A Rinnai tankless water heater is a highly efficient and space-saving appliance that provides hot water on demand. Unlike traditional tank-style water heaters, Rinnai units heat water only when it is needed, which means they use less energy and take up less space in your home.

These units come equipped with advanced technology that can help conserve energy and reduce utility costs. Even though Rinnai tankless water heaters are built to last for many years, there may be instances where you need to reset the unit to restore optimal functionality.

Several factors can cause your Rinnai tankless water heater to malfunction; for instance, power outages or voltage fluctuations may cause the system to shut down unexpectedly. Furthermore, if you notice your unit isn’t producing hot water satisfactorily or is displaying error codes on the control panel, resetting it may resolve the issue.

Steps for Resetting a Rinnai Tankless Water Heater

Step 1: Turn off power and gas supply to the unit.

The first step in resetting your Rinnai tankless water heater is to turn off both the power and gas supply. On your electric panel flip the break that powers your hot water heater to the “off” position. For the gas supply, find the valve on the supply line (this should be close to the unit) and turn it off.

Step 2: Locate the reset button on the control panel.

After shutting off the power and gas supply, find the reset button on the control panel of your Rinnai tankless water heater. Refer to your owner’s manual to determine its specific location. Typically, the button is labeled as “reset.”

Step 3: Press and hold down the reset button for 5 seconds.

Once you’ve located the reset button, press it and hold it down for 5 seconds. You should feel a click as you press it. Continue holding it until all lights on the control panel are completely turned off.

Step 4: Release the button when all lights on the control panel turn off.

When all the lights on the control panel have turned off entirely, release the reset button.

Step 5: Turn on power and gas supply to the unit.

After releasing the reset button, it’s time to restore power and gas supply to the unit. First, turn on the electrical power supply switch. Then, open the gas valve by rotating the knob clockwise. Remember to wait for at least 10 minutes before turning on the power and gas supply to ensure proper functionality of the water heater.

Step 6: Wait for 10 minutes for the unit to heat up.

Allow your Rinnai tankless water heater at least 10 minutes to heat up after turning on the power and gas supply. This waiting period will allow the system to reset and stabilize, ensuring the prompt availability of hot water.

Step 7: Test your hot water.

After the 10-minute waiting period, test your hot water by running taps in your home. If everything goes well, you should now have hot water flowing again!

Troubleshooting Tips

While resetting a Rinnai tankless water heater can often fix issues, sometimes there may be more complex problems that require further troubleshooting. Here are some tips for readers who may encounter issues during or after resetting their Rinnai tankless water heater:

Error codes after resetting a rinnai

When a reset is performed on a Rinnai tankless water heater, it’s not uncommon to encounter an error code on the control panel. This error code usually indicates the underlying issue that led to the need for a reset. However, it is now much easier to troubleshoot the issue.

The common error codes you may encounter after a reset as follows:

  1. Error Code 10 (no combustion): This code indicates a problem with the combustion process. To resolve this issue, you can refer to the article Rinnai Error Code 10 for detailed troubleshooting steps.
  2. Error Code 11 (no ignition): If you see this error code, it means that the heater is having trouble igniting the flame. To address this issue, please refer to the article Rinnai Error Code 11 for comprehensive instructions on resolving Error Code 11.
  3. Error Code 12 (flame failure): When Error Code 12 appears, it signifies a failure in maintaining the flame. You can find guidance on resolving this problem in the article Rinnai Error Code 12, which provides step-by-step solutions.

By referring to these articles specific to each error code, you can gain a better understanding of the issue and effectively troubleshoot your Rinnai tankless water heater.

Rinnai Tankless Water Heater Leaking

When tackling leaks in or around your Rinnai tankless water heater after a reset, remember a few key steps. Leaks can be caused by various factors like loose connections, damaged pipes, or worn-out fittings. Begin with a thorough visual inspection, examining each pipe and connection for signs of moisture or dampness.

  1. For leaks on threaded connections, undo them, replace the Teflon tape, and rethread the connections for a tighter seal and prevention of future leaks.
  2. If you find a leak from a soldered joint on copper pipes, call a professional plumber. Soldering copper requires specialized skills, and it’s best to have a professional handle the repair or provide guidance.
  3. If there’s a leak in a PEX connection, remove the connection and create a new one with a fresh ring for a secure and leak-free connection. If it’s a shark bite fitting, replace it with a compression fitting.
  4. If the leak originates from the manifold and your hot water heater froze with water in the lines, you may need to replace either the manifold or the entire unit, depending on the extent of the damage.

While a reset often solves common issues, depressurizing it for a short time can cause some small leaks to show up out of the blue. If this happens you can always call a professional to bail you out.


If you encounter any issues during or after resetting your Rinnai tankless water heater, refer to our troubleshooting tips section in this article or consult a professional for assistance. Remember that regular maintenance can help prevent issues with your unit from occurring in the first place.

Resetting a Rinnai tankless water heater is an easy task that can save you time and money in case of any problems with your unit. With proper care and maintenance, your Rinnai tankless water heater will continue to provide hot water efficiently and reliably for years to come.