Display shows COL or COOL and heater does not run; spa may be in a protection mode after an overheat or power event.

Safety: Ensure water temperature is safe before entering the spa.

• Step 1 – Verify water temperature: Use an external thermometer to confirm actual water temperature. If water is normal but COL persists, it may be a logic or sensor issue.
• Step 2 – Allow cool-down: Remove the cover and run the jets to help equalize water temperature. Some AquaRest control packs require a cool-down period before reheating.
• Step 3 – Check mode and setpoint: On the topside control, verify the spa is not in an economy or sleep mode that delays heating. Confirm the set temperature is above current water temperature.
• Step 4 – Power reset: Turn off the GFCI breaker for 5 minutes, then restore power to clear any temporary logic lockout.

If COL remains with normal water temperature and correct settings, the temperature sensor or control board may need diagnosis.