F10 code displayed; spa may not start heating cycle or may shut down shortly after starting.
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
Shock hazard: Turn off power at the breaker before loosening any unions or fittings.
- Check valves: Confirm that all Hanscraft slice valves on both sides of the heater and pumps are fully open.
- Bleed air from heater: Loosen the unions on each end of the heater tube slightly until water (and trapped air) begins to escape, then retighten. Place a towel underneath to catch water.
- Clean or remove filter: Temporarily remove the filter cartridge and run the spa briefly to see if flow improves and the error clears. If it does, replace or deep-clean the filter.
- Verify circulation pump operation: Ensure the circulation pump starts when the spa calls for heat. If it does not run, the pump or its relay may have failed.
Do not operate the heater without confirmed water flow. Persistent F10 errors require inspection of the circulation system and heater by a qualified technician.
Repair Difficulty
Required Part
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