FLC
Coast Spas Flow Switch Stuck Closed / Shorted

Display shows FLC or FLOC indicating flow switch closed when it should be open; heater may be disabled.

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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 or plunger, Shorted flow switch wiring harness, Incorrect plumbing orientation causing constant flow across switch, Failed control board input circuit

How to Fix / Troubleshooting

Safety first: Disconnect power at the GFCI breaker before touching any wiring or plumbing.

  • Inspect flow switch body: Locate the flow switch on the heater plumbing. Check for visible damage, leaks, or misalignment.
  • Check wiring: Ensure the flow switch connector is fully seated on the Coast Spas control pack and that wires are not pinched or rubbed through.
  • Tap to free stuck mechanism: With power off, gently tap the flow switch housing with a non-metallic tool to free a stuck internal paddle or plunger.
  • Power cycle: Turn power off for 5 minutes, then back on. If FLC returns immediately, the switch may be shorted or the board input faulty.
  • Replace flow switch if needed: If continuity across the switch is present even with no flow (tested with a multimeter), replace the flow switch assembly.
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Repair Difficulty

Medium 3/5

Required Part

Flow Switch
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