A faulty or defective thermostat is the most common cause of breaker tripping on your Rheem tankless water heater. In fact, the thermostat allows you to heat up all the heating elements at once. Normally, heating elements are controlled by their individual thermostats.

malfunctioning thermostat

Functionally, an electric water heater has a limit switch. When the water reaches 180 degrees, the limit switch trips to prevent something from getting burned by excessively hot water. In most cases, they switch trips due to a bad thermostat. But if it fails to perform properly, the heating elements create excessive heat, and this high heat causes the circuit breaker to trip.

On the other hand, when the thermostats can’t communicate with the heating elements, they go bad and sometimes get stuck in the ON position. Even your heater’s thermal switch may trip if the water heater doesn’t get sufficient air. Then, if it is tripped, you will hear an audible sound like ‘click’.


  • First, find the thermocouple next to the pilot light. Verify whether it has defected. If you can’t hear the sound from the thermocouple, then try to light the pilot according to the instructions in the user’s manual for the heater.
  • Next, make sure the power to the water heater is OFF. Check the thermostat with a multimeter. Disconnect the wires from the thermostat and the thermostat resistance. Normally, there should have no Ohms. 
  • You can now restart your water heater to fix the thermocouple troubles. If your breaker’s issue isn’t fixed, it is now urgent to replace the thermostat.
  • Remember that before replacing the thermocouple, make sure there is an issue with the heating elements, and you can easily test this issue with an electrical tester. The electrician also recommends changing the heating elements if there is an issue with the heating elements.

4. Water Leakage Problems

A leak is a next issue that allows water to come into contact with the electronic parts and causes the breaker to flip. It may be caused by a failing gasket for the heating elements and dipping water in the electric lines. This may be devastating and could cause an electric shock.

Additionally, this serious problem may happen when the temp, pressure release valves, and pumping connections become leaky. However, this is not too tough to fix. 


  • Make sure there is no leak and there is no water contact with the heating elements. If the breaker has not already tripped, don’t forget to turn off the circuit breaker and repair the leak.
  • Check to see if the pressure release valves have any leakage. If the valves are leaked, install a water expansion to reduce the pressure of the flowing water. It will protect your devices from hazardous explosions.
  • Always verify the units so that electricity can pass through them easily.
  • If the tip doesn’t work well, change or replace it with a new one.

5. Short /Faulty Circuit

When there are no issues with the thermostat, heating elements, leakage, or internal wiring, we can bet, there are problems lying outside with the heater. In this case, there is either a short circuit, damaged wiring, or bad connections in the electric panel that are mostly responsible for your Rheem tankless water heater’s circuit breaker tripping.

Again, this problem happens when there is a fault in your electrical outlets, or a fault, or a loose connection in the wiring of the panel. Sometimes, your wiring may be damaged if some animals like mice chew the wiring leads to the water heater.

In this case, when you notice there is a bad, burning smell and discolorations around the circuit, it means there is a short circuit with the breakers. Because the burnt-out heating element is also responsible for the loose connection and tripping the breaker.

As a result, too much current will flow through the circuit, and electrical resistance will be overridden as usual. This produces creates too much heat for the circuit, and the breaker starts tripping to shut off the circuit, saving you from any firing issues with your water heater. Let’s see how to fix the problems.


  • First, pinpoint the circuit panel for a breaker and test the voltage of the heater. 
  • Inspect the wiring in the line for loose and damaged wires. Then, if the breaker trips, it indicates that there are no issues with the line but problems with the circuit breaker.
  • Then ensure the breaker is in the OFF position. Some breakers have a light to stay lit if they get tripped. If it is in the OFF position, switch it ON and OFF, and then back to the ON position to fully reset. It may take additional time. But this process will restore power.
  • Yet, if the breaker shuts off again, there might be a short in the panel and the system will still be unable to restore power. 
  • Make sure all the connections are good to the breaker. If you find any loose connections, reconnect them tightly. You can test it by plugging the lines into different circuits. Then, it would be best to have a periodic audit of the circuit board.
  • If you are unable to solve the above issue, your circuit breakers may have worn out. Now, don’t hesitate to call a certified electrician to find out the inner faults to maintain your circuit breaker.
  • Yet, if it is needed, replace the breaker with the same rating. Because a high-rated breaker causes overheating and trips the breaker again.

Rheem Tankless Water Heater Error Code With Breaker’s Problems

Rheem tankless water heater will show several error codes if the heater faces some critical issues with the breakers tripping.  Luckily, the tankless water heater is designed to display an alert message about what is going on with the circuit breakers.

Name Of Error Code    Reasons/Problems    Solutions
Error Code-15The heat exchanger has been maintaining continuously 207 Degrees temperature for 15 seconds and ultimately it creates pressure on breakers to trip repeatedly.Turn off the electric panel and check the heat exchanger thermistor and Reset the units.
Error Code-16Over Temperature Warning. Indicating the temp is above the remote thermostat setting. And this high heat badly impacted Circuit breakers.Check the heat exchanger thermistor and outlet thermistor. Clean the fans on the heat exchanger and set your desired temp.

How To Reset The Breakers Of Your Rheem Tankless Water Heater

Though there are some common reasons for your Rheem tankless water heater circuit breaker tripping. You can simply fix most of the issues by resetting the units before replacing any parts.

In most cases, reset processing is very efficient for solving your heater’s circuit problems. The steps will save you money and time. Let’s learn how to reset it.

  • After finishing the breaker to know if it got tripped, it is now time for the unit to reset.
  • To reset a breaker, keep all the switches in the OFF position.
  • When you turn the switches back on, you will hear a few beeps or a similar sound.
  • Just find the Red Reset Button and press it, then hold the reset button for 3-5 seconds.

Finally, your circuit breakers will be ready to start again.


How do my Rheem tankless water heater’s circuit breakers work?

The circuit breakers are the resettable fuses that automatically operate the electrical switches and cut off the circuit when the power crosses the safety limit or level. Actually, the breakers help to prevent electrocutions.

What is the ideal size breaker needed for a Rheem tankless water heater?

Your Rheem tankless water heater requires a 40 AMP breaker, including the dimensions of 10″ x 7″ (high & wide). It should be 3–4″ deep. It also requires 120 AMPs to run on average.

What happens if I ignore or go unnoticed when my breakers trip?

Your breaker is tripping, which means too much power is trying to pass through the circuit at once. This can overheat the electric wiring, which may damage the circuit board or the entire electric system of the heater. Finally, a sudden fire or electrocution may occur.


We have already identified the reasons why your Rheem tankless water heater breaker is tripping and outlined their simple solutions. So, follow our troubleshooting guide to fix your tankless water heater’s breaker troubles as guided in this article.

Remember to stay safe unless you are experienced with electrical issues. Call a licensed electrician to repair or replace your Rheem tankless water heater’s circuit breaker.

Yet, if you have any queries about your water heater breakers problems, don’t hesitate to reach out to us with your comments. We will reach out to you ASAP with an easy solution.

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