Display shows COL or COOL, heater does not run and spa may run pumps periodically; water is below set temperature.

Safety first: Ensure GFCI protection is working properly before extended heating in cold conditions.

• Verify water level and refill: After a fresh fill with cold water, COL is normal until the spa warms up. Confirm water level is correct.
• Allow time to heat: Close the cover and allow the spa to run for several hours. The COL message should clear as the water approaches the set temperature.
• Check set temperature: Confirm the set temperature is at your desired level (e.g., 37–40°C). Increase if it was set very low.
• Inspect temperature sensor: If COL persists even when water feels warm, the sensor may be reading too low. Inspect and test the Arctic Spas temperature sensor and replace if out of spec.
• Cold climate tips: In very cold weather, ensure the cabinet insulation is intact and the cover seals well to prevent excessive heat loss.