Sta Rite Pool Heater Keeps Shutting Off [7 Easy Solutions]

The main reasons why your Sta Rite pool heater keeps shutting off are a dirty cartridge filter, faulty thermistor, and ignition issues.

Plus, a bad thermal regulator, wiring issues, a malfunctioning blower fan, and a leaking canister also could be the culprit behind your pool heater problem.

sta rite pool heater keeps shutting off

Keep reading this article to find out more about these issues that cause your pool heater to shut off.

You’ll also learn how you can fix each of these issues and get it back to normal operating conditions. Let’s dive in!

Table Of Contents

Sta Rite Pool Heater Keeps Shutting Off [7 Easy Solutions]

We’ll explore the seven major reasons why your pool shuts off in this Sta Rite pool heater troubleshooting guide. Here they are:

Note: You can also read the Sta Rite pool heater troubleshooting guide.

1. Dirty Cartridge Filter

If your Sta Rite pool heater won’t stay on, the first thing you should check is the filter. If the filter gets dirty, it’ll reduce the flow of water in the system and cause the heater to shut off.

sta rite pool filter cartridge

If the Service system light is on, that’s a good indicator that you need to look into your filter.


You have to clean the filter if it has become dirty to get the proper flow of water so that your heater can keep running.

You’ll need a screwdriver and a silicone spray with a high-pressure nozzle to clean the filter. Follow these steps to clean the filter:

  • Turn off the heater before you start working on it. Make sure your pump basket is clean.
  • Locate the drain plugs and open them. Take off the lid of the heater using the screwdriver.
  • You’ll see two filters – the small one on top and the big one on the bottom.
  • Pull out the small filter first using both hands. Spray the inside and outside of the big filter with water.
  • Dirty water will come out of the drain plug if you’re cleaning well.
  • Spray the small filter the same way with water.
  • Put the filter back in the way it was when you took it out.
  • Make sure it’s sitting tight and not wobbling to prevent water from leaking.
  • Use a silicone spray on the O-ring of the heater.
  • Put the lid and the drain plugs back on. Spray the drain plugs with silicone spray.

Now you’ve successfully cleaned your filter. If it solves the problem and your heater stays on, you’ve solved the problem.

Otherwise, it’s time to get back to the drawing board and look for other potential causes.

2. Faulty Thermistor

The next most common reason why your pool heater won’t stay on is because of a faulty thermistor. A sign of a faulty thermistor is if your pool heater shuts off before reaching temp that you set.

sta rite pool heater thermistor

The temperature display will also become too high or too low if you have a bad thermistor.

The service heater light will be on and you’d also see the red light next to the following – AFS, THERMISTOR, AGS, HLS, PS, or SFS. The error code E01 also indicates a bad thermistor.


The only solution for a faulty thermistor is to replace it with a new one. Follow these steps to replace the thermistor:

  • Shut down your heater and make sure the power connections are off.
  • Unscrew the drain plugs and drain water from the heater.
  • Take out the front access panel by unscrewing the 4 bolts.
  • Pull out the control box by removing 2 bolts.
  • Unplug the connection of the Thermistor with the Ignition Control Panel.
  • Take the thermistor out using the heater chassis hole.
  • Unscrew the bolts holding the thermistor from the inlet side of the manifold and pull it out.
  • Put the new thermistor in place of the old one. 

Now, you have changed the thermistor. All you need to do is put your heater back together and you’re good to go.

If it was the main reason behind the heater shutting off, putting a functional one in its place will do the job and get your heater back to normal.

3. Ignition Issues

You can learn a lot about what causes the heater to shut off by keeping a close eye on the Sta Rite pool heater error codes. When the heater won’t stay on because of ignition issues, it’ll display the E05 error code.

This problem occurs when the heater hasn’t been properly maintained or when someone tries to use it after a long period of rest. It can be due to a dirty ignitor, or a faulty sensor.


Follow these steps to solve the ignition issues in pool heaters:

  • Turn off the power supply to the heater.
  • Use sandpaper and clean the ignitor with it.
  • If it still doesn’t work, replace it with a new one.
  • Inspect the sensor and replace it if has gone bad.
  • Make sure the intake and outtake venting system of the heater is clean.

The E05 error code should go away when you turn the heater back on if you’ve properly followed all the steps.

Your heater will ignite and run perfectly from now on if the problem was caused by ignition issues.

4. Bad Thermal Regulator

The thermal regulator is located at the bottom of the bolt in your heater. It acts as a safety mechanism to prevent the heater from overheating.

If the thermal regulator has gone bad, it could cause the heater to shut off. It has a spring that’s supposed to open up when the water reaches above 120 degrees.

