Pump will not start, digital controller shows E01 immediately after power-on

Safety first: Disconnect power at the breaker and lock it out before touching the pump or control box. Never work on a wet electrical panel.

• Check for mechanical blockage: Remove the pump lid and basket. Inspect the Calpeda impeller area with a flashlight. Remove leaves, stones, cable ties, or any debris. Try to rotate the motor shaft or impeller by hand (using an insulated tool if needed). It should turn smoothly.
• Verify supply voltage: Using a multimeter, confirm that the incoming voltage at the Calpeda control box terminals matches the nameplate (e.g., 230 V single-phase or 400 V three-phase). Incorrect voltage can cause overcurrent trips.
• Inspect motor for seizure: With power off and pump uncoupled if possible, try to spin the motor fan at the rear of the Calpeda motor. If it is stiff or locked, the bearings or rotor may be seized.
• Reset overload: Many Calpeda pool pump control boxes have a manual reset button on the thermal overload relay. After resolving any blockage and allowing the motor to cool for 20–30 minutes, press the reset. Restore power and test.
• If E01 returns immediately: Disconnect the motor leads from the control box and measure winding resistance. Very low resistance or a dead short indicates a failed motor winding that requires motor replacement.

If you are not comfortable working with live electrical circuits, contact a qualified pool pump technician or electrician.