Pentair Pool Heater Display Not Working [3 Easy Fixes]

Your Pentair pool heater display not working can be a result of a lack of power supply, a blown fuse, or a defective control board. Read our Pentair pool heater troubleshooting guide to solve this issue ASAP. 

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Pentair Pool Heater Display Not Working [3 Easy Fixes]

In this section, we will explore the causes behind your heater display not working in greater depth as well as provide you with easy solutions. 

1. Lack Of Power Supply

The heater receives a regular voltage of 120 or 240 volts, which is wired to the heater transformer, which decreases (or converts) the current to 25 volts. This electricity is transmitted to the ignition control, which is an electronic switching device. 

This serves as a conduit or distributor between the control circuit and the rest of the system. The current passes via the safety and control circuit from here. The transformer is crucial in this situation.


Check the transformer’s input line voltage. Depending on how it was initially wired, it must be 120V or 240V. To precisely verify the voltage, you’ll need a multimeter or a voltage meter.

If you have voltage going to the transformer but no voltage coming out, it’s most likely the transformer that has to be replaced.

Check the breakers, the pump switch, or the heater power supply if there is no power going to the transformer.

Also, investigate the Ignition control module if you have power to the transformer and power exiting the transformer but no lights or display.

2. Blown Fuse

If the Fireman’s Switch or the fuse on your Pentair pool heater has blown, you will not have a working display. 


Check on the glass fuse. In case the string inside the fuse is broken at a point, the fuse is blown. Get a new Fireman’s Switch to replace the old one. Your pool heater should start working normally.

3. Defective Control Board

Your Temperature Display is part of the control board. It is a possibility that your control board has gone bad, causing your display to not work.


You need to replace your control board. Contact Pentair customer service to send you a new control board. With some technical experience, you can replace the control board on your own.

  • First, take off the two side covers. Then, unscrew the top cover of your Pentair. Lift the top cover, very gently as the control board is attached to it. You need to flip the cover to access it. 
  • Take a picture of all the wires that go into the control board. Try to understand where each connection is made so that you can replicate it. 
  • Remove the screws holding the old control panel in place. Screw the new control board in place. One by one, detach the wires from the old control board and move them to the new one.
  • Once you have ensured that the new control board is working fine, reinstall the top cover and the side covers. 

Watch this video for more detailed instructions. 


How to reset the Pentair pool heater?

Without a reset button, you need to reset your heater manually. First, turn it off. After waiting about 10-15 minutes, restart the heater. This will reset your Pentair pool heater. 

How do you troubleshoot the pilot light of a gas pool heater?

If the pilot won’t ignite, it’s possible that the gas pressure is low, the air supply is inadequate, or the heater isn’t venting effectively. Check the gas pressure and make any required adjustments. Then double-check that none of the vents are blocked.

What does a pressure switch do on a pool heater?

The pressure switch’s job is to make sure there is water flow before allowing the heater to turn on. For the switch to shut and allow electricity to pass through, the pool pump must be turned on and the filter must be clean.

Can you enclose a pool heater?

Heaters and heat pumps are not allowed to be enclosed. Proper airflow and exhaust venting are required for pool heaters. If the sides are enclosed, make sure the top is exposed to the sky or follow the manufacturer’s directions for proper ventilation.

How many years does a pool pump last?

You can expect a well-maintained and good-quality heat pump to last 8-12 years. However, if you’ve neglected a number of important pool services, your pump is likely to fail sooner.


Hopefully, with the help of our guide, you were able to fix your Pentair pool heater display not working. Read our article on Pentair MasterTemp 400 common problems to fix any issue you have with your Pentair 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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