You can easily inspect if the thermal regulator is working properly or not by heating it at the bottom using a lighter or putting it in boiling water.

If the spring opens up when you do that, the thermal regulator is okay. But it has gone bad if it doesn’t open up.


The E02 error code shows that you have a bad thermal regulator. If the manual inspection along with the error code shows that you have a faulty thermal regulator, you need to replace it with a new one.

5. Wiring Issues

Oftentimes, the main reason why your heater would shut off is because of faulty wiring. It’s not uncommon for people to find that a mouse nest is built inside their heater when they open it up.

Not only do they cause a short circuit at times but these little rats also tend to chew off wires from your heater and cause it to shut off.


Inspect your heater thoroughly to make sure that the wiring is fine. Don’t be surprised if you find a mouse nest and bits of chewed wire in it. Clean the mess and get the wiring fixed to solve this issue.

6. Malfunctioning Blower Fan

If you’re wondering why is my pool heater turning on and off, a faulty blower fan could be the reason behind it. When the fan malfunctions, you’ll hear unusual noises coming from the heater before it shuts off.

The display panel will show Error Code E04 when there’s a malfunctioning blower fan.


The two main things you need to check to resolve a malfunctioning blower fan issue are the airflow switch and the motor of the fan. If either of them is faulty, you need to replace them.

Here is how you can replace the airflow switch in the heater:

  • Shut off the heater and disconnect all power sources.
  • Access the lower enclosure by unscrewing it.
  • Identify the terminal board holding box and unscrew it.
  • You’ll see the airflow sensor switch now.
  • Unscrew it and remove the wirings connected to it.
  • Put the new airflow switch back in and connect it with all the wirings.

Once that’s done, put everything back together. Your airflow switch sensor is replaced and your heater will run fine now if it was the issue.

Here is how you can replace the blower motor in your heater:

  • Turn off the heater. Locate the control panel of the blower motor.
  • Unscrew the motor & unplug the wiring connected to the motor.
  • Take out the motor. Then, put the new motor back in.
  • Connect the wiring.

You have now replaced the blower motor successfully. Put everything back together and test your heater to see if everything is okay.

If not, keep following this Sta Rite pool heater troubleshooting to find out what’s causing the issue.

7. Leaking Cannister

The most dangerous reason that could cause your heater to turn off is a leaking canister. Inspect your heater by removing the bottom bolt of the manifold and see if any water comes off.

If water is leaking from the canister, it means that you have a bad heat exchanger.


Unfortunately, your heater has served its time if the heat exchanger has gone bad and it’s leaking water. You’re gonna have to replace your heater with a new one as the current one is most likely done and cannot be salvaged.


Why is my Sta Rite pool heater not turning on?

The most common reasons for the Sta Rite heater not turning on are actually issues with the system and not the heater. Check your filter and make sure the gas supply is turned on before working on the heater.

How do you reset the control board on your Sta Rite heater?

Turn off the breaker connected to the heater. Wait for ten seconds and turn it back on. That’ll reset the control board on the Sta Rite heaters.

How do you know if the flow of water is less in Sta Rite heaters?

When the flow of water is low, the SERVICE SYSTEM light will be on instead of the SERVICE HEATER light. Check the pump, filters, and skimmer baskets and make sure they’re clean for the heater to get proper flow.

What is the temperature range on Sta Rite heaters?

Sta Rite heaters come with a temperature of 78 degrees for the pool and 100 degrees for the spa by default. The minimum you can bring the temperature down to is 68 degrees and the highest is 104 degrees.


Now you know the main reasons why the Sta Rite pool heater keeps shutting off and what you can do to fix the issues. Properly maintaining the heater will prevent these issues from happening in the long run.

We hope this guide will help you find out the exact problem that’s causing your heater to shut off and help you fix it. Let us know if you have any more questions about Sta Rite Pool Heaters by dropping a comment below.

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 “Sta Rite Pool Heater Keeps Shutting Off [7 Easy Solutions]”

  1. This is no help. My starite pool heater goes on for a couple of minutes then shuts down with no error codes. Please explain why. The temperatures gauge does not spike the stack temperature is at 280. So why is this happening.

    • Hi Vytis

      Your Sta Rite pool heater shuts off after a few minutes may be due to one or more reasons like inadequate water flow to a dirty cartridge filter, closed valve, faulty thermistor, ignition issues, a bad thermal regulator, wiring issues, a malfunctioning blower fan, and a leaking canister.

      Well, to fix the problem, check all the above-mentioned issues one by one to find out the main culprit behind the shutting-off issue. Then fix it following our solution guide in the article.

      Hopefully, you will get the solution.

      Wish you all the best!


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