Controller for Pahlén pool pump displays E04 and pump will not run

Safety first: This involves mains voltage. Only qualified persons should open electrical panels. Always isolate power at the main breaker and verify with a meter before touching wiring.

• Visual inspection: With power off, open the Pahlén control panel or junction box. Look for loose wires, burnt terminals, or discoloration at the pump contactor and terminal block.
• Tighten connections: Using an insulated screwdriver, gently tighten all phase and neutral terminals feeding the Pahlén pump. Do not overtighten to the point of damaging terminals.
• Check fuses: If the system uses individual fuses for each phase, test or replace any blown fuses with the correct rating specified by Pahlén.
• Verify supply: With a multimeter and appropriate training, confirm that all three phases are present at the pump input when the system is energized.
• Reset error: After correcting any supply issues, reset the controller and observe whether E04 clears and the pump starts normally.

If you are not trained in electrical work, contact a licensed electrician or Pahlén service partner to resolve E04 safely.