Introduction:

The Vent PAK has been designed to provide outside ventilation air flow through a computer or electronic equipment enclosure in the event of a power outage or air conditioner failure. Sequence of Operation:

1. AC and DC power supplies are normal; enclosure temperature is below designated set point.

This is considered the “normal” condition, therefore the fan is not required to operate and the louvers remain in a closed position.

2. AC and DC Power supplies are normal, enclosure air temperature rises above the set point due to the possibility of air conditioner failure.

In this mode, the thermostat contacts open, the fan will operate and the louvers will open.

3. AC power supply fails; 48VDC power supply is normal. In this mode, the fan will operate and the louvers will open.

When the primary AC power supply is restored, the fan will stop operation, the louvers will close and the timer will energize. If after a factory set time period of 1000 seconds or 16.67 minutes (adjustable), the thermostat contact is closed, indicating a satisfactory enclosure temperature, the fan will remain off and the louvers will remain closed. If after the factory set time period the thermostat contact is open, indicating an enclosure temperature above the thermostat set point, the fan will begin operation and the louvers will open.

Note: This timed output can be reset by momentarily interrupting power to the 48VDC power supply circuit. This will increase the time delay another 1000 seconds.

DDB Unlimited, Inc. / 800-753-8459 / Wynnewood, Ok 73098