FloAire DMUA - Manual (Page 19)

19
Pulley Setscrew Torque
Thread Size Torque (IN/Lb)
No. 10 (bushing) 32
1/4” (bushing) 72
5/16” 130
OPERATION
Prior to starting up or operating the ventilator, check all fasteners for tightness. In particular, check the set
screw in the wheel hub, bearings and the fan sheaves (pulleys). With power to the fan OFF or prior to
connecting ventilator to power, turn the fan wheel by hand to be sure it is not striking the inlet or any
obstacles. Re-center if necessary.
Start Up
Special Tools Required

AC Voltage Meter

Tachometer

Amperage Meter

Standard Hand Tools
Start Up Procedure
1. Check all electrical connections for tightness and continuity.
2. Check pulley alignment and belt tension as described below for belt drive fans.
3. Inspect the condition of the damper and damper linkage, if provided.
4. Inspect the air-stream for obstructions or debris in wheel.
5. Compare the supplied voltage
with the fan’s nameplate voltage. If this does not match, correct
the problem.
6. Start the fan up, by turning the external disconnect to the ON position, and shut it OFF
immediately to check rotation of the wheel with the directional arrow on the blower scroll.
Reversed rotation will result in poor air performance, motor overloading and possible burnout.
For units equipped with a single-phase motor check the motor wiring diagram to change rotation.
For 3-phase motors, any two power leads can be interchanged to reverse motor direction.
7. When the fan is started up, observe the operation and check for any unusual noises.
8. Switch the external disconnect back to the ON position and with the air system in full operation
and all ducts attached, measure the system airflow. Motor sheave (pulley) is variable pitch, and
allows for an increase or decrease of the fan RPM to adjust the airflow, as shown in the
illustration below. For your convenience, a RPM chart is included in the following pages. If the
fan is a direct drive version, it may have a speed control to adjust speed.
9. Once the proper airflow is achieved, measure and record the fan speed with a reliable
tachometer. Caution - Excessive speed will result in motor overloading or bearing failure.
Do not set fan RPMs higher than specified in the maximum RPM chart. See the
troubleshooting guide for more information.
10. Measure and record the voltage and amperage to the motor and compare with the motor
nameplate to determine if the motor is operating under safe load condition.
11. Once the rpm of the ventilator has been properly set, disconnect power and recheck belt tension
and pulley alignment as described below.
Pulley Adjustment Illustration