F4 error and spa pumps may not start or may shut off unexpectedly

Safety first: Turn off power at the breaker. Do not work on live electrical circuits.

• 1. Inspect Pump 1 operation:
  • With power ON, briefly try to start Pump 1 from the topside panel.
  • Listen for humming, clicking, or tripping. Then turn power OFF again.
• 2. Check for mechanical blockage:
  • Open the equipment bay and locate Pump 1 (usually the primary jet pump).
  • Verify that slice valves are open and that there are no visible obstructions in the suction area inside the spa.
  • Try rotating the pump shaft (via rear fan or coupling) by hand with power OFF; if it is seized, the pump may need replacement.
• 3. Inspect wiring:
  • Confirm that the pump’s power cord is firmly plugged into the correct socket on the control pack.
  • Look for burned connectors, discoloration, or melted insulation.
• 4. Test without load (technician level):
  • A qualified person can disconnect Pump 1 and see if F4 clears when the system is powered without the pump.
  • If F4 disappears with the pump unplugged, the pump is likely defective.
  • If F4 remains, the control board output for Pump 1 may be faulty.
• 5. Replace components as needed:
  • Replace Pump 1 if seized or shorted.
  • If the pump tests good but F4 persists, have a technician evaluate and possibly replace the main control board.