Fan Shaft Bearing Removal
1. Lock open and tag electrical disconnect.
2. Enter through fan section access door or remove panels
as required.
3. Place plywood or other rigid covering on floor to pro-
tect insulation from damage.
4. Loosen motor base to frame bolts. Adjust motor to re-
lease belt tension and remove belts. Do not stretch belts
over sheaves. Damage to belts can result.
5. Remove bolts on bushing of fan shaft sheave, insert bolts
in jacking hole provided on bushing and slowly jack bush-
ing from sheave. Remove bushing and sheave.
6. Loosen bearing holddown bolts, block shaft up.
7. Loosen bearing setscrews and locking collar, and re-
move holddown bolts.
NOTE: To facilitate easy removal of setscrew fastened
wheels, sheaves, or bearings, remove the setscrew com-
pletely. Taking care not to damage threads, insert a flat
ended drift or punch, tap lightly and carefully return the
material displaced on the shaft by the setscrew to its origi-
nal place.
8. Remove bearing while observing the following
precautions:
a. Make certain fan shaft surface is not rough or scored.
If so, clean up surface with fine emery cloth.
b. Add a few drops of oil after cleanup of shaft end.
It should not be necessary to drive a new bearing
onto shaft. If light tapping is needed, do not tap
against outer race.
9. Check fan shaft diameter at bearing mount. If worn by
more than 0.001 in. below nominal, shaft should be
replaced.
10. Install new bearing, tighten holddown bolts, and then
tighten bearing locking collar or setscrews.
11. Make certain fan wheel does not rub sides of fan hous-
ing after installing new bearings.
12. Recoat fan shaft with a rust inhibitor or grease.
13. Replace sheave and belts. Adjust and align as described
in Installation, Sheaves and V-Belts, pages 38 and 39.
14. Remove insulation protection.
15. Replace access panels.
16. Restore electrical power.
Fan and Shaft Removal — On airfoil and forward-
curved fans, the fan wheel and shaft may be removed through
inlet side of fan housing. See Fig. 72. On plenum fans,
remove side, top, or end panel opposite inlet, wherever duct-
work is not connected. After removing panel, proceed as
follows.
1. Remove drive belts as described in Fan Shaft Bearing
Removal section above.
2. Block up fan wheel within housing to prevent dropping
when bearing bolts are removed.
3. Loosen bearing holddown bolts, block shaft up.
4. Loosen bearing setscrews and locking collar, and re-
move holddown bolts.
NOTE: To facilitate easy removal of setscrew fastened
wheels, sheaves or bearings, remove the setscrew com-
pletely. Taking care not to damage threads, insert a flat
ended drift or punch, tap lightly and carefully return the
material displaced on the shaft by the setscrew to its origi-
nal place.
5. Remove bearing support channels and inlet ring from
one side.
6. Remove fan shaft and fan wheel from unit.
7. Remove fan shaft from fan wheel.
8. Replace shaft and wheel into fan in the reverse order of
their removal.
9. Inspect bearings and if serviceable, replace on shaft.
10. For airfoil and forward-curved fans, align fan wheel and
shaft assembly in fan scroll. Check cutoff location if wheel
failure damaged cutoff plate. See Fig. 73. For plenum
fan, align wheel and shaft assembly per manufacturer’s
directions supplied with fan.
11. Tighten bearing holddown bolts, bearing setscrews, and
shaft setscrews.
12. Field balancing of shaft and wheel is recommended.
IMPORTANT: Replacement shafts must have a
+.0000
diameter tolerance at bearing mount of in.
-.001
nominal. Carrier specified parts are recommended.
Fig. 72 — Fan Shaft and Bearing Removal
89
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