Rinnai Tankless water heater reset button [How to reset]

In this article, we will help to know the location of the Rinnai tankless water heater reset button, how to reset Rinnai tankless water heater, and how to master or hard reset the Rinnai water heater in simple and easy steps. This guide of Rinnai heater reset will help you reset error codes, LC codes, and other problems.

Rinnai tankless water heaters are known for their reliability, durability, and safety. Still, even the best appliances may encounter troubles occasionally and need to be fixed.

Rinnai water heaters are equipped with good safety mechanisms that detect faults and display them as error codes to understand the issue. However, some errors like maintenance can be skipped for some time by resetting the tankless water heater.

Sometimes, the error code is displayed even after fixing the issue, which needs a reset function to make the heater work again. Power outages and surges are common culprits that require resetting your Rinnai tankless water heater.

Rinnai tankless water heater reset button location

The location of the reset button on a Rinnai tankless water heater can vary depending on the specific model and design. However, there are some general guidelines to help you find it:

  1. Front Panel controller : In many Rinnai tankless water heaters, the reset button is located on the front panel controller. Yes, it is on the frontpanel controller, it is not mentioned as Reset button, the ON/OFF button works as the reset button to quick reset the rinnai tankless water heater.
  2. Reset button on outdoor units: Outdoor models doesn’t has controller on the front panel, but it is inside the unit which can be accessed by removing the front panel where you can find the ON/OFF button. Some units have an external remote controller on which you can find ON/OFF button to reset the water heater. Refer to your unit’s manual for instructions on accessing and using the control panel.
  3. Hard reset button: To hard reset the rinnai water heater there are two button located on the internal PC Board A and B, top is A and bottom button is B. These are the hard reset buttons to clear the error codes when the normal reset buttons doesnt work for some fixes like resetting LC codes.
  4. Consult the Manual: The best way to pinpoint the exact location of the reset button for your specific Rinnai tankless water heater is to refer to the manufacturer’s manual that came with the unit. The manual will provide detailed instructions and illustrations specific to your model.

How to reset Rinnai tankless water heater

Resetting your Rinnai tankless water heater can be a simple task. It’s quite straightforward. In the below steps, we’ll guide you through two easy methods (normal reset and hard reset) to reset your Rinnai tankless water heater when needed.

Method 1: Normal reset using ON/OFF button

locating the temperature controller and it buttons of rinnai tankless water heater

As we already know the location of the reset button (ON/OFF) which is on the front panel controller, or inside the front panel for outdoor units. We need to press the ON/OFF button five times in the span of five seconds. By pressing it the Rinnai tankless water heater performs reset operation and clear the error codes.

This method works for few errors only and to skip some error codes for some time limit without stopping the water heater operation.

Method 2: Hard reset using A and B buttons on PCB

hard reset buttons of rinnai tankless water heater

Sometimes, your Rinnai tankless water heater may require a master reset to restore it to its optimal performance and to clear the error codes or other issues. Below steps will help you to perform a master reset of your Rinnai tankless water heater effectively.

Step 1: Locate Buttons A and B

Begin by identifying buttons A and B on your Rinnai tankless water heater’s PC board or PCB . These buttons are black in color and located on right side of the board.

Step 2: Press and Hold A and B (P Appears)

Press and hold both buttons, A and B, simultaneously for approximately 10 seconds. During this time, the letter “P” appears on the display. Continue holding the buttons until you see this “P” indicator.

Step 3: Press and Hold A and B (PLC Appears)

Once you see “P” on the display, continue pressing and holding buttons A and B for another approximately 10 seconds. Now, you will observe “PLC” appearing on the display.

Step 4: The Unit Powers Off

After “PLC” appears on the display, your Rinnai tankless water heater will automatically power off. This signifies that the master reset process is in progress.

Step 5: Power the Unit Back On

Now, it’s time to power your Rinnai tankless water heater back on. Press and hold the power button(ON/OFF) until you see the unit initiating the startup process.

Step 6: Monitor for Normal Operation

As your Rinnai tankless water heater powers up, monitor it closely for normal operation. Ensure that there are no error messages displayed and that it functions as expected.

How to reset a Rinnai tankless water heater after descaling

After descaling or Rinnai tankless water heater maintenace, we need to perform the master reset by following the above steps, Normal reset doesnt work as the error code will return in 70 hours.

Helpful article: Rinnai tankless water heater No hot water

When to Seek Professional Help

While resetting your Rinnai tankless water heater can resolve many issues, some problems may require professional assistance. Consider reaching out to a technician or plumber if:

  • The error code persists after resetting.
  • You are uncomfortable with the reset process or accessing internal components.
  • You suspect a more significant issue with your water heater.

Joseph Miller

Joseph Miller is a highly experienced water heater repair expert with a passion for keeping homes warm and comfortable. With over 50 years of industry expertise, Joseph has developed a deep understanding of water heater systems and the intricacies of their repair and maintenance.

Related Articles


  1. Hi Sir,
    I have recirculationnpum with a dedicated return line. I have been trying to change the setting to 4b but button A on the right side on plc not allow me. I pressed for 3 secs nothing came up. Please help!
    Thank you

  2. Do you have any info on how to activate/program/utilize the recirculate feature on a Rinnai RU 199iP??

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button