AAON RL-240 - Manual (Page 43)

43
Step 7: Determine the current blade pitch and the pin location for the new blades
Table 9 - Return/Exhaust Fan Pin Location in the Bushing Mount
Type
Bushing
Mount
Blade Pitch Angle
20° 25° 28° 30° 33° 35° 38° 40° 45° 50°
5Z
A - RET - RET RET RET HUB HUB HUB HUB
B - HUB - HUB HUB HUB RET RET RET RET
Table 10 - Return/Exhaust Fan Pin Location in the Grooves
Type Rot.
Blade Pitch Angle
20° 25° 28° 30° 33° 35° 38° 40° 45° 50°
5Z
R - 4 - 3 2 1 4 3 2 1
L - 1 - 2 3 4 1 2 3 4
Step 8: Replace fan blades in the new pin
location and reassemble the fan
Replace the blades with the pin in the 1, 2,
3, or 4 groove position of either the HUB or
RET. Assemble the fan making sure to place
the blades in their previous blade sockets, to
match up the previous orientation of HUB
and RET and to replace any balancing
weights in their previous locations. Tighten
bolts in a cross pattern to 5-6 ft-lbs. of
torque.
RL Prop Assembly
The prop assembly bushings should be
tightened to the specifications listed in Table
11.
Table 11 - Prop Assembly Bushing Torque
Specifications
BUSHING
TIGHTENING TORQUE
(IN-LBS.)
H X 1.125" 95
H X 1.375" 95
SH X 1.125" 108
SH X 1.375" 108
SD X 1.125" 108
SD X 1.375" 108
SD X 1.625" 108
SD X 1.875" 108
SK X 2.125" 180
Spring Isolator Adjustment
NOTE: Resonance issues are possible when
both internal and external spring isolation
are used. When an external spring isolated
curb is used, internal fan spring isolators
should be locked down to prevent resonance
issues.
All spring isolators must be adjusted, prior
to unit startup, to avoid mechanical damage
or reduced performance.
1. On all four isolators, secure the
adjustment bolt and rotate the locking
bolt counter-clockwise approximately
four full rotations. This will allow the
locking bolt to spin when the adjustment
bolt is turned (See Figure 26).
2. Take two full counter-clockwise turns on
each adjustment bolt and continue to
evenly compress the springs until the
wooden shipping supports can be
removed and discarded.
3. Adjust all four isolators until 1¼”
clearance is obtained between all spring
brackets and spring supports. Rotating
the adjustment bolts counter-clockwise
will raise the blower frame and increase
the clearance.
4. Adjusting only the front isolators,
increase the clearance on the front
brackets by approximately ¼”. This will
result in a gap between the front of the
blower frame and the upper corners of