Tankless water heaters are known for their instant hot water supply and long life. Sometimes, there will be interruptions in continuous supply. Here’s how you can quickly reset them in such a scenario.

Find the reset button on the tankless water heater. It is often RED and located behind the metal panel, which is removable. In some units, it may be located near the thermostat. Press the reset button and then release it after hearing the click sound.

This article will provide you with complete step-by-step information on “How to troubleshoot a tankless water heater?” We will also cover;

  • Where is the reset button located on the tankless water heating unit?
  • How long do you need to press the troubleshooting button?
  • When to reset it?
  • Common Error Codes 
  • Why does your heating unit trip?

How to Reset a Tankless Water Heater?

To reboot your tankless water heater, all you need to do is follow “Three Simple Steps.”

  1. Find the red button on your heating unit.
  2. Push it for almost 5 seconds.
  3. Release it.

There is no hard rule for resetting a tankless heating unit.

How Can I Reset My Electric Tankless Water Heater?

Troubleshoot your electric unit by following these six easy steps. It is always advised to cut the power supply before touching any electric appliance.

  1. Turn the breaker off.
  2. Locate the “raised panels.” Commonly, there are two panels on the electric unit. 
  3. Once you open the “upper panel,” you’ll find covered insulation to keep the moisture away.
  4. Under the insulation sheet, there is a reboot button. Usually, the color of the switch is red. Sometimes the button color is black.
  5. Push the button and screw back the raised panel to its actual shape.
  6. Turn the breaker on.

Why my electric tankless water heater is often tripping? 

 You need to restart or reset your water heater due to;

  • Power Surge.
  • Moisture in Panel.
  • Broken or Worn Out Heating Element.
  • Breaker Issue.
  • Overloading or Overusing.

If you notice tripping often, consider getting some professional help then.

How Can I Reset Your Rinnai Tankless Water Heater Anual Descaling?

After descaling, here’s your quick guide to factory reset the Rinnai tankless water heating unit.

  1. Find the “Connect” button on the module.
  2. Press and hold it.
  3. Wait for the LED blink red and white.
  4. Once you notice the clour changing, release it.
  5. Quickly tap three times.

This will restore the setting to its original factory settings.

Finding the Button.

To reboot the tankless water heater, you need to “press the button”! Sounds easy. But if you are searching for “Where is the red button located,” we got you!

Where is the reset button located on the tankless water heater unit?

The red button is located behind the “upraised panel in the tankless water heating units.” To find the factory reboot button, you may need to remove the panel.

How Long Do You Need to Press the Red Reset Button on Tankless Water Heater?

To troubleshoot your heating unit back to factory settings, press the button for 3 to 5 seconds. It is not recommended to hold the button for too long.

Troubleshooting The Tankless Water Heater – Find Your Unit Brand

1. Takagi Tankless Water Heater.

Some of the common errors in these specific branded heating units are;

  • Error Code 661: Issue with bypass valve
  • Error Code 761: Water temperature is over 104°F

How can you reset your Takagi tankless water heater?

Troubleshoot your unit easily and quickly by following these steps.

  1. Cut the power. (This step is advised as a safety precaution)
  2. Remove the front cover.
  3. Hold and press the dip button 1 & 2 for 3 seconds.
  4. Turn on your unit and enjoy a non-stop supply of hot water.

2. Rinnai Tankless Water Heater.

Rinnai is a trusted brand by millions when it comes to home appliances. Its unit’s display errors start from 02 to 79, including no error code per user manual.

How can I reset my Rinnai tankless water heater without any professional help?

Here’s how you can quickly reboot your Rinnai unit at home.

1. Look for the connect button.
2. Hold it for 5 seconds.
3. Once you notice that the LED light blinks to white, release it.

Doing this will shift the module back to the factory settings.

3. Rheem Tankless Water Heater.

Rheem has a manual that displays every error code with a complete description. If you need to reboot it, follow these steps.

  1. Disconnect the circuit by turning it off.
  2. Take off the panel cover and find the reset button.
  3. Press the button inwardly.
  4. Release it once you hear the “click” sound.
  5. Put back the panel safety cover and turn on the circuit.

4. Noritz Tankless Water Heater.

Noritz is second to none when it comes to compatibility. They are capable of beige controlled by remote. There is always a “two-digit” error code displaying the problem. To reboot your Noritz unit, all you need to do is “press the reset button.”

5. Marey Tankless Water Heater.

Marey is a trusted brand because its heating unit often doesn’t cause any problems. Most of the issues people face are either the system won’t start, or there is no click sound when they reboot it.

Marey’s user manual has a complete guide with solutions to its error codes. If you are looking for the answer to “How to reset tankless heater by Marey?” then all you need to do is hit the reset button.


After years in the water heaters and plumbing industry, I can conclude that most tankless hesitating unit trips because the thermostat is not working correctly. To reset your heating unit, you need to hit the “Red Reboot Button” located inside the panel.


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