Display shows FLO or FL1, the heater is disabled, and pumps may still run.

Safety first: Turn off power at the breaker before opening the equipment bay or loosening unions.

• 1. Clean or remove filters:
  • Remove filter cartridges and rinse them thoroughly.
  • Run the spa briefly without filters to see if FLO clears (do not leave filters out long-term).
• 2. Bleed air from the system:
  • Loosen the union on the circulation pump until air and water escape, then retighten.
  • Repeat on heater unions if necessary.
• 3. Locate the flow switch:
  • Find the flow or pressure switch in the plumbing near the heater.
  • Check that the arrow on the body aligns with the water flow direction.
• 4. Inspect the wiring:
  • Ensure the flow switch cable is firmly connected to the control board.
• 5. Test the switch (qualified person):
  • With the pump running, a technician can test continuity across the flow switch terminals.
  • If the switch remains open with good flow, replace the flow switch.
• 6. If FLO persists with a new switch and clean filters: The circulation pump may be underperforming or the control board input may be faulty. Have a spa technician evaluate.