Display shows COL or COOL and heater does not run; spa may be in freeze protection mode.

Note: COL is usually informational, not a failure, but can indicate sensor issues if conditions are normal.

• Check actual water temperature: Use a separate thermometer to verify the spa water temperature.
• Allow warm-up: If the spa was just filled with cold water, allow several hours for the heater to bring the temperature up. Keep the cover on to retain heat.
• Verify sensor accuracy: If the display shows COL but the water is warm, the temperature sensor may be out of calibration. Compare displayed temp to your thermometer.
• Inspect sensor wiring: With power off, check the water temp sensor harness and connector on the MAAX control pack.
• Replace sensor if inaccurate: Install a new MAAX-compatible water temperature sensor if readings are consistently wrong.