COL
Hot Spring Cold Water Protection / Freeze Condition Detected

Display shows “COL”; spa will not heat and may run pumps to cool water.

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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

Water temperature sensor reading below safe threshold, Spa left unheated in cold weather, Sensor out of calibration, Low water level causing false cold reading

How to Fix / Troubleshooting

Safety first: Ensure power remains ON in freezing conditions to allow freeze protection to operate.

  • Verify actual water temperature: Use a separate thermometer. If water is truly near freezing, keep the cover on and allow the spa to run its protection cycle.
  • Check water level: Low water can expose sensors and cause incorrect readings. Top off the spa.
  • Inspect temperature sensor: If the water is not actually cold but COL is displayed, inspect the temperature thermistor and its wiring for damage.
  • Reset after warming: Once water is above freezing and sensors are verified, power-cycle the spa to clear the code.

If COL persists in normal temperatures, the temperature sensor or control board may need replacement.

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Repair Difficulty

Medium 3/5

Required Part

Water Temperature Thermistor
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