Rinnai Error Code 14: All You Need To Know

Beginner Info, Tankless Water Heater

Rinnai Error Code 14 Troubleshooting
As an Amazon Associate, I may earn from qualifying purchases at no extra cost to you. All the products recommendation links on izzysmarthomeguide.com will navigate to Amazon

In this post, I’ll be walking you through various aspects of Rinnai Error Code 14 to help you in the best possible way I could.

Not only will I be explaining in detail the reason for this code but also a user-friendly way to resolve it quickly in a concise span of time.

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

Quite a few of our clients have asked about the reason for the display of code 14 on their Rinnai KB Series condensing tankless water heaters.

If you’re using a Rinnai continuous flow water heater then you would be well aware of the fact that it comes with error code features.

In case of a fault, an error will be displayed either on the system or the temperature controller.

It goes without saying that some error codes have troubleshooting steps that you can consider for fixing the problem.

However, some error codes are serious and need immediate attention.

In fact, you must contact a technician for such error codes.

Before moving further, let’s have a quick look at the Rinnai water heaters that display error code 14.

  • Rinnai Infinity 26 Touch
  • Rinnai Infinity 26
  • Rinnai Infinity 20
  • Rinnai Infinity 16
  • Rinnai Infinity 12
  • B26
  • B20
  • B16
[Related] Should I buy condensing or non-condensing tankless water heaters?

In general, code 14 is displayed on the controller if PCB fails to see continuity through the thermal fuse circuit during the start sequence.


Rinnai Error Code 14 Troubleshooting

If your Rinnai water heater is displaying error code 14 then it simply means that the thermal fuse has been activated so you need to check for restrictions in airflow around the unit and vent terminal.

In simple words, all you need to do is to expedite the below-mentioned steps one at a time.

  • First and foremost, you need to ensure SW 5 in DIPSW 2 is in the off position
  • Secondly, check for low water flow in a circulating system causing short-cycling
  • Once you’re done with the steps mentioned above, the next thing that needs to be done is to ensure dip switches are set to the proper position
  • Moving further, check for foreign materials in the combustion chamber and exhaust piping
  • Also, check the heat exchanger for cracks and separations
    • Check the heat exchanger surface for hot spots which indicate blockage due to scale build-up. refer to the instructions in the manual for flushing the heat exchanger
    • Make sure hard water is treated in order to prevent scale build-up or damage to the heat exchanger
  • Moreover, measure the resistance of the safety circuit
  • Ensure high-fire and low-fire manifold pressure is correct
  • Don’t forget to check for improper conversion of product


  • Ensure dip switch 5 in SW2 is in the off position (SW2 is the lower or second set of white dip switches on the PC board)
  • Disconnect the thermal fuse wiring harness connector that contains the single white wire
  • Connector B8 in the wiring diagram
  • Place a jumper wire* from the PCB side of the B8 connector (disconnected in step 2) to the white wire of the second thermal fuse connector containing white and red wires
  • Connector B7 on the wiring diagram
  • Do not disconnect the B7 connector
  • Attempt to operate the water heater
  • If the unit operates to replace the thermal fuse
  • If code 14 is posted again go to step 5
  • If code 14 is posted after step 4, gain access to the PCB wiring
  • Do not disconnect any connectors from the PCB
  • Place a jumper wire* on the PCB from connector G, Pin 8 (white wire) to connector B, Pin 1 (white
  • Attempt to operate the unit
  • If the unit operates replace the sensor wiring harness
  • If code 14 is posted again, replace the PCB
Rinnai Error Code 14

Reference: media.rinnai.us


In this section, I’ll be responding to the queries related to Rinnai Error Code 14 in order to help our readers in the best possible way that I could.

In case, I’ve not covered your queries then please feel free to reach out to us via the contact form of izzysmarthomeguide.com, and trust me, our core team will respond in less than 24 hours to your queries.

Does it make sense?

How do I fix error code 14 on Rinnai?

In layman’s terms, an error code 14 on Rinnai indicates that your Rinnal water heater is over heating.

The issue could either be the bi-metal safety switch or the thermal fuses.

Don’t worry, the above-mentioned steps will do the trick for you.

How do I reset my Rinnai error code?

  • Turn off all hot water faucets and taps
  • Press On/Off button twice
  • Turn the hot water back on and test

If needed, repeat the above-mentioned steps to reset the system.

It’s A Wrap

Rinnai Error code 14 can be easily troubleshooted by following the steps mentioned in this post.

Probability is very high that you’ll get rid of this error by expediting the aforementioned steps.

However, if that isn’t the case, then please contact a techinican for the way forward.

Thanks for being with us till the end.

Do let us know your view on this post in the comment section.