Display shows FL1, heater is disabled, jets may still operate but spa will not heat.
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: Turn off power at the GFCI breaker before touching any wiring or plumbing unions.
- Clean or bypass filter: Remove and rinse the Evolution Spas filter cartridge. Try running the spa briefly without the filter to see if FL1 clears. If it does, replace the filter.
- Bleed air from heater line: With power OFF, slightly loosen the union at the heater inlet until air escapes and water begins to seep, then retighten. This helps clear air locks that can prevent the flow switch from closing.
- Inspect flow switch: Locate the flow switch in the plumbing near the heater tube. Check that the wires are firmly connected to the control pack terminals and that there is no visible damage or kinks in the cable.
- Check for adequate circulation: Restore power and run the pump. Look for strong water movement at the heater return. Weak flow may indicate a failing circulation pump.
If FL1 remains after these steps, the flow switch itself may be defective and should be replaced with a compatible Evolution Spas flow switch. If you are unsure about electrical testing, contact a professional technician.