How to Reset a Rinnai Tankless Water Heater: All Models Guide

Quick Answer

Rinnai tankless water heaters support three levels of reset. A soft reset is done by pressing the power button on the controller to turn the unit off, then pressing it again to turn it back on. A hard reset cuts power at the circuit breaker for 30 seconds. A factory reset on the MC-91-2 or similar controllers is performed by pressing and holding the Mode and Set buttons simultaneously for 5 seconds. Resetting without fixing the underlying fault will only temporarily clear the code; it will return on the next heating demand if the root cause is still present. The most reset-responsive codes are 11, 12, and 10 after a transient gas interruption.

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How to Reset Your Rinnai Waterheater

Three reset methods for Rinnai units: power button (soft), breaker cut (hard), and Mode+Set hold (factory). Resetting without fixing the cause will not resolve the fault.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Error code appears after a transient gas pressure fluctuation40%

Code triggered by a brief power surge or outage24%

Unit needs reset after a repair is completed14%

User wants to verify whether a code was persistent or one-time12%

Error code from an isolated event that has self-resolved10%

Symptoms You May Notice

Error code displayed on controller that may be transient
Unit stopped working after a brief power interruption
Unit stopped after gas work was performed nearby
Repair just completed and unit needs to be restarted
User wants to confirm whether the error is persistent

Tools Required for Diagnosis

None required for soft or hard resetScrewdriver (if breaker panel needs a tool to access)

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

Identify the error code displayed before attempting any reset

Identify the error code displayed before attempting any reset. Write it down. If the code is 10, 11, or 12 after a known gas interruption or power event, a soft reset is appropriate as the first step.

Perform a soft reset

If the soft reset did not resolve the issue, perform a hard reset

To perform a factory reset on models with the MC-91-2 or similar

After any reset

Frequently Asked Questions

Where is the reset button on a Rinnai tankless water heater?

Rinnai tankless water heaters do not have a dedicated reset button. The reset is performed using the power button on the controller: press it to turn the unit off, wait 10 seconds, then press it again to turn it on. This is the soft reset. For a hard reset, use the circuit breaker for the unit. There is no separate red or yellow reset button as found on some other appliances.

How many times can I reset a Rinnai before I need to call a technician?

If an error code returns more than twice after resetting, stop resetting and diagnose the root cause. Repeated resets without repair can mask a worsening component failure and, for gas-related codes, repeated ignition attempts with a fault present carry a safety risk. One or two resets to confirm whether a fault is persistent versus transient is reasonable.

Will a factory reset delete my temperature settings on a Rinnai?

Yes. A factory reset restores the controller to its default temperature settings, which is typically 120F on most Rinnai models. After a factory reset, re-enter your preferred hot water temperature using the Up and Down buttons on the controller. Your temperature setting was the only user-configurable parameter that will be lost; the unit's operating firmware is not affected.

Can I reset a Rinnai remotely using the app?

Models compatible with the Rinnai Control-R Wi-Fi module allow remote temperature adjustments through the Control-R app but do not currently support remote error code clearing. A physical reset at the controller or circuit breaker is required to clear an error code.

My Rinnai reset itself during the night and lost my temperature setting. Is this normal?

A spontaneous reset overnight usually indicates a brief power interruption, even one short enough not to trip other devices or be noticed. The unit's PCB will revert to default settings after losing power. If this happens repeatedly, check for loose wiring in the electrical panel or at the unit's power connection. A UPS (uninterruptible power supply) on the unit can prevent spurious resets if power quality is an issue.

Related Rinnai Waterheater Error Codes

Code: HUBRinnai Tankless Water Heater Error Codes: Complete Guide Code: 11Rinnai Code 11: No Ignition Fix for RU and V Series Tankless Heaters Code: 12Rinnai Code 12: Flame Failure During Operation Code: 10Rinnai Code 10: No Gas Supply or Gas Valve Failure

Same Fix on Other Brands

Navien waterheaterHow to Reset a Navien Tankless Water Heater and Clear Error Codes

Models Known to Experience RESET Errors

This repair applies to most Rinnai waterheaters with this error code. Common model numbers include:

RUR98iN, RU199iN, RU98eN, V65iN, RL75iN, RU160iP

Last verified for technical accuracy on March 14, 2026