Display shows FLO or FL1 and heater will not run; may show intermittent heating

Safety: Turn off power at the GFCI breaker before opening unions or removing filters.

• Remove and clean filters: Take out all filters and rinse thoroughly. For testing, leave filters out and restore power to see if FLO clears.
• Check water level: Ensure water is at the proper level so skimmers are not drawing air.
• Bleed air from pumps: With power OFF, slightly loosen the unions on the circulation pump and main pump(s) until water seeps out and air escapes, then retighten.
• Inspect flow switch: Locate the flow switch in the plumbing near the heater (a small tee with two wires). Check that the wires are firmly connected and not damaged.
• Test flow switch (basic): With power OFF, gently tap the flow switch body to free a stuck paddle. Restore power and see if FLO clears when the circulation pump runs.
• Check circulation pump operation: When the spa calls for heat, verify that the circulation pump is running and you see a steady stream from the circulation return. If the pump is silent or only hums, it may need replacement.

If FLO persists after filter cleaning and air bleeding, the flow switch or circulation pump is likely defective and should be replaced with Artesian-compatible parts.