Rinnai Tankless Water Heater Error Code 11 [Quick Fix]

Bathroom, Beginner Info, Tankless Water Heater

Rinnai Tankless Water Heater Code 11
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So, are you struggling with the Rinnai Tankless Water Heater Code 11 Error?

Well, if that is the case, then you’ve landed on the correct post as we would be discussing the nuts and bolts of Rinnai Tankless Water Heater Code 11.

Trust me, whether you’re a first-time buyer or a seasoned professional, the information that we’re gonna share will definitely help you in troubleshooting your Rinnai Tankless Water Heater.

So, without any further ado, let’s begin…

Frankly speaking, I too own a Rinnai tankless hot water heater so I know very well how frustrating it sounds when the code 11 error beeps.

In simple words, once you’ll get this error the ignition will get off making the scenario pathetic as you wouldn’t be getting any hot water, and if you’re in the mid of the shower then only god can help you.

Unfortunately, getting rid of this error code can be tedious and time-consuming because there are numerous reasons for it.

Trust me, our intention isn’t to make you afraid but at the same time, we love to share genuine and unbiased information.

Keep in mind, the potential cause of the Rinnai Tankless Water Heater Code 11 error could be an issue with the ignitor, gas supply, flame rod, venting, excess moisture, and many more…

7 Reasons that May Lead to Rinnai Error Code 11 on your Tankless Unit
  • Gas supply to the unit may turn off or not adequate and at a proper pace
  • Wrong inlet gas pressure or incorrect incorrect gas type
  • Presence of air in the gas line
  • Damage in the wires leading to PCB
  • Loose flame rod wire
  • Loose or floating flame rod
  • Dirty to the defective igniter

A majority of your effort will go into doing root analysis and finding the main cause behind the code 11 error.

Because you can get your tankless water heater running only when you’re able to find the right cause as well as apply the right solution.

Don’t worry, as we would dive deeper into each cause and help you in figuring out the right way of testing and fixing the problem.

Does it make sense?

Case 1 : If problem is with the ignitor

Let’s assume that you’re getting the Rinnai Tankless Water Heater Code 11 due to the malfunctioning of the ignitor.

So, in that case, you need to expedite the below-mentioned steps.

  • First and foremost, you need to cycle the unit and check whether there is a spark from the ignitor or NOT
    • If there is SPARK, it means the ignitor is doing its job perfectly
    • On the other hand, if there is NO SPARK, then it could be because of damaged or loose components
      • Another cause could be the incorrect voltage of the electric board
  • At the same time, you also need to check for build-up on the ignitor
    • In case, you found scale or carbon then all you need to do is to follow the instructions mentioned by the manufacturer for cleaning & removing build-up

Case 2: If problem is with the gas supply

  • We’re assuming that the problem is with your gas supply so in that case, you need to expedite the below-mentioned steps
    • Make sure that the gas supply is ON and also check other gas-powered appliances such as stove, laundry drier, etc
    • You need to ensure that the gas pressure is adequate by cleaning the specks of dirt and debris from the system
    • Most importantly, if you’ve recently installed the Rinnai tankless water heater then you need to purge the air from the gas line

Case 3: If the problem is with the flame rod

  • You might be inquisitive to know what needs to be done in the case, the problem is with the flame rod, right?
    • First and foremost, you need to inspect the flame rod and make sure that the wiring is in good condition
    • Secondly, keep an eye on the connections and ensure that all of them are right positioned and safe
    • Lastly, look for specks of dirt & debris on both the flame rod as well as a gasket, and do the needful if needed
      • At the same time, don’t forget to replace damaged or cracked parts if any

Case 4: What if, the problem is with the venting

  • Make sure that the intake and exhaust vents are FREE from the blockage
  • Also, ensure that the venting components aren’t faulty and installed properly because in the absence of any of the two airflows can be impacted as well as build-ups on the rod may happen

Case 5: Is the Rinnai tankless water heater code 11 error due to water & moisture

  • You need to look for signs of leaks & excessive moisture on your unit as it may be the cause of the corroded parts or impacted electrical connections
  • In the case of condensing units, you need to inspect the condensate drainage
  • Also, make sure that the heat exchanger as well as the space between fins is free from debris, and dust in order to get rid of any irregular combustion

To be honest, from our past experience and the knowledge that we’ve gained over a period of time, all I can say is that if you’ll carefully expedite the aforementioned steps then the probability is very high that you’ll be able to find out the root cause of Rinnai Tankless Water Heater Code 11.

In case, you’re NOT able to figure out the reason behind the code 11 beeping then I would suggest you should contact the Rinnai support team or the technical experts in your vicinity.

Some other issues that may lead to the occurrence of the Rinnai error code 11 display

Wires leading to PCB get damaged

If wires leading to the PCB are either loose or damaged, the unit may display an error code 11.

In such a scenario, you need to look for visual damage as well as check the wires on each connector.

Most Rinnai tankless water heater consists of five different electric connectors.

If you’re getting error code 11 due to the damage of wires leading to the PCB, then the best way to deal with it is to call a certified technician.

If needed, you may have to replace the wiring or the PC board itself.

I’m attaching a self-explanatory video for your perusal.

Incorrect gas type or wrong inlet gas pressure

Rinnai tankless gas water heaters are mainly of two types: natural gas tankless water, and propane tankless water heaters.

It goes without saying, the wrong type of gas supply will never ignite your tankless unit.

At the same time, you need to ensure that the inlet gas pressure is within limits else it may lead to error code 11.

To deal with such scenarios, you need to check the manual as well as ensure the right type of fuel.

For example, if you own a propane tankless water heater then you shouldn’t supply natural gas to the unit.

Another important thing you need to look for is to ensure that the correct inlet gas pressure is at the unit.

On a Rinnai gas tankless water heater, the inlet gas pressure should be between 3.5” WC to 10.5” WC.

On the other hand, for a propane tankless water heater, the inlet gas pressure should be between 8” WC to 13.5” WC. 

You might be wondering what if the gas pressure goes out of control.

To be honest, the best solution would be to contact a certified technician at the earliest.


Let’s have a quick look at some of the frequently asked questions related to Rinnai Tankless Water Heater Code 11.

In case, we’ve not covered your question related to the topic then feel free to reach out to us via the contact form, and our core team would be more than happy to assist you.

What is code 11 on a tankless water heater?

It simply means that your tankless heater isn’t firing up to heat the water.

There could be numerous reasons for the code 11 errors including insufficient gas supply, insufficient airflow, or debris on the ignition plug.

Why is my Rinnai beeping 11?

It is an indication that there is no ignition in or gas supply to your hot water system.

The aforementioned steps will help in doing the root cause analysis and finding the reasons behind your Rinnai beeping 11.

Wrapping Up | Rinnai Tankless Water Heater Code 11 Troubleshooting

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

Secondly, I hope that you’ve got a satisfactory answer to your question, Rinnai Tankless Water Heater Code 11 Troubleshooting.

And, in case, you liked our effort and want to appreciate us, then please do share this post with like-minded people and the ones who are in need of it.

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That’s all, as of now :):):)

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