Welcome to our ultimate guide on the Rinnai Tankless Water Heater Reset Button. If you’ve ever wondered how to reset your Rinnai tankless hot water heater or whether it even has a reset button, you’ve come to the right place. We’ll provide clear instructions to get your hot water flowing again. 

Before we begin, it’s important to note that the methods we’ll discuss have been tested on the RL75 model. However, they are also expected to work for other Rinnai tankless water heater models.

Is there a reset button on a Rinnai Tankless Water Heater?

The short answer is no, it doesn’t. We looked carefully in the manual but found no information about a reset button.

But don’t worry. You can still reset your Rinnai tankless water heater. Here’s how:

How To Reset Rinnai Tankless Water Heater?

This section shows you how to make your Rinnai tankless water heater reset again if it stops giving you hot water.

Method 1: Use the On/Off Button:

This method uses the On/Off button to reset your Rinnai tankless water heater. Here’s how to do it:

1. Locate the On/Off Button:

 Find the On/Off button on your Rinnai tankless water heater. It’s usually on the temperature controller, like your water heater’s control panel. Think of this button as the ‘power’ button that starts or stops your water heater.

2. Press It Five Times Quickly:

 Now, press the On/Off button five times in a row, and do it within 5 seconds. It’s like clicking the power button on your TV remote five times quickly, almost like a secret code. 

3. Wait for Reset:

 After pressing the button five times, wait a moment. Your water heater will do some behind-the-scenes work, and it will reset itself. 

4. Check for Error Message:

 If your water heater shows an error message, it should disappear after the reset.

This method works when your water heater displays a specific error code. By pressing the On/Off button five times quickly, you’re telling your water heater to clear that message and start fresh.

After performing this method, your Rinnai tankless water heater reset should be back to normal, providing you with hot water as it should. If the error persists, try the other methods described in the next part of the blog or seek assistance from a professional.

Method 2: Activating the A and B Buttons

1. Remove the Front Panel: 

You need to remove the front panel and take it off to access the A and B buttons. Find the four nuts holding the front panel in place to do this.

2. Locate the A and B Buttons

 Once you’ve removed the front panel, you’ll see the inner workings of your water heater. Look for the A and B buttons; they might look like small switches or controls.

3. Press and Hold Both Buttons:

 Now, it’s time to press and hold the A and B buttons simultaneously. Press them down together and save them for about five to eight seconds.

What to Do if Something Different Happens on the Display:

Sometimes, when you press the A and B buttons, the display on your water heater might show the letter ‘P.’

  • If ‘P’ Appears: If you see ‘P’ on the display, your water heater is in a different mode. Press and hold both the A and B buttons again and the presentation should change to ‘PCL.’ 

After you’ve done this, your water heater should reset and work properly again. If it still doesn’t function, you can attempt a different approach.

Additional Resetting Methods

If the methods mentioned earlier didn’t work to reset your Rinnai tankless water heater, here’s another way you can try:

Method 3: Check the Circuit Breaker or Power Supply:

1. Locate Your Circuit Breaker Box: 

First, locate the place in your home where the circuit breaker or fuse box is. It’s like the control center for all the electricity in your house.

2. Check for Tripped Breakers or Blown Fuses:

 Open the circuit breaker box and look for any switches in the “off” position or fuses that look burnt out or broken.

3. Reset the Breaker or Replace the Fuse: 

If you see a switch in the “off” position, flip it to the “on” position. If you discover a blown fuse, swap it out with a new one that matches the same type. 

4. Turn on the Water Heater: 

After checking and fixing any circuit breaker or fuse issues, please return to your Rinnai tankless water heater and try turning it on again using method 2.

This method is like ensuring your water heater has the electricity to work correctly. Sometimes, a tripped breaker or blown fuse can be why your water heater isn’t functioning, so checking and fixing this can be an essential step in getting it back up and running.


 Rinnai tankless water heater reset is a relatively straightforward process. If you follow the steps outlined in this blog post, you should be able to get your hot water flowing again in no time. If you find yourself without hot water, following these steps can save you from the inconvenience of a malfunctioning water heater. We hope this guide has helped you learn how to reset your Rinnai tankless water heater. If you’ve tried all the methods above and your water heater is still not working, it’s best to call a qualified technician to diagnose and fix the problem.

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