3. Break bond between the rotor and bushing by screwing bolts into
tapped holes in hub. Tighten bolts slowly and equally to avoid
cocking hub on bushing.
4. Remove hub and blade assembly.
5. If blades are to be removed from hub, matchmark each blade so it
can be replaced in the same blade socket and follow steps 5a, 5b,
5c and 5d.
5a. Loosen set screw located in blade skirt adjacent to leading
edge of blade.
5b. Remove locking ring from the blade retainer halves with the
use of external snap-ring pliers (Waldes #0609)
5c. Remove blade retainer halves.
5d. Slide blade from blade socket.
6. If QD bushing is to be removed, locate and mark its location
relative to end of shaft to facilitate reassembly, and follow steps
6a, 6b and 6c.
6a. Loosen the two set screws in the QD bushing.
6b. Remove the socket head cap screw (clamp screw).
6c. Slide bushing from shaft.
D-1-b Wheel Reassembly
If QD bushing has not been removed from the motor shaft, start with
1. Place QD bushing on motor shaft.
1a. Replace and tighten clamp screw to secure QD bushing to
1b. Tighten the two set screws in the bushing.
2. If blades have been removed from the hub, replace in their
previously marked sockets.
2a. Replace blade retainer halves.
2b. Lock blade retainer halves in place with locking ring.
2c. Reset blade pitch angle in accordance with data on fan
nameplate and secure by tightening set screw in blade
Do not lubricate the bushing, bore or bolts. Lubricants
on these surfaces may result in hub stresses high enough to
fracture the mounted hubs.
Place rotor assembly on QD bushing and secure assembly to
bushing with hex head bolts. Tighten bolts slowly and equally to
avoid cocking hub on bushing.Torque bolts to the following values:
A Hub – 10 ft. lbs.
B Hub – 40 ft. lbs.
C Hub – 90 ft. lbs.
4. Replace nose piece.
5. Follow start-up check list (Section B-11)
D-1-c Motor Removal
In order to remove the motor from the VAV fan, A/4, it is necessary to
to have access to both the inlet and discharge of the unit.
1. Remove hub and blade assembly per instructions in Section D-1-a.
2. Remove conduit box cover and disconnect all wiring.
3. Remove remainder of conduit box from fan casing.
4. Disconnect conduit pipe between fan casing and motor and remove.
Be careful in removing conduit that motor leads are not damaged.
5. Disconnect and remove external lubrication lines.
6. Some large horsepower motors have “stay bolts” between the fan
casing and motor at the “opposite shaft” end of the motor. Remove
7. Block motor securely so it is not damaged when motor mounting
bolts are removed.
8. Remove motor mounting bolts. Bolts are removed from inlet side
of fan. Bolts extend through the motor mounting plate into the
C-face of the motor.
9. Remove motor from fan casing through discharge end of fan.
D-1-d Installing Motor
1. Place motor into fan casing through the discharge end of the fan.
The C-face of the motor fits into the machined recess in the motor
2. Secure motor to mounting plate with motor mounting bolts. Bolts
are replaced from the inlet side of the fan. Bolts extend through
the motor mounting plate into the C-face of the motor. If original
bolts are not used, insure that the replacement bolts are minimum
Grade 5 quality.
3. Replace “stay bolts” if required.
4. Replace and connect external lubrication lines.
5. Thread motor leads through conduit pipe and replace and connect
conduit pipe to motor and fan casing.
6. Replace conduit box and reconnect all wiring.
7. Replace conduit box cover.
8. Replace wheel assembly per Section D-1-b.
9. Follow start-up check list (Section B-11).
Adjustable Pitch – Arrangement 8
Warning: Disconnect all power sources from fan to avoid electrical
shock and personal injury from rotating parts.
D-2-a Wheel Removal
See Section D-1-a
D-2-b Wheel Reassembly
See Section D-1-b
D-2-c Bearing Removal
1. Drive end bearing can be replaced without removing wheel from
shaft if care is taken in removing it. Replacement of wheel end
bearing requires wheel to be removed per Section D-1-a.
2. Remove inner fairing cover from drive end of fan and disconnect
and remove V-belt.
3. Remove fan sheave from shaft.
Note: Depending on fan size and horsepower, some Arrangement
9 fans have flange mounted bearings and others have pillow block
bearings. Instruction are similar for both types. When pillow block
bearings are removed, mark and save any shims so they can be
replaced in the same position.
4. If drive-end bearing only is to be removed, follow instructions in
4a, 4b and 4c.
4a. Block shaft securely to prevent damage to wheel and bearing
when drive-end bearing is removed.
4b. Loosen Allen-head bolts in bearing locking collar.
4c. Remove bearing mounting bolts and carefully slide bearing
5. If both bearings are to be removed, follow instructions in 5a, 5b,
5c and 5d.
5a. Remove wheel assembly per Section D-1-a.
5b. Loosen Allen-head set screws in bearing locking collars.
5c. Slide shaft from bearings.
5d. Remove bearing mounting bolts and remove bearings.
D-2-d Bearing Replacement
1. Replace bearings and snug up bearing mounting bolts. Do not
tighten securely. If pillow block bearings are used, replace any
shims in their proper location.
2. Slide shaft into bearings, position for axial location and tighten
set screws in locking collar.
3. VAV fans have a close tip clearance between the blade tips and
housing, so centering of shaft in the housing is critical. Attach
‘sweep arm” to shaft in rotor tracking area and adust bearing
position to assure uniform tip clearance around the housing.
4. Secure bearing mounting bolts.
5. Check axial location of shaft and adjust as necessary.
6. Replace wheel assembly per instructions in Section D-1-b.
7. Replace and align fan sheave and V-belt drive.
8. Replace inner fairing cover.
9. Follow start-up check list (Section B-11).
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