COOK QMX Series Installation, Operation And Maintenance Manual page 3

Duct and Damper Installation
Efficient fan performance relies on the proper installation of inlet
and discharge ducts as well as dampers. Be sure your fan conforms
to the following guidelines and allows three duct diameter of straight
duct before placing an elbow or damper. Clearance is also required
on the inlet and outlet for maintenance such as pulley or bearing
replacement.
Non-Ducted Inlet Clearance
If your fan has an open inlet (no duct work), the fan must
be placed one effective wheel diameter away from walls and
bulkheads.
MIN
1 DIA
Non-ducted Inlet Clearance
Free Discharge
Avoid a free discharge into the plenum. This will result in lost
efficiency because it doesn't allow for a static regain.
Correct
Free Discharge
Inlet Duct Turns
For ducted inlets, allow at least three effective wheel
diameters between duct turns or elbows and the fan inlet.
Correct
Incorrect
Inlet Duct Turns
Discharge Duct Turns
Where possible, allow three duct diameters between duct
turns or elbows and the fan outlet.
Discharge Duct Turns
QMX IO&M
Incorrect
MIN
3 DIA
Correct
MIN
3 DIA
Incorrect
Wheel-to-Inlet Clearance
The correct wheel-to-inlet clearance is critical to proper fan
performance. This clearance should be verified before initial
start-up since rough handling during shipment could cause a
shift in fan components. Refer to wheel/inlet drawing below for
correct overlap.
Adjust the overlap by loosening the wheel hub and moving
the wheel along the shaft to obtain the correct value. Trim
balance as necessary following procedure (0.0785 in/sec
max).
A uniform radial gap (space between the edge of the cone
and the edge of the inlet) is obtained by loosening the inlet
cone bolts and repositioning the inlet cone.
Wheel/Inlet Overlap
SEE DETAIL A
Belt and Pulley Installation
Belt tension is determined by the sound the belts make when
the fan is first started. The belts will produce a loud squeal
which dissipates after the fan is operating at full capacity. If
belt tension is too tight or too loose, lost efficiency and damage
can occur.
Do not change the pulley pitch diameter to change
tension. This will result in a different fan speed.
1. Loosen motor plate adjustment bolts and move motor
plate in order that the belts can easily slip into the grooves
on the pulleys. Never pry, roll or force the belts over the
rim of the pulley.
2. Adjust the motor plate until proper tension is reached. For
proper tension, a deflection of approximately 1/4" per foot
of center distance should be obtained by firmly pressing
the belt. Refer to Figure 3.
3. Lock the motor plate adjustment nuts in place.
4. Ensure pulleys are properly aligned. Refer to Figure 4.
3
Size Overlap
90
120
135
150
OVERLAP
165
RADIAL
180
GAP
202
225
245
270
300
330
DETAIL A
365
402
445
490
540
600
Figure 3
B51092-005
(inches)
5/32
3/16
3/16
7/32
7/32
7/32
1/4
9/32
5/16
5/16
3/8
13/32
7/16
1/2
17/32
19/32
21/32
3/4