Why Rinnai Heater Red Flashing Light [Solved] 

The following factors are responsible for your Rinnai Heater red flashing light: 

  • Blocked or defective filter 
  • Clogged balanced flue pipe 
  • Restricted airflow 
rinnai heater red flashing light

However, throughout this article, we will take you through every simple solution to the above troubles. So, read this guide continually till the end. 

Rinnai Heater Red Flashing Light [3 Easy Solutions]

You turn on your Rinnai heater, which runs for 20 minutes, and after that, your heater blinks red light. The major factors responsible for this hitch and their practical solutions are: 

rinnai heater

Note: You can also read how to fix MPI monitor 441 burner status flashing

1. Blocked Or Faulty Filter

Before explaining how the clogged or malfunctioning filter causes red light to blink on your heater, check the filter first. Find out whether the filter is non-functioning or dirty. Then step forward according to that. 

Due to the blocked filter, your Rinnai heater shuts off by itself. Dirt, or debris build up in the filter due to periodic maintenance and lack of proper cleaning.

However, the dirty filter becomes defective over time. The filter malfunction causes overheating of your heater. As a result, the red light starts flashing, and the unit won’t re-ignite. 


Properly check your Rinnai heater filter. In case you find a blockage in the filter, you must clean it. Also, maintain a filter cleaning routine regularly. 

But once the filter becomes faulty, we strongly recommend you to replace it. 

How To Clean Rinnai Heater Filter

To clean dirt off your Rinnai heater filter, complete the following step-by-step procedure: 

clean rinnai heater filter 

Step 1: First off, press the power button of your heater once. Or pull the cord out of your electrical outlet to turn off the unit. Go near the back of your heater. Then unscrew its back panel to find out the blocked filter. 

Step 2: Now, you have to locate the control panel. And you will find the filter at the 4-inch back of your control panel. After seeing it, lightly pull out the filter by holding it tightly with bare hands or using something else. 

Step 3: After pulling out the filter, we suggest you clean it properly. Blow the vacuum cleaner on the clogged filter. And then clean the dirt or debris build-up from the filter inside.

Step 4: After cleaning the filter, put everything back in place. Then tightly screw the control panel. Afterward, turn on your heater. Hopefully, your heater will stop flashing red lights. 

How To Replace Rinnai Gas Heater Filter

If your heater flashes red light even after cleaning the filter, that means the filter has deteriorated. And you must replace it. The easy ways of replacing the filter are: 

Step 1: Find The Existing Filter

Turn off your heater. Then following the already mentioned ways, find the filter inside your heater. Now from the service panel, carefully pull out or remove the filter. 

Step 2: Select The Alternate Filter

To replace the malfunctioning filter, bring the new one. The new one should be the same as the model and size of your old filter. 

Also, ensure the new filter size, type, and thickness are similar to the previous one. 

Step 3: Remove The Old Filter

At the final step, it’s time to remove the defective filter of your Rinnai heater. The arrow of your old filter indicates the air moving direction. 

Accordingly, following all these indications will help you to install the new filter in your heater correctly. 

Step 4: Install The New Filter

Remove the packaging of your new filter. And allow the air to flow perfectly through it. Ensure that the arrow of the new filter is in the same direction as the previous one. 

After installing the filter, close the service panel. Afterward, turn on your heater. And the flashing red light will disappear. 

2. Clogged Balanced Flue Pipe

Your Rinnai heater has a balanced flue pipe. It means your heater draws the outside air in one tube, and through another one, it exhausts the air. However, the red light starts flashing on your heater when the balanced flue pipe becomes blocked. 

Most likely, the blockage in the outside pipe is the main culprit for this hitch. The outer pipe draws the cool outside air. Thus it can be full of cob or spider webs, dirt, debris, and foreign objects. 

And all these hinder the external cool air drawing. Ultimately it causes the red light to blink off your heater. 


Begin by checking the balanced flue pipe of your Rinnai heater. At the rear of the unit, you will find two pipes. One is a plastic pipe, and another is an insulated metal pipe. 

From the flue box of your heater, disconnect the plastic pipe. After that, restart your heater. The unit normally running means there is a blockage in the plastic pipe. Thus we recommend you clean it properly. 

3. Restricted Air Flow

Restricted airflow is another culprit responsible for the red light flashing on your heater. Due to insufficient airflow, your heater fails to ignite. 

However, the exhaust and air intake pipe blockage are responsible for inadequate airflow.


To fix the above trouble, you must check the air intake and exhaust pipe. If any pipe is dirty, clean it and improve the airflow. 

Contact Rinnai Customer Support Center

Still, your heater flashes a red light after cleaning the filter and flue pipe properly. If so, it’s better to contact the Rinnai Customer Care Center to fix this hitch. 


Why does my Rinnai gas heater keep turning off?

Your Rinnai heater keeps shutting off mainly due to the faulty pilot light, low gas supply, damaged thermocouple, inappropriate gas pressure, etc. 

What does the economy button do on a Rinnai heater?

The economy button of your Rinnai heater enables the Economy mode. And this mode lessens the selected room temperature by 1°C after 30 minutes of reaching the room temperature. 

How do you turn off the function lock on a Rinnai heater?

For 2 seconds, simultaneously press both the “”and “”buttons. And your Rinnai heater’s function lock indicator will be turned off. 

Why is my Rinnai water heater not working?

Your Rinnai water heater is not working because of the low water flow, blocked combustion chamber, etc. Some other reasons are dirty exhaust piping, clogged heat exchanger, and short cycling. 

Wrap Up

Undoubtedly the red flashing light on your Rinnai heater can bring untold suffering for you. But now you know the major causes of your Rinnai heater red flashing light. 

So, if you experience the same problem, fix the trouble by following our troubleshooting tips. 

However, don’t hesitate to comment and let us know the result of your fixing attempt. We are always here to help you. 

About David

David is a man who loves doing research and finding out the best solution to any type of heating appliance issues like heaters and fireplaces. Whenever he finds the perfect solutions to any issues of heating appliances after doing in-depth research, he loves to share them with his readers. In fact, his aim is to help his readers to fix the issues with their heating appliances easily.More about us .

2 thoughts on “Why Rinnai Heater Red Flashing Light [Solved] ”

  1. Question title Rinnai RC-329ac not coming ON although the power button is OK
    Description : The Heater is going on by pressing the Good Night Button instead of power button If you want to put off the heater it can be off by main power button but now if you want to turn on the heater it will not turn on by main power button. It will only be turn on by pressing good night button rest all operation OK.


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