Pump controller shows E08 and motor runs very slowly or not at all

Safety first: Turn off power before tightening any electrical connections.

• Measure voltage at pump under load: With the pump running (if possible), measure voltage at the Calpeda control box input. Compare to the motor nameplate. A drop of more than 10% indicates a supply issue.
• Inspect cable size and length: Check that the cable gauge and run length meet Calpeda installation recommendations. Long runs with small cables cause significant voltage drop; upgrading the cable may be necessary.
• Tighten terminals: With power off, tighten all line and neutral terminals in the control box and at the breaker. Loose connections cause heating and voltage loss.
• Reduce circuit load: Ensure the pump is on a dedicated circuit or that other large loads (heaters, large lights) are not causing excessive drop when they start.
• Reset controller: After correcting supply issues, clear the E08 fault and test. If mains voltage remains low, contact your power provider or an electrician.