116
IM 738-2
Maintenance:
Supply Fan Wheel-to-Funnel Alignment
Figure 114. Return fan assembly
Supply Fan Wheel-to-Funnel Alignment
If the unit is equipped with an airfoil or backward curved
supply fan, the fan wheel-to-funnel alignment must be as
shown in Figure 115, Figure 116, Figure 118 and Figure 119 to
obtain proper air delivery and operating clearance. If
necessary, adjustments are made as follows:
1
Verify that the fan shaft has not moved in its bearings.
2
Loosen the fan hub setscrews and move the wheel(s) along
the shaft as necessary to obtain the correct dimension
shown in Table 29, Table 30, and Table 31.
3
Retighten the setscrews to the torque specification given in
Table 28 on page 115. Tighten the setscrews over the
keyway first; tighten those at 90 degrees to the keyway last.
4
Verify that the radial clearance around the fan is uniform.
Radial clearance can be adjusted by slightly loosening the
funnel hold-down fasteners, shifting the funnel as required,
and retightening the fasteners.
Figure 115. 20" DWDI airfoil wheel-to-funnel (015C to 030C)
Figure 116. 24" DWDI backward curved wheel-to-funnel
(036C, 040C)
Figure 117. 27 to 40" DWDI airfoil wheel-to-funnel
alignment
Figure 118. 40" SWSI airfoil wheel-to-funnel alignment
(RDT 045 to 075)
U p p e r B e a r i n g
F a n W h e e l
F a n S h a f t
S u p p o r t
L o w e r
B e a r i n g
F a n S h a f t
F u n n e l
.
"
.
"
W h e e l
Table 29: 27 to 40" DWDI airfoil wheel-to-funnel
relationship
Wheel-to-funnel relationship (in inches)
Wheel diameter (inches)
A +0.3/ — 0.0
27
9.9 (246 mm)
30
10.6 (269 mm)
33
11.7 (297 mm)
36
13.1 (333 mm)
40
14.5 (368 mm0
Table 30: SWSI airfoil wheel-to-funnel relationship
Wheel-to-funnel relationship (in inches)
Wheel diameter
A
40
0.62
W h e e l
. 8 "
F u n n e l
9 .
"
9 .
"
C L
F a n
. 8 "
W h e e l
F u n n e l
A
Summary of Contents for RDT-135c
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