Display shows FL2 or FLO2 and spa may run pumps but heater remains off
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: Shut off power at the GFCI breaker before touching any wiring or plumbing.
FL2/FLO2 usually means the control system sees the flow switch as closed when it should be open (no flow), which is a safety concern.
- Locate the flow switch: Find the flow switch assembly in the plumbing near the heater on your American Whirlpool spa.
- Inspect wiring: Check the cable from the flow switch to the control pack for cuts, abrasions, or signs of rodents. Ensure the connector is firmly seated on the control board.
- Check orientation: Verify the arrow on the flow switch body matches the direction of water flow and that the switch is installed horizontally if specified by the manufacturer.
- Test with power on: Restore power and, with pumps off, observe whether the FL2 code is present. If the system still thinks there is flow when pumps are off, the switch is likely stuck closed or shorted.
- Replace flow switch: Turn power off again, drain or clamp lines as needed, remove the old flow switch, and install a compatible American Whirlpool flow switch, using new gaskets or O‑rings and proper thread sealant where required.
If a new flow switch does not clear FL2, the control board's flow input circuit may be defective and should be tested by a spa technician.