F9
Poolex Communication Fault Between Display Panel and Main Control Board

Poolex pool heater displays F9 and will not start; sometimes occurs after a storm or power surge.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Loose communication cable between Poolex keypad and main PCB, Damaged RJ-type connector or ribbon cable, Faulty display board, Faulty main control board

How to Fix / Troubleshooting

Safety: Disconnect power before opening the front panel or control box.

Steps:

  • Inspect communication cable: Locate the cable linking the user interface (display) to the main control board. Check for cuts, pinches, or burn marks.
  • Reseat connectors: Unplug and firmly reinsert the connectors at both ends. Ensure they click into place.
  • Check for moisture: Look for condensation or water ingress in the control panel. Dry thoroughly and improve weather protection if needed.
  • Power cycle: Restore power and see if F9 clears.

Component replacement:

  • If the cable is damaged, replace it with a Poolex control panel communication harness of the same type.
  • If F9 persists, either the display board or main control board may be defective. A technician can swap-test or measure signals to identify the faulty board.
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Repair Difficulty

Medium 3/5

Required Part

Control Panel Communication Cable
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