Pentair Heater E05 Error Code [Reasons + Solutions]

The Pentair heater e05 error code is one of the 12 error codes for this pool heater. Now there are quite a few reasons why this error code appears, including a faulty stack flue sensor, damaged thermal regulator, and improper gas pressure.

pentair heater E05 error code

Low water flow and loose wiring also contribute to the Pentair Mastertemp e05 code. Fixing the error as soon as it appears is important for the performance and longevity of the pool heater. So, continue reading to know how to fix the Pentair E05 heater error.

Pentair Heater E05 Error Code [Reasons + Solutions]

Here, we will explore and discuss each and every reason that results in the E05 Pentair heater error. We will also tell you the solutions that will help you to fix the problem.

Note: You can also read how to fix the Pentair heater error codes problem.

1. Faulty Stack Flue Sensor

The work of the stack flue sensor is to detect the exhaust temperature of the heater and make sure that it does not exceed 176 degrees Celsius.

If the sensor fails to properly detect the temperature or it exceeds the limit, then the E05 error code appears. Not only that, but it also causes the Pentair pool heater to turn off.


Open the control panel and make sure that the stack flue sensor is working properly. Make sure that there are no parts of the sensor that require work. Repair or replace the sensor properly if there are any issues.

2. Damaged Thermal Regulator

In the Pentair pool heater exchanger, the thermal regulator helps the water reach a certain temperature and heat up the pool water. However, a damaged thermal regulator often prevents the water from flowing out, causing it to be trapped in the exchanger.

The accumulated water will not allow the Pentair pool heater to work properly or shut off completely. And it will also cause the display of error code E05.


Examine the thermal regulator to see whether it is offering a proper performance or not. Empty all the water that has accumulated in the exchanger properly. Take out the thermal regulator and replace it with a new one.

3. Improper Gas Pressure

The gas pressure to the Pentair pool heater often gets obstructed due to clogged gas pipes, incorrect pressure settings, and turned off gas valves.

These factors prevent the gas from reaching the heater and performing properly. It also causes the heater to shut down completely and display the E05 code on the Pentair heater.


Check the gas valve and make sure that it is turned on completely. Clean the gas pipes properly if they are clogged and do not forget to turn off the valve before cleaning. Turn the valve back on and set the pressure to the proper temperature.

4. Low Water Flow

A thin or low flow of water to or from the water heater can also cause the e05 on Pentair heater display.

The reason behind this is that the heater does not get enough water to heat up properly causing an imbalance in temperature. The thin flow of water is typically a result of scaled-up pipes or improper water pressure.


Examine the water pipes and make sure that they are clean. Disconnect the main water line and turn off the heater before properly cleaning the pipes.

Connect the water line and turn on the heater to see the flow of water. Adjust the valves on the main line to set the water pressure at the right level.

5. Loose Wiring

The wires connected to the stack flue sensor of the Pentair pool heater often loosen up automatically or get damaged.

This prevents proper connectivity between the system and the sensor, causing the heater to shut down and display the E05 error code.


Open up the control panel and check the wires connected to the stack flue sensor. Take the sensor out and make sure that all the wires are properly connected.

Fix the loose wiring and replace the damaged wires. Clean the sensor along with the terminals and put it back in place. Turn off the heater to see that the E05 error code is fixed.


Can I Fix The Error Codes On My Pentair Heater On My Own?

Yes, you can fix the error codes on the Pentair heater by identifying the issue and its solution. However, we often suggest professional help if the issue is complex.

How Do I Clean My Pentair Pool Heater?

Turn off the main connection and clean all the airflow, water, and gas pipes properly. Make sure that you maintain a cleaning schedule to keep the pipes clear and functional.

How To Maintain A Pentair Pool Heater?

Conduct checks on all the parts and sensors on a regular basis. Fix or replace the faulty parts, wires, or pipes as soon as you notice them.

How Long Does A Pentair Pool Heater Last?

A Pentair pool heater typically functions for 6 to 12 years on average. However, properly maintaining the pool heater and usage will allow the heater to last for a longer period of time.


Fixing the error codes immediately is a must in the Pentair pool heater to avoid further problems to happen. Already you know how to sort out the reasons behind the code and solve your Pentair heater error code E05.

So, whenever the error code pops up on the heater display, fix it with the help of our guide by yourself.

Leave a comment in the box below if you have any questions about the Pentair pool heater. We will get back to you as soon as possible with the best possible answer. 

About William

William is the founder of He has real life practical skills in fixing smoker & heating appliance issues. He loves to share his knowledge & helps others in fixing their appliances & saving their money. William firmly believes that anyone can repair his or her unit with the correct guidance & knowledge. See more at about us.

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