In this guide, we will take a look at how to troubleshoot Rinnai Tankless Water Heater Code 11 error. In this article, we will cover 7 reasons at a glance that could cause Rinnai fault code 11 to appear on the unit.

• The Rinnai Tankless Water Heater could possibly be experiencing a glitch with the gas supply.
• The type of gas or pressure of the inlet gas is incorrect for Rinnai Tankless Water Heater.
• The gas lines of Rinnai tankless water heaters contain air.
• The wires leading to Rinnai Tankless Water Heater’s PC board are damaged.
• There is a loose wire on the flame rod.
• Flame rods that are loose or floating.
• Igniters that are dirty or defective should be replaced.

I will walk you through every problem-solving step to fix these seven factors to clear the Rinnai code 11 error message. 

So let’s get started with a guide on how to troubleshoot Rinnai Code 11 error reasons and how to fix them. 

As it relates to Rinnai Tankless Water Heaters, what does Error Code 11 indicate?

Rinnai error code 11 indicates that there is a problem with the ignition system (there is no spark). Your Rinnai tankless water heater usually has a faulty igniter, an insufficient gas supply, or a dirty flame rod. 

Rinnai error code 11 can also be caused by air in the gas line, loose or damaged flame rod wires, and blocked condensate lines. 

Those issues I mentioned must be fixed in order to erase the Rinnai error code 11 message. As we proceed through the next chapter, we will guide you through every step of troubleshooting this water heater issue. 

Here are seven easy solutions to fix Rinnai Tankless Water Heater Code Error 11.

As a result of this chapter, we will be introducing you to all the possible culprits responsible for the Rinnai error code 11. However, I will walk you through every step of the troubleshooting process.

1. Rinnai Code 11 indicates that the gas supply may be turned off.

Without fuel, your gas tankless water heater cannot be ignited. If you do not turn on the gas at the unit, meter, or cylinder, your water heater won’t get fuel for combustion. Rinnai error code 11 will appear if you attempt to ignite the unit without turning on the gas supply. 

What is the best way to fix a gas supply that may have been turned off issue?

Ensure that the gas supply to the unit is allowed by turning the gas control valve counterclockwise. As an alternative, if you have a propane tank, be sure to turn on the valve when the tank is full. 

2. Rinnai Code 11 due to the incorrect type of gas or the wrong inlet pressure of the gas.

Gas or propane can be used to operate Rinnai Tankless Water Heaters. If you use the wrong type of gas, you will never be able to ignite the unit. The gas pressure at the inlet should also be within the limits, otherwise Rinnai error code 11 will occur. 

What are the steps to fix an incorrect gas type or incorrect inlet gas pressure?

Make sure you use the right fuel by checking the manual. Water heaters that require natural gas for operation should be powered by gas. The propane line should be connected to your water heater if it is not already connected. 

Make sure that the inlet gas pressure at the unit is correct as a next step before proceeding. Gas pressure should range from 3.5 inches WC to 10.5 inches WC on Rinnai gas tankless water heaters. Propane units, however, should have an inlet gas pressure between 8 and 13.5 pounds per square inch. 

If the gas supply pressure is out of range, it is highly recommended that you call a qualified technician. 

3. There is air in the gas lines in the Rinnai, which results in Code 11.

All gas lines should be purged before turning on your tankless water heater. In the event that there is dirt or air in the gas lines, your water heater may malfunction. However, water flow can also be affected by air in the water lines, preventing the unit from lighting. Guess what, error message 11 will pop up on the display. 

Is it possible to fix the air in the gas lines of a Rinnai tankless water heater?

Due to the high gas flow, a tankless water heater will usually purge the line in seconds. As a first step, you should open the water heater’s service valve and leave it until you can smell gas clearly coming from your water heater. Moreover, close the service valve and wait a few minutes before connecting the gas line to the water heater. 

The unit must also be bled of air from the water lines in order to function correctly. Run the hot water faucet slowly and for a few minutes to allow air to flow through the pipe. In addition, if you still see air bubbles coming from the hot water faucets, keep them open until they stop. 

4. The wires leading to the PC board on the Rinnai tankless water heater are damaged.

Error code 11 can be thrown if the wiring leading to the PC board becomes loose or damaged. Rinnai tankless water heaters come with five different electric connectors. However, it is important to inspect each connector to ensure that the wires are intact and that there is no visible damage to them. 

What is the best way to fix the Rinnai tankless water heater’s PC board?

It is recommended that the wiring leading to the PC board be inspected by a certified electrician. If required, you may need to replace the wiring or the PC board if the problem persists. You may take a look at the following tutorial in order to learn how to install a PC board.

5. A Rinnai tankless water heater has a loose flame rod wire.

There is a loose connection between the flame rod and the ignition wire that causes ignition failure. Damaged or disconnected flame rod wires will prevent your tankless water heater from igniting. The unit pops up code 11 when the flame rod wire is inserted into the wrong flame rod. 

What is the proper approach to fixing a loose flame rod wire?

Again, I recommend you have the flame rod wiring inspected by a professional. It may be necessary to replace the wiring on the flame rod or the flame rod itself if this is the case. 

6. There is a loose flame rod attached in front of the Rinnai tankless water heater.

You should tighten the mounting brackets of your Rinnai tankless water heater if the flame rod is loose or floating. 

What is the best way to fix a loose flame rod on a Rinnai tankless water heater? 

The upper access panel must be removed in order to access the upper portion of the unit. Once that is done, ensure that the flame rod is tightly secured in the mounting bracket. Moreover, you cannot move the gasket with your fingers if it is intact. Reinstall the flame rod with a new gasket if it’s loose and clean it if necessary. 

7. Rinnai tankless water heaters have dirty or defective igniters.

In order to ignite the water heater, an igniter is used. If this component becomes dirty or defective, your water heater will not be able to ignite. As a result of this, Rinnai error code 11 will appear on the display of the controller. 

What can be done to fix a dirty or defective igniter on a Rinnai tankless water heater?

Unscrew four nuts on the access panel and turn off the unit. Once the igniter is located, clean it if there is any buildup. However, this video will help you if cleaning the igniter does not work and you need to replace it.

Final thoughts

A Rinnai tankless water heater displays error code 11 if the gas is not turned on either at the unit, the gas meter, or the tank. The Rinnai code 11 problem can be caused by a defective igniter, a loose flame rod, and air in the gas line. 

Following the instructions below, I explained how to troubleshoot the problem and how to clear the error message from the display.  

If the error code returns after trying all the steps I described, there is likely something critical wrong. Get in touch with a professional if you are experiencing difficulties with your Rinnai tankless water heater. 

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