Display shows COOL; spa is below set temperature and may temporarily suspend heating.

Safety first: Keep power ON to allow the spa to heat and prevent freezing in cold climates.

• 1. Confirm set temperature: Ensure the set temperature is higher than the current water temperature.
• 2. Allow time to recover: After a refill or long use with cover off, the spa may need several hours to reach set temperature.
• 3. Check for other error codes: If COOL appears along with FLO, HFL, or sensor errors, address those issues first.
• When to call a technician: If the spa never heats above COOL and no other codes are present, the heater or control board may require diagnosis.