Pentair Heater Error Codes [12 Easy Solutions]

If you see error codes on your Pentair heater, you should take appropriate actions as soon as possible. The 12 Pentair heater error codes indicate crucial Pentair heater issues. If you know what these error codes mean and the appropriate solution to these codes, you shouldn’t face any problems with your water heater.

And in this article, we will talk about just these. Here you will get to know the 12 Pentair heater error codes that are: E05, E06, R13, R14, AD0, ERR PS, ERR HLS, ERR AFS, ERR IGN, ERR AGS, ERR SFS and E01/126. By the end, you will be able to deal with all these codes easily. Our methods will help you solve Pentair Mastertemp 400, Pentair Mastertemp 250, Pentair Mastertemp 125 error codes and other Mastertemp error codes as well.

So stay tuned.

12 Pentair Heater Error Codes, Their Meanings & Solutions

To properly solve Pentair error codes, you have to know the code’s meaning along with the solutions. This is why below we have elaborated on the 12 Pentair heater error codes, their causes, and effective solutions. Take a look. 

1. Pentair Heater Error Code E05: Stack Flue Sensor Is Open

The E05 error code appears when the stack flue sensor detects that the exhaust temperature has exceeded 176°C. As a result of this issue, your heater can shut off completely.


To deal with Pentair heater error code E05, You have to ensure certain things. Here they are:

  • Turn off the Pentair heater
  • See if the thermal regulator has gone bad and causing the water to stay in the exchanger
  • Empty the accumulated water from the heat exchanger
  • See if the gas pressure is fine
  • Make sure that the orifice is not blocked

After ensuring all these points, your Pentair heater won’t have the E05 error code on any longer.

2. Pentair Heater Error Code E06: Stack Flue Sensor Is Shorted

The most common reason why flue sensors are shorted is improper gas flow in the system. It can happen as a result of many issues, such as a broken gas valve.


In order to fix error code E06 you need to:

  • Check the gas pressure flowing in the system
  • Make sure that the gas pressure is within the perfect limit
  • See if water is clogged anywhere inside the system (it can cause overheating)
  • Make sure to use the right fuel 

And this is how you can get rid of Pentair heater error code E06.

3. Pentair Heater Error Code R13: Startup Mode

Pentair heater code R13 is not actually an error code per se. Rather it is actually an indication of heater startup. When you turn on the device, this code will come up in your Pentair heater display, but it will go away once the device is completely booted up. In other words, you won’t have to do anything when this error code comes up. 

4. Pentair Heater Error Code R14: Revision Mode

Pentair heater code R14 means that the heater is currently in revision mode. The revision mode is a checkup of your device. When your heating system goes through every setting, the error code R14 appears. This is why it usually comes up right before another error code or error message. 

5. Pentair Heater Error Code AD0: Bad Keypad

Generally, AD0 is related to the stack flue sensor. But the stack flue sensor is set with one key on the keypad. This is why it can be concluded that the error code AD0 means that there is something wrong with the keypad.


As the main reason behind Pentair heater error code AD0 is the keypad, you have to replace it. You can do it easily following these steps,

  • Open up the front panel of your pentair heater
  • Detach the membrane and wires connected to the heater control pad
  • Remove the heater control pad from its place
  • Take a new Pentair heater control pad
  • Rewire the new control pad in the same manner as the last one
  • Put everything back on after ensuring proper wiring

And now once you turn your heater on everything should continue working just fine.

6. Pentair Heater Error Code ERR PS: Water Pressure Switch Is Open

The error code ERR PS means that the water pressure switch is open, and there is a chance of overflowing.


In the case of Pentair heater error code ERR PS, you have to ensure that there is no unwanted water flow. You can do this easily by rotating the water pressure switch. However, if the water is still flowing through the heater, you have to stop it by fixing the water flow pipe. You may need to call a professional for help.

7. Pentair Heater Error Code ERR HLS: Hi Temperature Switch Is Open

This problem occurs when the temperature falls below 57°C. It can happen due to extreme weather, faulty water flow, etc. 


This situation is actually a bit tricky. To solve it properly, you have to make sure the water that passes through the heat exchanger is more than 57°C. This way, the temperature switch will get the reading it was looking for. And as a result, the error code will be gone as well.

8. Pentair Heater Error Code ERR AFS: Airflow Switch Is Open

In a good Pentair heater, perfect airflow is established in the system within a minute of a startup. If the airflow is not adequate within this time, the heater turns off automatically. The error code ERR AFS is shown as a result of this issue.


