Rinnai Tankless Water Heater Beeping—What’s Wrong?

With a Rinnai tankless water heater, homeowners and guests can enjoy hot water whenever needed. Although this plumbing fixture works well most of the time, it may sound its alarm during certain scenarios. But what could be the problem when a Rinnai tankless water heater’s alarm is beeping? We researched for you and found this answer.

A Rinnai tankless water heater’s alarm can beep continuously when it encounters errors. Some of these potential faults include error codes 2 through 79. Certain events may also cause the unit's display to show error codes accompanied by other letters instead of numbers. One example is Error Code LC0, which means the water heater found limescale buildup.

Verifying the cause of the error prevents users from making mistakes during troubleshooting. Keep reading as we talk about these error codes in more detail. We’ll also discuss how to troubleshoot a Rinnai tankless water heater if it shows specific errors.

House heating concept, modern home gas fired boiler. Rinnai Tankless Water Heater Beeping—What's Wrong

Why Is My Rinnai Tankless Water Heater Beeping?

A Rinnai tankless water heater can trigger its alarm when it encounters different errors. Some of these error codes and their meanings are:

  • Error Code 02: Water heater not working while in freeze protection mode.
  • Error Code 05: Malfunction at the bypass servo.
  • Error Code 10: Exhaust or air supply clog.
  • Error Code 11: Water heater cannot ignite.
  • Error Code 31: Abnormality detected in the burner sensor.

Water heater hanging on the wall

Understanding these error codes allows Rinnai water heater owners to verify specific problems. In turn, users can apply the correct course of action to troubleshoot, repair, or replace particular parts.

Additionally, some error codes, such as Error Code 30, which means the fixture detected flammable vapors, typically demand expert troubleshooting and repair. DIY beginners shouldn't attempt to fix these concerns, for these additional mishaps may lead to health hazards to their well-being or permanent damage to the unit.

What Is A Rinnai Tankless Water Heater Error Code LC0?

An Error Code LC0 (up to LC9) flashing on a Rinnai tankless water heater’s display typically means the fixture detected limescale buildup. Owners should refer to the product’s instruction manual to remove this substance and restore serviceability to the unit.

hand rotate temperature adjuster of water heater

How To Troubleshoot Rinnai Tankless Water Heater?

The troubleshooting steps required to shut off a Rinnai tankless water heater's alarm depend on the error code and the specific problem encountered. For example, Code 03, which means that the water heater met a malfunction as the fixture is trying to fill up a bath when a power outage occurred, may only require users to press the ON/OFF button twice to reset the system.

On the other hand, faults like Error Code 10 typically demand additional steps to turn off the beeping and restore proper functionality to the fixture.

Here’s a look at how you can troubleshoot the exhaust or air supply blockage that triggered Error Code 10 in a Rinnai water heater:

Step-by-Step Guide

  1. Remove the vent from the top of the Rinnai tankless water heater. Then, inspect if the unit can turn on even without the vent. If so, the problem often lies in the vent pipe installation.
  2. Proceed with the troubleshooting by checking each vent section. Ensure that each component has a proper attachment and installation depth.
  3. Inspect each clearance. Improper clearance installation can result in combustible gases recirculating within the water heater.
  4. Check the dip switch and ensure it’s at the proper position. This component should be at a 90-degree angle elbow for each count of the vent’s length.
  5. Verify the presence of debris stuck in the vent system. If so, remove these substances that might otherwise cause the error code.
  6. Ensure that the vent terminals have the correct clearance distance from grade, overhangs, obstructions, and other objects.

Keep in mind that blockage to the tankless water heater's air supply or exhaust may not be the main reason the fixture's alarm triggered. Even if the unit is displaying Error Code 10, it may also mean that it has a bad fan motor, a faulty wiring harness, or a short-circuited PC board.

