Display shows FLO or FL, jets may not run, heater will not turn on, and spa may shut down after a short period.

Safety first: Turn off power to the spa at the GFCI breaker before opening any equipment area or removing filters.

• Check water level: Ensure the water level is at least halfway up the skimmer opening. Top off if low, then reset power.
• Clean or remove filter: Remove the filter cartridge(s) from the filter well. Rinse thoroughly with a garden hose from top to bottom. For testing, run the spa briefly with the filter removed to see if the FLO code clears (do not leave it running long-term without a filter).
• Bleed air from lines: If the spa was recently drained/refilled, loosen the union on the circulation pump or main jet pump slightly until water seeps out to release trapped air, then retighten. Restore power and test.
• Inspect flow/pressure switch: Locate the flow or pressure switch on the heater plumbing (often a small tee with two wires). Check for loose or corroded connectors. With power off, disconnect and reconnect the spade terminals. If FLO persists with clean filters and proper water level, the switch may be stuck open and require replacement.
• Check circulation pump operation: Verify that the Clearwater Spas circulation pump is running during a heat or filter cycle. If it hums but does not move water, it may be air-locked or failed.

If the FLO code remains after these steps, contact a qualified spa technician to test the flow switch and circulation pump electrically.