My Rinnai Recirculation Is Not Working – Why? What To Do?

A tankless water heater such as the Rinnai Recirculation is a great thing to have at home. But if it suddenly stops working, you'll be wondering what's wrong. We did the research and found answers, so you know what's going on if your Rinnai water heater stops working.

A Rinnai Recirculation water heater has self-diagnostic tools that help to keep it working efficiently. Here are some reasons why your Rinnai recirculation may stop functioning:

  • Faulty ignition
  • Buildup of minerals
  • Air supply/exhaust blockage
  • Flame failure
  • Cold water sandwich

In this post, we'll cover solutions to these issues. You'll be able to get to the heart of each problem and troubleshoot your water heater. Continue reading the sections below to know why your Rinnai system isn't working and what you can do to fix it.

Reasons Your Rinnai Recirculation Isn't Working And Possible Fixes

Close up of Gas water heater in the kitchen, My Rinnai Recirculation Is Not Working - Why? What To Do?

As we mentioned above, Rinnai water heaters have a self-diagnostic system that can detect internal problems to let you know what’s going on. In the sections below, we'll cover the five most common tankless water heater problems and how to solve them.

Faulty Ignition

A faulty ignition is a common problem among water heaters. If you're having an ignition problem, you should be able to see Error Code 11.

Code 11 has to do with gas and gas lines. Most of the time, you'd call a plumber for this issue, but if you're familiar with the parts of a water heater, you can check it out yourself.

Here are some things you can do to troubleshoot:

  1. Check the gas meter to see if the gas is on.
  2. Make sure you're using the right type of gas.
  3. Make sure the system is grounded.
  4. Try disconnecting EZConnect or MSA.
  5. Find out if the igniter is working. It might need replacing.
  6. Check for short circuits.

Buildup Of Minerals

Mineral buildup is a typical occurrence among tankless water heaters. This can happen when minerals such as calcium and magnesium aren't cleaned out of the heating chamber.

This buildup corrodes the walls preventing water from being released. This can cause multiple malfunctions with your water heater.

The system might not be able to recognize this problem. Although you may get Error Code 00 or LC, other codes are affected by this problem. This can also cause ignition problems, as included in Error Code 11.

If you're trying to troubleshoot your Rinnai recirculation, you should always address this issue. You can identify mineral buildup by checking the filter for any blockage. This issue is a tough one to solve.

The solution is more on the prevention side. You can prevent mineral buildup by regularly cleaning and flushing your water heater and replacing the filter. Additionally, mineral buildup can cause lime scale buildup, causing the heat exchanger to work twice as hard to get the desired temperature.

Damage caused by lime scale buildup isn't covered in the warranty. If it is clogged badly, you may need to replace it.

If you find yourself with a beeping Rinnai tank, it could be caused by scale buildup. To learn more about this, read this post, “Rinnai Tankless Water Heater Beeping—What's Wrong?” 

Air Supply/Exhaust Blockage

Instant tankless electric water heater installed on white tile wall

Blockage in the air supply or exhaust could be serious. It's either caused by a ventilation or combustion problem.

All Rinnai models have a user manual so that you can have an exact picture of how things should look. So check your manual if you encounter blockage. Some models require that you remove any surrounding material in range of the water heater.

This is because many things can cause blockage, such as weeds, bird nests, rodents, wasps, and anything that can thrive around the area of the water heater.

You know you have this specific problem if you see Error Code 10. Check the pipe vents for holes or connectivity. Any loose pipe vent will cause air circulation problems.

Ensure that there's nothing blocking the venting system or fan and that the dip switch and condensation collar are set properly.

If you're unable to find any problems with the vents, contact a professional.

Flame Failure

Flame failure is associated with Error Code 12, and this is a pretty minor concern. It can happen if you forget to refill the gas. If there's no gas to power the heater up, it will not function. 

But what can you do to ensure that this isn't just a gas-filling problem? Troubleshoot your water heater by following these simple steps:

  1. Check the PC board, power supply, and flame rod for any loose or missing wiring. 
  2. Clean the flame rod and anything around the area of concern for scale buildup or problems.
  3. Look for short circuits
  4. Remove any obstructions from around the venting system, as this can cause ventilation problems.

Flame failure can also happen if the gas line is too small, there is no proper venting system, or there is a combustion or regulator failure. 

You should consult a professional if you can't identify the problem. 

Cold Water Sandwich

The cold-water sandwich is another common issue among tankless heaters, including Rinnai. 

You've probably experienced it. For example, a family member has just finished showering, and you're next in line. When you start the shower, the water feels slightly warm, then a sudden burst of cold water splashes out, and the water goes back to its normal heat setting.

This is annoying, but it's nothing to worry about. The transition is normal because your system is just trying to get rid of the remaining warm water that the previous person hasn't used.

If this happens from time to time and you want to stop it, you can do so by installing a recirculation loop. This maintains the cycle of warm water by returning the cold water to the heater to heat it up.

Check out this Rinnai water heater on Amazon.

How To Reset Your Rinnai Recirculation Water Heater

Tankless water heater in the bathroom, 3D illustration

Resetting your Rinnai can also solve minor issues. The process differs between the two models. Before trying to reset the heater, make sure to turn off all hot water faucets and switch the on/off button twice. Doing this a couple of times will eventually reset the system.

If you have the 2.0 module, you can do a factory reset by pressing and holding the connect button until the LED turns red or white. Immediately release the button and press it three times.

As for the 1.0 module, you only need to press and hold the connect button until the LED light turns white. Then release the button.

Common Rinnai Error Codes

hand rotate temperature adjuster of water heater

Finding out the meaning of error codes is a simple way to know what's going on with your Rinnai. The error codes can be seen either on the temperature display or the clock display, depending on the model.

Error Code 03

This error code will appear when there's been a power interruption while there's an ongoing bath fill. Because of the interruption, the water will stop flowing even if the power comes back on.

To fix this error, turn off the hot water tap and then press on/off twice.

Error Code 14/16

These two error codes are very similar. They're both due to an overheating issue. Error code 14 indicates that there's a thermal fuse problem, while 16 is the system's over-temperature warning.

The solution is to remove objects surrounding your water heater and look for objects in the combustion chamber/exhaust piping.

Clean the heat exchanger fins or replace them if they're beyond repair.

Error Code 58

Getting this error code suggests that there's a secondary condensing heat exchanger sensor. When this happens, you should check the wiring for any broken or loose connection. 

Do check for scale buildup inside the heat exchanger and flush out the water from the heater.

In Conclusion

Shower and electric water heater in the bathroom

The Rinnai Recirculation tankless water heater is made with quality materials and technology. But that doesn’t mean it can’t be affected by wear and tear. Common reasons your Rinnai may stop working include faulty ignition, the buildup of minerals, or flame failure.

To get to the root of the problem with your Rinnai, check for error codes and do a bit of troubleshooting to determine if you can fix it yourself. Otherwise, contact a professional for help.

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