Display shows FLO or FL1 and the hot tub will not heat; jets may run briefly then stop.
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Turn off power at the GFCI breaker before opening any panels or touching internal components.
- Check water level: Ensure the water level is above all suction fittings and at least halfway up the skimmer opening. Top off if low.
- Clean or remove filter: Remove the Jacuzzi filter cartridge and rinse thoroughly with a garden hose from top to bottom. For testing, run the spa briefly without the filter (with the cover open and no bathers) to see if the FLO code clears.
- Bleed air from lines: If the spa was recently drained/refilled, loosen the union on the circulation pump or use the bleed screw (if equipped) to release trapped air until water seeps out, then retighten.
- Inspect flow/pressure switch: Locate the flow or pressure switch on the heater plumbing. Check that the wires are firmly connected and that there are no kinks in the vinyl tubing (if pressure-sensing type). Do not bypass the switch for normal use.
- Test circulation pump: Restore power and listen for the small circulation pump (Jacuzzi ProClarity/ProStream style). If it hums but does not move water, the pump may be seized and require replacement.
If FLO persists after filter cleaning and air bleeding, the flow switch or circulation pump likely needs replacement and a qualified spa technician should test continuity and current draw.