ERR9
AO Smith Ground Fault / Leakage Current Detected

AO Smith variable-speed pool pump display shows “ERR9” and the motor does not run.

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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

Moisture inside motor or junction box, Damaged motor winding insulation, Pinched or cut power cable, Faulty internal ground connection

How to Fix / Troubleshooting

Safety Warning: A ground fault is a serious electrical hazard. If you are not qualified, contact a professional immediately.

  • Inspect external wiring: With power OFF, check the power cable and conduit for cuts, abrasions, or crushed sections. Repair or replace damaged wiring.
  • Check for moisture: Look for water inside the motor terminal box or control housing. Dry thoroughly and correct any leaks or condensation sources.
  • Insulation testing: A technician should perform a megohmmeter (megger) test between motor windings and ground. Low insulation resistance indicates a failing motor.
  • Replace motor assembly: If insulation is compromised, the safest repair is to replace the AO Smith motor assembly rather than attempting internal rewinding for residential applications.
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Repair Difficulty

Professional Required 5/5

Required Part

Motor Assembly
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