Fume Exhaust Fans
16
For Arrangement 10 Only
The intent of this procedure is to allow a field service
technician to replace bearings with the fan remaining
in place in its intended application. All work can
be conducted by accessing the bearings by either
removing a shaft guard, a weatherhood or working
under a weatherhood. This is dependent on the size of
the unit. This procedure assumes the power source has
been locked out prior to removing guards and covers,
belts and pulleys have been loosened and removed
properly and extended lubrication lines have been
disconnected at the bearing. In some cases, it may
be necessary to remove the fan inlet cone and wheel
if the bearings cannot be removed due to corrosion or
damage. See Radial Gap, Overlap and Wheel Alignment
on page 10 to the realign wheel upon installation.
Bearing Removal
This procedure assumes proper safety measures have
been taken.
• Read and follow all instructions carefully.
• Disconnect and lock-out power before installation
and maintenance.
• Driven sheaves and belts have already been
removed.
• Shaft black coating can be removed with a solvent
similar to a brake/carburetor cleaner.
1. Scribe a line around the shaft by both bearings and
around the bearing base to the bearing support or
write down the measurement from the end of the
shaft to the bearings. This will help in repositioning
the new bearing and wheel cone overlap.
2. Follow the bearing manufacturers’ procedures for
removal and installation.
3. Before removing the bearing bolts, make sure the
shaft is supported slightly. Remember to consider
the wheel weight on the shaft.
4. Remove both bearings from the shaft and clean/
remove any burrs using an emery cloth or file.
5. Clean mounting surface of any dirt or grease.
Bearing Installation
1. Before installing, read bearing manufacturers’
procedures. Before putting the new bearings on
the shaft, you may need to break what is called
swivel torque on the bearings (depending on style
of bearing). This is done by holding the bearing
housing securely and being able to move the inner
bearing race around freely.
2. Apply light film of oil on shaft, then gently slide the
new bearings onto the shaft.
Do not hammer bearing onto shaft!
3. Align bearings on shaft with the previous scribe
marks that are on the shaft and lock bearing to
shaft.
4. Put bolts into mounting surface and bearings. Do
not tighten.
5. Remove blocks if shaft is supported.
6. Set bearings on support with the scribed marks
locating the bearings. Make sure bearings are
square and level with the shaft.
7. Tighten bolts and torque bearing bolts, bearing
set screws/locking collars as per bearing
manufacturers’ procedures.
8. Rotate shaft by hand to help allow the bearings to
help set in. Also at this time, listen for any unusual
noises such as wheel rubbing on cone and any
bearing noise.
9. Connect extended lube lines in new bearings if
needed.
10. Reinstall the drive sheaves and belts. Check the
belt alignment.
11. Make sure to reinstall all guards and follow proper
safety measures before starting up the fan.
Bearing Replacement
