Power Return And Exhaust Axial Flow Fans (26 And 31-140 Tons); Table 13 - Pin Location; Table 14 - Pin Groove Location; Figure 36 - Assembled Fan - AAON RN Series Installation Operation & Maintenance

Step 7: Determine the current blade pitch and the pin location for the new blades
Bushing
Type
Mount 20°
A
5Z
B
Type Rot.
20°
R -
5Z
L -
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.
Power Return and Exhaust Axial Flow
Fans (26 and 31-140 tons)
Blade Pitch Angle Setting Instructions
Step 1: Determine the new required pitch for
the fan blades
Use the fan program in AAON ECat. Contact
the AAON parts department to acquire the
new pitch pins for the fan blades.
Step 2: Maintain the balance of fan
Mark the hub plate castings across a single
joint, so the fan can be reassembled in the
same orientation.
Mark the location of any balancing weight.
Balancing weight will be on the outer bolt
circle, in the form of washers, and/or longer
bolts, or an additional balancing nut.
54

Table 13 - Pin Location

25° 28°
- RET -
- HUB - HUB

Table 14 - Pin Groove Location

25° 28°
4 -
1 -
Blade Pitch Angle
30° 33° 35°
RET RET RET
HUB HUB
Blade Pitch Angle
30° 33° 35°
3 2 1
2 3 4
Number the blades and blade sockets, so that
they can be replaced into their origina l
positions.
Hub

Figure 36 - Assembled Fan

Step 3: Remove the mounting nuts and bolts
and separate hub plate castings

Figure 37 - Back of the Fan

38° 40° 45°
HUB HUB HUB
RET RET RET
38° 40° 45°
4 3 2
1 2 3
Bushing
Mount
Fan
Blade
50°
HUB
RET
50°
1
4