Rheem Error Codes – How to Read and What to Do

Rheem is a trusted American appliance brand that is close to 100 years old. Rheem offers several water heating solutions, and this article will focus on its line of tankless water heaters. More specifically, it will focus on troubleshooting your Rheem tankless water heater and what to do when you encounter the dreaded error code.

Raheem water heater

How Do You Read a Rheem Error Code?

Error codes are never a pleasant site, but they’re designed to make your life easier. By displaying a code on your tankless heater, you, or a professional, can read the error code to understand what went wrong and how to fix it.

A Rheem tankless water heater has over 30 potential error codes, and the solution will differ depending on the specific make and model of water heater that you have. The most common error codes include Error Codes 5, 11, 13, and 29. Below, we’ll explain how to read error codes on your gas heater and what you should do to rectify the situation.

How to Reset Rheem Tankless Water Heaters

After you see an error code on a tankless water heater, a common first step is to reset the device. Often, resetting the gas water heater allows the device to calibrate itself properly, and then the problem will fix itself.

Before you try anything else, reset your Rheem water heater. Here’s how to do it:

  • Turn off the hot water tap
  • Turn off the device itself
  • Wait for about 20 minutes
  • Turn the device back on

This should allow the device to fully reset itself, and you might find the error code has “magically” disappeared. If not, continue reading.

Related: Resetting a Rheem Tankless Water Heater: Ultimate Guide

How Do You Troubleshoot a Rheem Electric Water Heater – Rheem Error Codes

If you encounter an error code, it will be displayed on your Rheem’s digital thermostat display. You will see a number that is flashing on the display, which will be accompanied by a beeping sound. This number indicates the error you are dealing with. You can find a full list of error codes here.

Consult the guide and see whether you have a grasp on the problem indicated by the error code.

Common Rheem Error Codes

There are over 30 error codes possible on Rheem devices. That being said, customers have reported a much higher frequency of certain error codes, which we’ll cover here. Do note that solving each error code will require a comprehensive understanding of the technical details of a tankless water heater. So, if you don’t think you are up to the task, consult a professional.

Related: Tankless Water Heater Problems? Here’s what to do.

That being said, here are the most common codes and some potential fixes for each:

Error Code 05

Error Code 05 indicates an “Imperfect Combustion Alarm.” If you encounter this, here’s what you can do:

  • See if there is anything blocking the air vent on the device. Also, check that the vent terminal was installed properly on the device. Remove any blockage you see.
  • Check the air inlet filer and clean as required.
  • Make sure that the fan motor is operating properly.

Error Code 11

Error Code 11 indicates an “ignition failure.” Unfortunately, many things can cause an ignition failure. Here’s what you can do:

  • Check that the gas supply is working properly and that the gas pressure is ideal, as per the manufacturer’s recommendations.
  • Check the igniter itself to ensure it is working, including how it was wired to the device.
  • NOTE: Because these are potentially hazardous areas, don’t attempt to fix a Code 11 unless you are a professional.

Error Code 13

Error Code 13 indicates “Flame rod: poor or improper combustion.” Here’s what you should do:

  • Check the air intake and exhaust venting. See whether it’s correctly installed and whether it’s functioning properly.
  • Check the flame rod itself to see whether there are defects.
  • Check the venting on the device for any blockage and clear as necessary.

Related: Rheem Error 13 – Ultimate Troubleshooting Guide

Error Code 29

Error Code 29 indicates that the “temperature is too low on the heat exchanger.” If you encounter this, here’s what you can do:

  • See if the air inlet screen is dirty and clean as necessary.
  • See if the fins on the heat exchanger are dirty and clean as necessary.

These are the most common error codes, as well as the most common fixes for said codes. However, these quick fixes will not always fix your problem. A tankless water heater is a complicated device. Often, understanding how to rectify each error code requires an understanding of how the device works as a whole and how each part works together.

Related: How to Set Temperature on a Tankless Water Heater

More Error Codes

As mentioned above, there are several more error codes you can potentially encounter with a Rheem tankless water heater. The specific error codes might also differ slightly depending on your specific model of Rheem. For this reason, you are best to check the owner’s manual for your device for an accurate, up-to-date list of error codes.

The most common Rheem error codes are found here on Rheem’s official website (click on the first drop-down FAQ section).

Related Posts:

Rheem “INSTANT” Hot Water Heater: Ultimate Troubleshooting Guide

Rheem Power Vent Water Heater: Ultimate Troubleshooting Guide

Top Advice – Contact a Professional

Reading through Rheem’s error code guide, you’ll notice the description for each error code is quite specific. Each refers to a technical component of the tankless water heater and a specific description of the issue. In other words, you’ll need a very in-depth knowledge of these devices to understand each error code and an even more in-depth knowledge to solve it.

Therefore, our top advice is that you contact a professional plumber when you see an error code. Try resetting the device, and if that doesn’t fix the issue, it’s best to have a professional address the situation. Unless you have an in-depth knowledge of water heaters, you’re best to not risk making the situation worse.

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