Display shows COL or COOL; spa stops heating and may run pumps to circulate cooler water.

Safety: In freezing weather, protect the spa from ice damage. Do not drain the spa if temperatures are below freezing unless you fully winterize it.

• Step 1 – Confirm water temperature: Use a separate thermometer to verify actual water temperature. If the water is truly very cold, allow the spa to run; the system may be in a protective mode.
• Step 2 – Check for recent refill: If you just refilled with cold tap water, COL may appear until the spa warms up. Leave the cover closed and allow several hours for heating.
• Step 3 – Inspect sensor: If the displayed temperature is much lower than actual, inspect the temperature sensor and its wiring at the Catalina control pack. Loose or corroded connections can cause false low readings.
• Step 4 – Power reset: Turn off the breaker for 5 minutes, then restore. If COL persists with normal water temperature, the sensor may be out of calibration and should be replaced.

If you are in a freezing climate and the spa will not run pumps or heat, contact a technician immediately to prevent freeze damage.