Display shows COOL, heater does not run until water warms slightly

Safety: Normal protective function; no internal repair usually needed.

• Allow spa to warm: Keep the cover on the Villeroy & Boch spa and allow the system to gradually warm the water. COOL will clear automatically.
• Check set temperature: Ensure the set temperature is appropriate and not extremely low.
• Verify circulation: Confirm that the circulation pump is running to help distribute heat.

If COOL remains for an extended period and the spa does not heat, investigate heater and sensor faults.