LOP
AquaCal Low Pump Speed / Flow Detected

Display shows LOP or LOW PUMP; the heater will not run.

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Possible Causes

Variable-speed pump running too slow, Pump schedule not synchronized with heater demand, Flow switch calibration mismatch, Partially clogged skimmer or pump basket

How to Fix / Troubleshooting

Safety first: Turn off the heater before changing pump settings.

  • Increase pump speed: On variable-speed pumps, raise the RPM during heating cycles to meet AquaCal's minimum flow requirement.
  • Align schedules: Ensure the pump is scheduled to run at sufficient speed whenever the AquaCal heater is enabled.
  • Clean baskets: Empty skimmer and pump baskets to restore full flow.
  • Flow switch check: If flow is visibly strong but LOP persists, the flow switch may be misaligned or failing and should be inspected and/or replaced.
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Repair Difficulty

Easy 2/5

Required Part

Flow Switch
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