24
McQuay IM 672-7
Operation
Fan Startup
Start and run fan. Observe the rotation. If the fan operates
backward, reverse two legs of the three-phase supply power.
Note:
Variable pitch fan drives usually are provided for
operation in the mid-speed adjustment range. However,
the drives usually ship with the adjustment opened up for
minimum fan speed. Adjust the drives for the proper
airflow. See
Fan Drive Adjustments‚ page 30
.
After 48 Hours of Operation
1
Disconnect and lock electrical power source.
2
Check tightness of all bearing, wheel, and sheave setscrews
(or capscrews). Refer to
Table 7
.
3
Recheck belt tension and adjust if necessary. Belts
tensioned sufficiently to slip one to two seconds at startup
will perform satisfactorily, extending life and reducing
vibration. If retensioning is necessary, be certain to retain
sheave alignment.
Fan Wheel Alignment
Figure 34: Wheel-to-Inlet Funnel Relationship—Fan Wheels
(Housed)
Table 3: Wheel-to-Inlet Funnel Relationship—Fan Wheels
(Housed)
Note:
1
To obtain rated air performance, dimensional relationship must be held.
2
To obtain dimension A, loosen setscrews in wheel hub(s), shifting
wheel(s) axial as needed, retightening setscrews.
3
To obtain dimension B, loosen screw and washer fasteners around
periphery of funnel(s), shifting funnel radially as required, re-torquing
fasteners.
Figure 35: Wheel-to-Inlet Funnel Relationship—Forward
Curved Fan Wheels
Note:
1
To obtain rated air performance, dimensional relationship must be
held.
2
Adjust dimension C by loosening wheel hub setscrews, shifting
wheel(s) axial as needed, and retightening setscrews.
Figure 36: Wheel-to-Inlet Funnel Relationship—13 to 36
Plenum Fans
WARNING
ROTATING FAN
Can cause severe injury or death. Before servicing fans,
lockout and tag out power.
AVERTISSEMENT
VENTILATEUR EN ROTATION
Peut causer des blessures sévères ou même la mort. Avant
d’effectuer l’entretien des ventilateurs, bloquer et couper la tension.
Airfoil
1
Unit sizes 003 to 035
Unit sizes 040 to 090
Dia.
A
2
(in)
A
2
(mm)
B
3
(in)
B
3
(mm)
Dia.
A
2
(in)
A
2
(mm)
B
3
(in)
B
3
(mm)
13.22
4.56
116
0.21
5.33
20.00
7.19
183
0.31
7.87
14.56
5.06
129
0.21
5.33
22.25
7.69
195
0.33
8.38
16.18
5.62
143
0.21
5.33
24.50
8.56
217
0.31
7.87
17.69
6.90
175
0.22
5.59
27.00
9.47
241
0.63
16.00
21.56
7.59
193
0.24
6.10
30.00 10.47
266
0.39
9.91
24.00
8.45
215
0.23
5.84
33.00 11.75
298
0.38
9.65
36.50 12.78
325
0.38
9.65
40.25 14.31
363
0.50
12.70
A
A
B
E q u a l s p a c i n g
a l l a r o u n d
Table 4: Wheel-to-Inlet Funnel Relationship—Forward
Curved Fan Wheels
Forward curved
1
Unit sizes 003 to 035
Unit sizes 040 to 090
Diameter (in)
C
2
(in)
C
2
(mm)
Diameter (in)
C
2
(in)
C
2
(mm)
9 x 4
0.25
6.35
20 (Class 1 & 2)
0.24
6.10
9 x 7
0.13
3.30
22.38 (Class 1 & 2)
0.41
10.41
9 x 9
0.25
6.35
25 (Class 1 & 2)
0.47
11.94
10
0.22
5.59
27.62 (Class 1 & 2)
0.47
11.94
12
0.35
8.89
30 (Class 1 & 2)
0.47
11.94
15
0.44
11.18
33 (Class 1 & 2)
0.50
12.70
18
0.25
6.35
36 (Class 1 & 2)
0.75
19.05
20 (Class 1 & 2)
0.73
8.54
22 1/2 (Class 1 & 2)
0.59
14.99
24 1/2 (Class 1 & 2)
0.56
14.22
I n l e t
F u n n e l
W h e e l
C
C
I n l e t
F u n n e l
Cross Section Reference
C
AROUND DIAMETER
EQUALLY SPACED
B
A
FROM FUNNEL END TO
FANWHEEL OPENING END
