Control panel displays FLO and spa will not heat; jets may run briefly then shut off.

Safety first: Turn off power at the GFCI breaker before opening the equipment compartment or removing filters.

Step-by-step:

• 1. Check water level: Ensure water is above all jets and at the recommended fill line. Low water can cause a FLO error.
• 2. Clean or remove filter: Remove the filter cartridge from the filter well. Rinse thoroughly with a garden hose from top to bottom. For testing, run the spa briefly without the filter (with power restored) to see if FLO clears. If it does, replace the filter.
• 3. Bleed air from lines: With power off, loosen the union on the circulation pump or heater slightly until water seeps out, then retighten. This releases trapped air that can block flow.
• 4. Verify valves are open: In the equipment bay, confirm all slice/ball valves on suction and return lines are fully open and not stuck mid-position.
• 5. Test circulation pump: Restore power and observe if the small circulation pump runs smoothly and water is visibly moving in the spa. If the pump hums but does not move water, it may be seized or failing.

If FLO persists after filter replacement, air bleeding, and valve checks, the circulation pump or flow switch may need replacement. Contact a qualified spa technician if you are not comfortable working on live electrical components.