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254
Fig. 210 —
HEPA Filter Arrangement (cont)
Fan and Shaft Removal
On airfoil fans, the fan wheel and shaft may be removed
through inlet side of fan housing. See Fig. 211. On plenum
fans, remove side, top, or end panel opposite inlet, wherever
ductwork is not connected. After removing panel, proceed as
follows.
1. Remove drive belts as described in Fan Shaft Bearing Re
-
moval section (page 217).
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 remove
holddown bolts. On forward-curved fans, remove cut-off
plate. Remove fan wheel through discharge opening.
NOTE: To facilitate easy removal of setscrew fastened wheels,
sheaves or bearings, remove the setscrew completely. 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 original 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. 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.
12"
24"
24"
24"
UNIT SIZE: 58T
(12) 24" X 24" FILTERS
(4) 12" X 24" FILTERS
24"
8601
8607
8607
8607
24"
8601
8607
8607
8607
24"
8601
8607
8607
8607
24"
8601
8607
8607
8607
Important: Replacement shafts must have a diameter
tolerance at bearing mount of +.0000 in./-.001 in. nom
-
inal. Carrier specified parts are recommended.
Fig. 211 —
Fan Shaft and Bearing Removal