FLC
Caldera Spas
Flow Switch Stuck Closed / Shorted
Display shows “FLC” (flow closed) even when pump is off; heater may not operate correctly.
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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.
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Possible Causes
Stuck flow switch paddle, Shorted flow switch contacts, Incorrectly wired flow switch, Faulty IQ control board input circuit
How to Fix / Troubleshooting
Safety first: Turn off power at the GFCI breaker.
- Inspect wiring: Locate the flow switch and verify that the wires are connected to the correct terminals on the IQ control board as per the wiring diagram.
- Check for physical sticking: Remove the flow switch from the plumbing (after draining or clamping lines). Inspect the paddle or sensor for debris or scale buildup and clean gently.
- Continuity test (advanced): With the switch removed and disconnected, use a multimeter to check that the switch is open when no flow is present. If it reads closed (shorted) constantly, it is defective.
- Replace if faulty: Install a new Caldera-compatible flow switch, ensuring the arrow on the body points in the direction of water flow.
- If FLC persists with a new switch: The control board’s flow switch input may be damaged and the IQ control board may need replacement by a technician.
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Repair Difficulty
Hard
4/5
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