Display shows COL or COOL and spa runs pumps but does not heat to set temperature.

Safety: In freezing conditions, do not drain the spa unless you can fully winterize it immediately.

• Allow spa to warm gradually: If you have just refilled with cold water, COL is normal. Keep the cover on and allow the RivieraPool heater to bring the water up slowly.
• Check sensor placement: Ensure the temperature sensor is properly seated in its well or shell fitting and not exposed to outside air.
• Verify heater operation: Listen for the heater relay click and feel the heater tube for gentle warmth after 10–15 minutes of heating demand.
• Freeze protection: In very cold weather, the spa may cycle pumps automatically to prevent freezing. This is normal. Ensure power remains on and the water level is maintained.
• Sensor replacement: If COL persists even when water is clearly warm, the RivieraPool temperature sensor may be misreading and should be replaced.