Display shows COL or COOL, heater does not run, spa indicates water is too cold to heat normally.

Safety first: Ensure power is on to allow freeze protection to operate. Do not shut off power in freezing conditions.

• 1. Verify actual water temperature: Use a thermometer to confirm the water is indeed very cold. If just refilled, the spa may need several hours to warm.
• 2. Check sensor placement: Locate the temperature sensor on the heater tube. Make sure it is fully inserted and making good contact with the heater housing or in its dry well.
• 3. Allow spa to run: Keep the cover closed and allow the circulation pump and heater to operate. The COL message should clear automatically as the water warms into the normal range.
• 4. Sensor fault check: If the display shows an unrealistically low temperature compared to a thermometer, the sensor may be failing. Replace the temperature sensor with a Coleman-compatible thermistor.
• 5. Freeze protection: In freezing weather, ensure the spa remains powered so the control pack can run pumps automatically to prevent freezing, even if COL is displayed.