Display shows FLO or FL and heater will not turn on; sometimes pumps run but there is weak or no water movement from heater return jets.

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

• Step 1 – Clean or remove filter: Remove the filter cartridge from the skimmer. 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 error clears.
• Step 2 – Check water level: Ensure the water level is at least halfway up the skimmer opening. Low water can draw air into the system and cause flow errors.
• Step 3 – Bleed air from pump: Open the equipment compartment. Slightly loosen the union on the suction side of the circulation or primary pump until water seeps out and air stops, then retighten. Repeat on the discharge side if needed.
• Step 4 – Inspect slice valves: Verify that all slice (gate) valves on either side of the pump and heater are fully pulled up and locked. A partially closed valve will restrict flow.
• Step 5 – Test flow/pressure switch: Locate the flow or pressure switch on the heater manifold. Check that its wires are firmly connected. With power off, inspect for debris around the switch paddle (if accessible). Do not bypass the switch for normal operation.
• Step 6 – Reset and observe: Restore power and run the spa in standard mode. If FLO persists with good flow visible, the flow switch may be stuck or failed and should be replaced.