Display alternates between FLC and temperature reading; spa may heat intermittently or not at all.

Safety: Disconnect power at the breaker before working on the control pack or flow switch.

• Step 1 – Inspect wiring: Open the equipment bay and locate the flow switch on the heater manifold. Trace its cable to the control board and ensure it is plugged into the correct labeled connector and not pinched or damaged.
• Step 2 – Check for debris: If the flow switch has a removable section, carefully remove it and inspect the paddle or plunger for scale or debris that could hold it closed. Clean gently and reinstall with new seals if needed.
• Step 3 – Verify orientation: Confirm the arrow on the flow switch body matches the direction of water flow. Incorrect installation can cause false readings.
• Step 4 – Reset power: Restore power and observe whether FLC clears. If the error returns immediately even when the pump is off, the switch contacts may be shorted.
• Step 5 – Replace flow switch: If wiring and orientation are correct and FLC persists, replace the flow switch with a compatible AquaRest part.

If a new switch does not resolve the issue, the control board input circuit may be defective and should be tested by a professional.