Display shows COL or COOL, heater does not run, pumps may circulate water only.

Note: COL/COOL is often informational, not a fault, indicating the spa is protecting itself from freezing.

• Allow spa to warm: After a refill with cold water, give the spa several hours to heat. Ensure the cover is on to retain heat.
• Verify set temperature: Confirm the set temperature is above the current water temperature and that the spa is not in sleep/low heat mode.
• Check sensors: If COL persists even when water is warm, inspect the temperature sensor for proper seating and damage.

If the spa will not heat out of COL mode despite warm water and correct settings, have a technician test the temperature sensor and control board.