Richmond Tankless Water Heater Code 12 [Solved]

Richmond Tankless Water Heater Code 12 [Solved]

Richmond Tankless Water Heater Code 12 means flame failure as the unit fails to maintain a flame. It occurs due to gas supply issues, but is not limited to: 

  • Gas valve is off or it’s partially open 
  • Gas service gets interrupted
  • Improper gas pressure
  • Carbon buildup on the flame rod
  • Defective igniter

Throughout this article, I will walk you through every troubleshooting step to erase the error code 12 from the display. 

So, let’s dive in. 

Shall we?

Table of Contents

Richmond Tankless Water Heater Code 12 [5 Reasons & Solutions]

Here are all the troubleshooting steps you should follow to reset the error code 12. 

1. Gas Valve Is Off or Not Fully Open

If the gas valve of your water heater is off or partially opened, no gas will flow to the burner. As a result, you will see no flame when you operate the unit, which triggers the heater to pop up the error code 12. 

How To Fix: 

Check the gas valve and ensure it’s in the On position. When the red gas valve is in line with the pipe, understand the gas flows to the burner. Otherwise, turn the red valve counterclockwise to let the gas flow to the unit. 

2. Gas Service Gets Interrupted

A tankless gas water requires a continuous flow of gas to ignite. If the gas service gets interrupted, no flame will be in the burner chamber. 

How To Fix: 

It’s not a problem at all. All you have to do is- call your gas utility company to get continuous gas service to your home. 

3. Improper Gas Pressure

Proper inlet gas pressure is a must if you want to operate your Richmond Tankless Water Heater efficiently. And the allowable inlet gas pressure range is 4. OO” w.c.-10.5″ w.c for natural gas. 

If you use LP gas to power on your water heater, the acceptable inlet pressure range should be between 8.00″ w.c. and 13.0″ w.c. 

If the inlet gas pressure goes out of range, the burner won’t light and showcase the error code 12 on the display. 

How To Fix: 

For the purpose of input adjustment, you will see a rating plate on the side of the burner. If the inlet gas pressure is high or low, call the gas service company for correction. 

Or, if you are handy enough and have the equipment, watch this tutorial to check gas pressure correctly.

4. Carbon Buildup On The Flame Rod

To operate the heater at its maximum level, the flame rod or sensor (what you call it) should be free from any carbon buildup. If it gets dirty, you will see no flame in the burner. And error code 11 is the result of the flame sensor being covered with carbon buildup.  

How To Fix: 

Clean the flame rod, which will help you erase the fault code 12 flashing on the controller display. The following tutorial will show up the exact way to clean the flame sensor like a pro: 

5. Defective Igniter

A defective igniter is another culprit responsible for the inconsistent flame. 

How To Fix: 

Replacing the igniter is a simple solution to fix this problem. Fortunately, I already published an article on Rheem Tankless Water Heater Code 11, where I described how to replace the igniter. 

Or, you can check the following tutorial to make that replacement: 


Flame loss or failure is what represents the error code 11 on the Richmond Tankless Water Heater. To reset this fault code, ensure: 

  • The gas valve is in the On position to let the gas flow to the unit
  • Call the gas utility company for continuous gas service in your home
  • Adjust the inlet gas pressure if it goes out of the specifications
  • Clean the flame sensor or rod
  • Replace the igniter 

If the error code persists, don’t hesitate to call a certified plumber. 

Check these sources for the accuracy of the information I present: 

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