Display shows COOL or COLD and heater does not run until water warms slightly.

Safety first: Ensure GFCI protection is working before operating the spa in freezing conditions.

• Verify actual temperature: Use a separate thermometer to confirm water temperature.
• Allow spa to circulate: The spa may run pumps without heat until water reaches a minimum temperature. Keep the cover on to retain heat.
• Check temp sensor: If the displayed temperature is much lower than actual, the sensor may be faulty and should be replaced.
• Do not override freeze protection: This mode protects plumbing from freezing; allow the system to manage circulation automatically.