Rinnai Tankless Error Code 12 [Troubleshooting Updated]

Bathroom, Beginner Info, Tankless Water Heater

Rinnai Tankless Water Heater Code 12 Error
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So, what’s Rinnai Tankless Water Heater Code 12 Error?

Well, in this post, we would be discussing the nuts and bolts of the code 12 error in order to help you clear your doubts related to the topic.

It goes without saying that the brand Rinnai doesn’t need any introduction when it comes to buying a “value for money” tankless water heater.

Not only are they high-quality but also include advanced features that enhance the convenience and usability quotient multifold.

To be honest, Rinnai tankless water heaters are quite popular among our clientele, and trust me for numerous reasons.

However, the most important is its ability to allow you to set the temperature of the outgoing hot water.

Also, they are equipped with advanced and innovative technologies including the one that checks the operation on a regular basis.

If any problem occurs then the error code will be displayed at the temperature display on models MC-91, MCC-91, and MC-502.

On the other hand, you can find the error codes on models MC-100 and BC-100 on the clock display.

Cutting long story short, let’s have a quick look at the various aspects of error code 12.

How do I fix my Rinnai Code 12?

Well, if your Rinnai tankless heater is displaying error code 12 then it simply means your heater is having an issue with flame.

In fact, Rinnai tankless water heater error 12 is associated with flame failure.

If error code 12 appears on the display screen of your Rinnai heater then you might experience a complete loss of flame in your heater.

So, what’s the solution?

Let’s find out…

Since your tankless water heater was working so we’re assuming that it was successfully installed by a technician.

So, the first thing that you need to do is to closely check the loose wiring for the PC board, power supply, and flame rod.

Once you find the wiring intact and well in place without any loopholes, then you need to check for the scale built on the flame rod and clean it thoroughly if it persists.

In the next step, you need to clean the burner of debris and specks of dirt.

At the same time, don’t forget to check for short circuits on the gas solenoid valve.

It’s a good practice to reconnect all the wiring connections.

Also, make sure that the venting system doesn’t have any obstruction.

You need to ensure that the gas combustion chamber of your tankless water heater gets enough fresh air.

Also, make sure the unit vents the gases out correctly.

By doing so, the probability is very high that your problem would be resolved.

Nonetheless, if the problem still persists then you don’t have an option but to contact a certified technician.

I’m attaching a self-explanatory video related to error code 12 troubleshooting for your perusal.

Rinnai Error Code 12 Troubleshooting

It goes without saying that Rinnai Error Code 12 is a flame error code but at the same time, you need to understand that the flame rod isn’t the only culprit, there is more to it.

Let’s have a quick look at some other reasons for flame failure.

No Gas Supply

The error code 12 may display if there isn’t any gas supply.

So, you need to check that all gas valves on the water heater and gas pipes are open.

Moreover, if your tankless water heater uses propane as fuel, then make sure the gas tank is filled with an adequate amount of propane.

In simple words, your gas tankless water heater should get enough amount of gas.

All you need to do is to use the specification found on your tankless unit to see proper inlet pressure.

Also, check if your unit meets the minimum requirements.

At times, improper sizing may lead to a higher pressure drop than the specification.

An undersized tankless unit consists of a smaller diameter and insufficient regulator.

Improper Gas Type

Improper gas type can also create havoc. If you’re using a gas tankless water heater then make sure to use the correct fuel.

A gas tankless water heater is mainly of two types, that is, propane tankless water heater, and natural gas tankless water heater.

Gas Interruption

In order for a gas tankless unit to perform properly it needs an uninterrupted supply of gas.

Make sure your tankless unit gets an uninterrupted supply of gas.

However, if the gas line has air in it, it needs to be purged.

Disconnected or Broken Flame Rod

  • First and foremost, you need to check the status of the flame rod and that it is properly connected
  • If the ceramic sleeve has cracks or is damaged then replace it
  • Moreover, the flame rod and the spark electrode need to be firmly attached to the mounting bracket and shouldn’t be loose or misplaced
  • Make sure wires are properly intact and are without any visible sign of damage or breakage as well as are firmly attached to the rod and electronic board
  • Also, the flame rod must be in contact with the flame to function correctly.
  • You also need to check if the electrode gap is per the specs
  • If your tankless unit is working properly then the flame should have a clear, blue color with a stable pattern
  • However, if the flame rod or spark electrode has deposits (carbon buildup) then you need to use fine grit paper and cloth for cleaning

Exhaust Gas Recirculation

Many first-time buyers aren’t aware of the fact that an error code 12 might appear if the venting system has components not approved by the manufacturer, loose connections, or does not meet recommendations for the venting size, material, and clearances.

If you’re seeing yellow and red-ish burner flame followed by an unstable pattern then it means your unit is having improper gas combustion.

Improper gas combustion can happen when exhaust gas starts coming back instead of going out.

Dirty Components

Ensure that the combustion chamber, fan blower, intake exhaust, and venting system are clean from specks of dirt, and debris so that gas can burn clean and exhaust gases removed safely outdoors.

Rinnai tankless heaters are equipped with several advanced and delicate components sensitive to condensation, contaminants, and buildup.

Issues With Electric Wires

Proper grounding is required as well as all the cables need to be connected tight, dry, and with no damage.

Change the components for the electric short.

Major Component Damages

  • You need to check for major components of health and replace them
    • The electronic board and a gas valve should be replaced at the earliest if found defective
  • Make sure to turn off the gas, water, and electric supply before servicing a unit

What is error 12 on a tankless water heater?

Well, an error code 12 on almost all the tankless water heaters including propane and natural gas reflects flame failure.

Error Code 12 is related to flame failure and if such a problem persists then your heater wouldn’t be able to maintain a flame.

By expediting the aforementioned steps, you would be able to get rid of Error Code 12.

What are the Rinnai Tankless Water Heater Models that Display Error Code 12?

Please find the below Rinnai tankless models that display error code 12.

  • Rinnai Infinity 26 Touch
  • Rinnai Infinity 26
  • Rinnai Infinity 20
  • Rinnai Infinity 16
  • Rinnai Infinity 12
  • B26
  • B20
  • B16

Wrapping Up

First and foremost, I would like to thank you for being with us till the end.

Secondly, I would like to bring to your notice that I along with my core team have put in loads and loads of effort, and in case, you liked our effort then please do share this piece of information with like-minded people and the ones who are in need of it.

After all, sharing is caring, isn’t it?

Cutting long-story-short, Error Code 12 is related to flame loss, and in order to fix it you’ll have to expedite all the steps mentioned above.

Feel free to reach out to us in case of any doubt or query and our team would be more than happy to assist you.

That’s all, as of now :):)

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