You might also come across some malfunctions with your home’s furnace. If so, read our post on what to do if a furnace clicks but its blower doesn’t start to find helpful troubleshooting steps.

hand turning knobs of water heater at home

How To Reset Rinnai Tankless Water Heater?

Resetting a Rinnai tankless water heater may help turn off its incessant beeping, particularly when it encounters error codes like Error Code 03. The steps to soft resetting this water-heating system are:

  1. Turn off all water fixtures, such as bathtubs and faucets, connected to the water heater.
  2. Press the ON/OFF button twice.
  3. Turn the hot water on from the water heater to test.

Bear in mind that resetting a Rinnai tankless water heater may take a few tries before the process provides successful results.

How To Fix Rinnai Tankless Water Heater Beeping With No Error Code?

If a Rinnai tankless water heater doesn’t display an error code, its alarm is beeping, and it’s not functioning, you can start the repair by unplugging and plugging the fixture from and to its connected power source.

But if power cycling the fixture doesn’t fix the problem, continue with the troubleshooting and repair by following these steps:

  1. Turn off the cold water but leave the hot water open.
  2. Drain the hot water from the system. Then, remove the plug above the cold water valve.
  3. Clean the screen being covered by the plug.
  4. If the unit still fails to function upon reaching this step, repeat steps 1 to 3. But this time, drain the cold water as well.
  5. Set the cold and hot water to the on position. Test the fixture by restoring power to it and checking if the problem persists.

At this point, the issue may not go away. If so, you can continue attempting to restore serviceability to the Rinnai water heater. However, this time you’re going to need an air compressor. Once you have that piece of equipment, here are the steps to use it to help fix the plumbing fixture:

  1. Ensure that the cold and hot water is off and the tanks in the fixture are empty.
  2. Remove the bolts from the plate above the cold water valve. Set the plate aside once it’s loose.
  3. Spray the inside of the water heater through the hole with the air compressor. You’ll know if it’s working if a whirring sound appears.
  4. Cover the hole with the plate again and secure it with its bolts.
  5. Test the fixture to see if the beeping stopped and if the functionality returned.

Check out this air compressor on Amazon.

Find out more details about these methods by watching the video below:

At this point, if the Rinnai water heater still doesn’t work, it might be best to contact the manufacturer or a certified technician to help with the repairs.

What Temperature Should Rinnai Be Set At?

The temperature of a Rinnai tankless water heater should be at 120 degrees Fahrenheit to avoid bathwater becoming scalding. However, some users can increase the temperature up to 140 degrees Fahrenheit if desired. Use the following steps to complete this task:

  1. Disconnect the water heater from its power source.
  2. Unscrew the front cover.
  3. Find the dip switch number 6 and set it to the on position. A small screwdriver might be necessary for this step.
  4. Return and secure the front cover. Then, restore power to the water heater.

Users should keep in mind that bathing in hot water for extended periods can cause health issues. Some of these risks include dry skin and lowered immune system. Additionally, it’s wise to only run a water heater an average of 3 to 5 hours per day. Find out more about a typical water heater usage by reading our post on that subject matter.

How Long Is The Warranty On A Rinnai Tankless Water Heater?

Rinnai offers different warranties for their tankless water heater models. The coverage period for these fixtures typically depends on the application.

The following is a short list of warranty periods based on the application declared for the purchased Rinnai tankless water heater:

  • Residential application: 12 years
  • Residential and space heating applications: 10 years
  • Commercial applications: 5 years

Moreover, the brand offers a 5-year warranty for all parts and components aside from the heat exchanger. Interested customers should also know that the warranty period begins upon the purchase date and not from the manufacturing date.

Worker set up central gas heating boiler at home. Rinnai Tankless Water Heater Beeping—What's Wrong

Final Words

Errors are generally the culprits why Rinnai tankless water heaters beep persistently. The error codes displayed on the screens of these plumbing fixtures should show the sources of these problems. Applying the correct techniques to troubleshoot and repair can help owners restore proper serviceability to these water-heating systems.

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