E5
Poolex Main Control Board Fault / EEPROM Error

Poolex pool heater shows E5 and will not start; often after a lightning storm or 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

Corrupted firmware on Poolex main PCB, Power surge damage, Internal component failure on control board, Loose board connectors

How to Fix / Troubleshooting

Safety: Disconnect power before opening the control box.

Steps:

  • Power reset: Turn off power for 5–10 minutes to fully discharge the electronics, then restart.
  • Inspect board: Look for burn marks, swollen components, or water ingress on the main PCB.
  • Check connectors: Reseat all multi-pin connectors on the board.

If E5 persists, the main control board likely needs replacement. Order the correct Poolex main control PCB for your model and have it installed by a qualified technician to avoid miswiring.

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Repair Difficulty

Hard 4/5

Required Part

Main Control Board
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