Display shows COL; spa may limit heating or run pumps intermittently.

Safety first: Keep power ON in cold weather to prevent freeze damage.

• 1. Confirm water temperature: Use a thermometer to verify that the water is actually cold. If so, COL is a normal warning.
• 2. Allow time to heat: After a refill, it can take many hours for the Sundance heater to bring water to set temperature. Leave the cover on and let the spa run.
• 3. Check heater operation: Listen for the click of the heater relay and feel the heater tube after 15–20 minutes of operation (it should be warm, not hot). Ensure there is good water flow through the heater.
• 4. Inspect filters: Clean or replace the filter to ensure proper flow so the heater can operate efficiently.
• When to call a technician: If COL persists and the water does not warm after several hours, the heater, sensor, or control board may need diagnosis.