How To Deal With Pentair Heater Error Code R13 [Solved]

The R13 code on a Pentair heater is not an error code. Rather, it’s a sign that the heater is about to turn on. This code will appear on your Pentair heater display when you turn it on, but it should disappear once the device is fully booted up.

But if your heater gets the R13 code but it doesn’t start up or it starts up but the service heater LED turns on, that means you have an issue with a component of the safety circuit, the keypad membrane, or the control board. 

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What To Do When You Get Pentair Heater Error Code R13?

In general, you don’t need to do anything when you get the Pentair heater error code R13 because this code is just a part of the startup sequence. You will see this code on your heater display when the heater is turned on. 

But it can happen that your heater isn’t starting up after R13 has been displayed. Maybe that is why you thought it was an error code in the first place. Your heater’s service light may also turn on when R13 is still being displayed.

All of these events aren’t normal. Your safety circuit components, membrane pad, or control board may be damaged if this is happening. Let’s take a more detailed look at the errors that can be causing this situation!

1. Pressure Switch Or PS Error

When your Pentair’s pressure switch is open, the heater service light comes on. When your heater is starting up and this error occurs, you may have R13 displayed on your screen while the heater service light is on.


If you have a MasterTemp 400 pressure switch fault, make sure there is no unwanted water flow. Adjusting the water pressure switch is a simple way to do this.

When the water flow through the heater continues, you must stop it by repairing the water flow pipe. It’s possible that you’ll need to hire an expert to inspect your heater.

2. High Limit Switch Or HLS Error

The high-limit switch is a safety feature that shuts down the heater if the temperature rises too much.

Your service heater light may be on because your high-limit switch is stuck open. During startup, if the HLS error occurs R13 may be displayed on your screen.

If the temperature reaches below 57°C, this issue will occur. Extreme weather, faulty water flow, and other reasons can all play a role.


Ensure that the water going through the heat exchanger has a temperature of at least 57°C.

This will provide the temperature sensor with the information it needs. The error light should be turned off. If it’s on, the high limit switch may need to be replaced.

3. Air Flow Switch Or AFS Error

Your service heater light might turn on if the airflow switch is open. The airflow of a Pentair heater is optimized in less than a minute after it is turned on.

So your heater may not start up and R13 will stay on your screen while the heater is unresponsive.


To fix this problem number, make sure the fan isn’t obstructing airflow. You’ll need to complete the following:

  • Turn the heater off.
  • The cover of the blower fan should be removed.
  • Check the area for any obstructions or barriers.
  • Make sure the fan is completely drained.
  • Ascertain that the blower is firmly attached to its location.
  • Reassemble everything and put them back in their proper location.

At this time, the problem with your Pentair service heater light on should be resolved.

4. Automatic Gas Shutoff Or AGS Error

Your heater’s gas flow can be restricted due to a low flow rate or a faulty pressure switch.

The service heater light may turn on as a result of this. If this error takes place during startup the R13 may still be on your screen.


There are a few options for dealing with the Pentair heater AGS problem. These are the following:

  • Examine the flow rate of the water to see if it exceeds the minimum.
  • Adjust the water flow rate. 
  • Make sure the water isn’t over 60 degrees Celsius.
  • It’s time to replace the high-limit switch.

If this does not cure the problem, you will have to hire a professional to service your heater.

5. Stack Flow Switch Or SFS Error

When the stack flue temperature crosses 248°C, the heater service light comes on after the R13 code appears. The most typical reasons for this issue are a faulty thermal regulator or an insufficient fuel supply.


You must address a few issues when this error occurs. Follow the instructions given below to fix an SFS error. 

  • On the Pentair heater, turn it on.
  • A heat regulator should be present.
  • Now check to see that the thermal regulator is in the proper location.
  • Inspect the heat exchanger coils for any obstructions, soot, or leaks.
  • Check to see if the gas pressure is sufficient.

Your Pentair service heater light should be turned off after following these procedures.

6. Defective Keypad Membrane

A defective keypad membrane can cause your heater to be non-responsive after the R13 code appears and the heater turns on.


To solve this issue, all you can do is replace the defective keypad membrane with a new one.

7. Bad Control Board

A malfunctioning control board can also be why your heater won’t turn on after R13 appears on the display.


You need to have your control board replaced. Contact Pentair customer care to get a new control board. You can hire a professional to replace the control board for you.


What does R14 mean on a Pentair pool heater?

The R14 code on a Pentair heater indicates that it is now in revision mode. The revision mode performs a device checkup. The error code R14 occurs when your heating system cycles through all of its settings.

Why does my Pentair pool heater keep shutting off?

Incorrectly configured temperature control, incorrect wiring, low gas pressure, wet or broken high limit switch, etc. are common causes of your Pentair MasterTemp 400 switching off? Read our article on Pentair MasterTemp 400 shutting off to learn more.

Can a pool heater overheat?

Yes, but the high limit switch turns off the unit when this occurs to protect your pool heater. 

Why won’t my pool heater fire up?

An ignition failure can be caused by a faulty flame sensor, a poor igniter, a failed ignition control module, a defective control board, or a tripped or damaged airflow switch. Read our article on Pentair heating light flashing to fix this issue.

What is a heater manifold?

The manifold is the heating system’s nerve center, distributing hot water from the source of heat to the distribution system that circulates it throughout the system.


Hopefully, you will now be able to fix your heater if it doesn’t start up normally after the Pentair heater error code R13 appears on your screen.

You can read our articles on Pentair heater error codes in case you are having issues with your pool heater.

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 .

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