Display shows COL or COOL; spa indicates water is too cold and may run pumps but not heater immediately.

Safety: Ensure the spa is filled and all plumbing is intact before running pumps in freezing conditions.

• Step 1 – Verify water temperature: Use an external thermometer to confirm actual water temperature.
• Step 2 – Allow spa to warm gradually: Keep the cover closed and let the spa run. The controller may delay heating until it confirms stable sensor readings.
• Step 3 – Check sensors: If COL persists even when water is warm, inspect the temperature sensor for proper placement and damage.

COL is usually informational. If the spa never begins heating, a sensor or control issue may be present and should be diagnosed.