Control panel displays FLO or FL, jets may not run, heater will not turn on, possible blinking light on topside control.

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

• Check water level: Ensure the water level is above all skimmer openings and filter intakes. Top off if low, then reset power.
• 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 the filter well cover in place) to see if the FLO code clears. If it clears, replace the filter cartridge.
• Bleed air from lines: After a refill, air can be trapped in the circulation pump. With power OFF, open the equipment compartment, locate the circulation pump on the Aquaterra Spas equipment pack, and slightly loosen the pump union until water seeps out and air stops. Retighten, then restore power.
• Check circulation pump operation: With power restored, verify that the small circulation pump is running (you should feel vibration and see gentle water movement at the heater return). If it is not running, the pump or control board may be faulty.
• Inspect flow/pressure switch: Locate the flow or pressure switch near the heater tube on the Balboa-style control pack used in many Aquaterra Spas. Check that the wires are firmly connected and that there are no kinks in the vinyl tubing (if pressure-style). Do not bypass the switch; if defective, replace it.

If the FLO code persists after filter cleaning, air bleeding, and confirming pump operation, the flow switch or circulation pump likely needs replacement and a qualified spa technician is recommended.