You have to make sure that the blower is not restricting airflow to solve this error code. In order to do that, you have to:

  • Turn off the heater
  • Open up the blower fan cover
  • Look for any obstructions or dirt clogged there
  • Clear out the fan thoroughly 
  • Make sure that the fan is strongly secured in its place
  • Put everything back in their place

Now once you put the power back on, your Pentair heater shouldn’t show the error code ERR AFS.

9. Pentair Heater Error Code ERR IGN: Ignition Control Module

The error code ERR IGN comes up in the Pentair heater when the ignition control module fails to ignite the heater. So basically, in this error code, you won’t get any ignition in your heater.


The solution to this problem is actually very simple and easy. You only have to make sure that the burner is okay. Here’s how:

  • Press the OFF button
  • Open up the heater to reach the burner inside
  • See if anything’s stuck on the burner
  • See if the burner connection is secured with gas and other lines
  • If the burner is damaged, unscrew it from its place and install a new one
  • Put everything back

At this point, there shouldn’t be the error code ERR IGN displayed on your Pentair heater.

10. Pentair Heater Error Code ERR AGS: Gas Shutting Off Automatically

The gas flow in your Pentair heater can shut off on its own due to a low flow rate or faulty pressure switch. When this happens, you get the error code ERR AGS on your heater display.


There are a few things you can do in the case of Pentair heater error code ERR AGS. Here they are,

  • See if the water flow rate is above the minimum
  • Adjust the water flow rate
  • Make sure that the water temperature is below 60℃
  • Replace the high limit switch 

If this doesn’t solve the issue, you have to take your heater for servicing to the professionals. 

11. Pentair Heater Error Code ERR SFS: High Stack Flue Temperature

The ERR SFS error code occurs when the temperature of the stack flue gets more than 248°C. Such a situation usually occurs due to a faulty thermal regulator or incorrect fuel supply.


In this case, you have to deal with certain points. Here they are:

  • Open up the Pentair heater
  • Locate the thermal regulator there
  • See if it’s perfectly placed in its position
  • Handle the heat exchanger coils clogs, soot, or leakage
  • Make sure that the gas pressure is fine

After all these, your Pentair heater shouldn’t show the error code ERR SFS again.

12. Pentair Heater Error Code E01/126: Water Temperature Sensor Is Open

Pentair heater error code E01 and Pentair heater error code 126 is basically the same things. Both these error codes deal with the faulty water temperature sensors of the heater.


You can adapt the following methods to deal with Pentair error codes E01 and 126. 

  • Turn off the device
  • Open the back panel of the device
  • Locate the thermostat wiring
  • If the wiring seems problematic, replace it
  • If the wiring is okay, then replace the thermostat

And this is how you can perfectly fix the error code E01 and the error code 126.

Now that you know everything about the 12 Pentair heater error codes, there shouldn’t be any issue bothering you longer.


What does the service system light mean on the Pentair pool heater?

The service system light on your Pentair pool heater means that the water flow to the heater is not enough. 

What does the stack flue sensor do?

The stack flue sensor in the Pentair heater keeps the flue gas output within 500°F.

How do I reset my pool heater?

To reset a pool heater, you have to press and hold the Up & Down buttons on the control panel.

What causes a stack flue sensor to go bad?

The stack flue sensor can go bad due to sooted exchange, low water flows, and a scaled-up exchanger. 

How do you test a stack flue sensor?

Use a multimeter to test the stack flue sensor. Any reading above 3.5 ohms means that the sensor is okay.

Final Verdict

Dealing with all the Pentair heater error codes is easy. You just have to know the proper solution. And in this article, we have shown you just that. Overall, you won’t have any problem with your Pentair heater from now on.

However, you have any questions, let us know in the comment below.

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4 thoughts on “Pentair Heater Error Codes [12 Easy Solutions]”

  1. r14 revision mode. Won’t leave this mode and is showing no further error codes. The unit try’s twice to turn on then shuts down.

    • Hi Daniel

      Pentair heater code R14 means that the heater is currently in revision mode. The revision mode is a checkup of your device. When your heating system goes through every setting, the error code R14 appears. This is why it usually comes up right before another error code or error message.

      Wait and see, which error code shows and deal with it.

      Well, your unit may shut off due to lack of sufficient water flow to the unit or gas flow restriction for a dirty burner assembly, faulty vales setting if you have any, problematic bypass valve in the unit, and faulty thermal regulator. Check and make sure which one is the main reason behind your issue then fix it. If you are not comfortable with the whole procedure, take help from a tech.


  2. New pad and mother board installers and when I turn it on the heater does not work but it reads out on membrane is “3 wire controll”. Any idea what is going on?


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