Display shows COL or COOL, the heater does not run, and the spa may run pumps in freeze-protection mode.

Safety: Ensure the spa remains powered during freezing conditions to prevent plumbing damage.

• Verify actual water temperature: Use a separate thermometer to confirm the water temperature. If it is near freezing, allow the spa to run; the system is protecting itself.
• Check cover and insulation: Make sure the QCA Spas cover is in good condition and sealed to retain heat. Replace damaged covers.
• Sensor calibration: If the displayed temperature is much lower than the actual temperature, inspect and replace the temperature sensor.