Controller displays PMP or PUMP and solar heating is disabled; controller indicates no pump operation even though the pump may be running.

Safety first: Turn off all power at the breaker panel before opening any control boxes. Verify with a non-contact voltage tester.

• Review wiring diagram: Compare the actual wiring between the main pump timer/automation and the Heliocol-compatible solar controller to the installation manual. Correct any miswired terminals.
• Inspect pump relay: Open the solar controller and locate the pump relay. Check for burned contacts, melted plastic, or loose spade connectors. Tighten or replace connectors as needed.
• Verify pump sense: If the controller uses a power-sensing input to detect pump operation, ensure the sense wire is connected to the correct load side of the pump circuit.
• Test relay function: With power restored and using proper electrical safety, command solar on and listen for the relay click. If there is no click and no output, the relay may be defective and require replacement.
• Consider technician: If you are not comfortable working with line voltage, contact a qualified pool electrician to replace the relay or correct wiring.