Display shows FLO or FL, heater will not turn on, spa may run pumps but water does not heat.

Safety first: Turn off power at the spa disconnect or main breaker before opening any panels. Water and electricity are dangerous together.

• Check water level: Ensure the water level is above all skimmers and suction fittings. Low water can cause low flow.
• Clean or remove the filter: Remove the filter cartridge from the filter canister. Rinse thoroughly with a garden hose from top to bottom. For testing, run the spa briefly without the filter to see if the FLO code clears. If it does, replace the filter.
• Bleed air from the system: After a refill, loosen the union on the circulation pump or heater inlet slightly to let trapped air escape until water seeps out, then retighten. Some LA Spas models have a bleed screw on the pump face—open it carefully until water flows steadily.
• Inspect the circulation pump: With the power back on, verify that the dedicated circulation pump (often a small 24‑hr pump) is running and you can feel water movement at the heater return. If the pump is hot, noisy, or not running, it may be seized or failed.
• Check the pressure/flow switch: Power off. Locate the pressure/flow switch on the heater manifold. Inspect the wires and terminals for corrosion or breaks. If adjustable, note the original setting, then slightly adjust and test. If the FLO code persists with good flow and a clean filter, the switch may need replacement.

If the FLO code remains after these steps, the circulation pump or flow/pressure switch likely needs replacement and a technician should test system pressure and current draw.