On a call for cooling (when the outside air reaches a level above the built-in thermostat set-point), the internal solenoid is powered allowing water to flow through the manifold and out through discharge nozzles. Water leaving the nozzles saturates the face and top of the CELDEK media and eventually soaks the thickness of the 12" media. A timing circuit controls the flow of water to the media, thus optimizing the amount of moisture in the media at all times. While this is occurring, there is continuous airflow through the CELDEK media, absorbing the moisture in the media.

Benefits of this type of operation are the following:

• No sump or re-cycling pump is required. Because of this, there is less bacterial build-up in the evaporative cooler and the air being delivered to the space is much healthier.
• There is a continuous wash-down of the media to keep it flushed. This lengthens the life of the media and reduces service required. This keeps scaling and particle build-up minimized.
• There is no sump drain-off required in the winter. Since there is no water reservoir, the concern about sump freezing is eliminated.