How To Reset A Rinnai Tankless Water Heater?

Resetting a Rinnai Tankless Water Heater is a simple process that can be done by following a few steps. First, Your Rinnai Tankless Water Heater should now be reset and ready to use. Remember to always consult your owner’s manual for specific instructions and safety precautions.

Imagine coming home after a long day, looking forward to a relaxing hot shower, only to find that your water heater is not working. It’s a scenario that can send chills down anyone’s spine. But don’t worry, resetting your Rinnai tankless water heater can often solve the problem and get you back to your comforting routine.

In the following sections, we will guide you through the steps to reset your Rinnai tankless water heater. This process is relatively straightforward and can be done without the need for professional help. However, it’s important to follow the instructions carefully to ensure the safety and longevity of your water heater.

Understanding Rinnai Tankless Water Heaters

How tankless water heaters work

Rinnai tankless water heaters are a marvel of modern technology. They work on a simple principle: heating water only when you need it. Unlike traditional tank-style water heaters that continuously heat and store water, tankless units remain dormant until you turn on a hot water tap. 

When you do, cold water travels through a pipe into the unit, where either a gas burner or electric element heats it instantaneously. As a result, you get a consistent flow of hot water on demand, without the energy losses associated with maintaining a hot water tank.

Rinnai’s tankless water heaters are known for their high efficiency. They operate with impressive energy savings, which is not only eco-friendly but also reduces your utility bills. Additionally, they are space efficient, as they don’t require a bulky storage tank, making them a great choice for homes with limited space.

When to Reset Your Rinnai Tankless Water Heater

Common scenarios that require a reset

If you are experiencing any issues with your Rinnai tankless water heater, such as error codes, lack of hot water, or power disruptions, you may need to reset the unit. To reset the water heater, locate the reset button on the unit and press it. This should help resolve any minor issues and restore normal operation.

  • Error Codes: Rinnai tankless water heaters are equipped with advanced diagnostic systems that may display error codes to alert you to specific problems. If you see an error code on the unit, it’s usually a sign that a reset may help clear the issue. 
  • No Hot Water: When your tankless water heater suddenly stops delivering hot water, and you’ve confirmed that other factors like gas or power supply are not the issue, a reset may be in order.
  • Power Interruptions: Sometimes, power interruptions or surges can cause the tankless water heater to behave erratically. Resetting the unit can help restore normal operation.

Troubleshooting before resetting

Before jumping to reset your Rinnai tankless water heater, it’s advisable to perform some troubleshooting. Sometimes, the issue might be a minor hiccup that doesn’t require a full reset:

  • Check Gas Supply: If you have a gas-powered unit, ensure that the gas supply is not interrupted. Sometimes, a simple issue like a closed gas valve can lead to a lack of hot water.
  • Inspect Power Supply: For electric models, verify that the unit is receiving power. A tripped circuit breaker or a disconnected power cord might be the cause of the problem.
  • Water Flow: Confirm that there is an adequate water flow through the unit. Low water flow can lead to improper heating and may mimic a heater malfunction.

Safety Instructions

Before attempting to reset your Rinnai tankless water heater, always prioritize safety. Turn off the power and disconnect the unit properly. Allow the heater to sit idle for a few minutes to dissipate residual power. Following these safety instructions is essential to avoid accidents during the reset process

StepbyStep Reset Process

 Disconnect the Tankless Water Heater

  • Safety first! Ensure that the power supply to the water heater is turned off. If it’s a gas heater, also turn off the gas supply. This will prevent any accidental injuries or damage to the unit.

Find and Remove the Cover Plate

  • The cover plate is usually located on the front of the unit. It protects the internal components of the heater. Remove the screws holding it in place and carefully take it off. Remember to keep the screws in a safe place for reassembly.

Take Out Insulation

  • Behind the cover plate, you’ll find insulation protecting the internal components of the heater. Carefully remove this insulation, making sure not to damage it. It’s essential to remember how it was placed so you can put it back correctly.

Locate the Reset Button

  • The reset button is typically a red or black button located on the water heater’s thermostat. It’s a small but crucial component that can help resolve many common issues with the heater.

Ensure the Tankless Water Heater is in Reset Mode

  • Press the reset button. You should feel it click, indicating that the water heater is now in reset mode. This mode allows the heater to recalibrate and resolve any minor issues.

Change the Thermostat

  • If your water heater has a digital thermostat, adjust the temperature to the desired level using the buttons or dial on the unit. If it’s a dial-type thermostat, gently turn the dial to the desired temperature.

Check for Power Outages in the Home

  • Before turning the power back on, make sure there are no power outages in your home that could affect the operation of the water heater. If there are, wait until the power is restored before turning the heater back on.

Waiting for a few minutes

  • After powering off the unit, you must be patient. Waiting for a few minutes is crucial because it allows any residual power or heat to dissipate entirely. This ensures that the unit starts fresh when you power it on again.

After following these steps, your tankless water heater should be reset and ready to use. If the problem persists, it’s best to contact a professional for further assistance. Remember, safety should always be your top priority when dealing with appliances. Always follow the manufacturer’s instructions and guidelines.

Here’s a table summarizing the key points of the article “How To Reset A Rinnai Tankless Water Heater,” along with a conclusion, safety instructions, and a meta description:

SectionKey Points and Descriptions
IntroductionDefinition: Explains what a Rinnai tankless water heater is and the need for resetting it.
Interesting Hook: Paints a scenario of cold showers to capture the reader’s attention.
FAQs addressing reset frequency, remote resetting, failure of reset, long-term maintenance, and resetting error codes.
Understanding Rinnai Tankless Water HeatersHow tankless water heaters work and their advantages.
When to Reset Your Rinnai Tankless Water HeaterCommon scenarios requiring a reset and the importance of troubleshooting.
StepbyStep Reset ProcessDetailed instructions for safely resetting a Rinnai tankless water heater.
FAQsFAQs addressing reset frequency, remote resetting, failure of reset, longterm maintenance, and resetting error codes.
ConclusionRecap of the importance of resetting and maintaining Rinnai tankless water heaters for a constant hot water supply.
Safety InstructionsEmphasizes safety when resetting, including turning off power and proper waiting time.
Meta DescriptionLearn how to reset your Rinnai tankless water heater efficiently to enjoy uninterrupted hot water. Safety tips included.



A tankless water heater is a valuable investment that provides numerous benefits, including energy efficiency and an endless hot water supply. Regular maintenance, including resetting the unit when necessary, can extend its lifespan and ensure it continues to function efficiently.

Lastly, while resetting the unit can solve many issues, some problems may require professional intervention. If your water heater continues to malfunction after a reset, it’s best to contact a professional technician.

They have the necessary training and experience to diagnose and repair more complex issues, ensuring your water heater remains in good working condition for years to come.

Leave a Comment