Manual

INSTALLATION & OPERATION MANUAL
FFD, FFDR, FFDRA Models
Fan Filter Unit IOM
Installation & Operation
ON/OFF Switch - Speed/Airflow Adjustment
Speed Control Adjustment
Airflow/speed is adjusted by rotating the knob (See figure above):
Clockwise  Lowers the speed
Counter-Clockwise Increases the speed
Fully rotating the speed control knob to the left or counter-clockwise will turn the unit off.
Note : When turning the unit “ON” from the “OFF” position of the speed control, the fan
is at the highest speed. Turning the speed control knob clockwise will lower the airflow.
Optional Speed Control
For units equipped with a three-position rotary switch, it is located on the side of the
electrical box. (See figure below)
Recommended fan speed during initial start-up and operation is the “LOW” speed. As
airflow eventually decreases due to filter loading, fan speed may be increased by
moving the rocker switch to the top or “MEDIUM” position, and finally to the “HIGH”
position. Periodic airflow velocity readings (per IEST Reccommended Practices)
should be conducted to determine the filter condition and appropriate fan speed
setting.
5
All units are equipped with a speed control enabling adjustment of airflow at any setting
within the recommended performance range. The speed control knob is located on the
side of the electrical box, adjacent to the on/off switch.
ON/OFF SwitchElectrical EntranceSpeed Control
ON/OFF SwitchElectrical Entrance3-Speed Switch