10
Twin City IM-4800
Maintenance
Installation and maintenance are to be performed only by
qualified personnel who are familiar with local codes and
regulations and experienced with this type of equipment.
Preventive maintenance is the best way to avoid
unnecessary expense and inconvenience. Start-up and
routine maintenance should cover the following items:
a. Tighten all setscrews, bolts and wire connections.
b. Check belt tension and sheaves for wear.
c. Lubricate fan bearings (see Tables 3 and 4).
d. Cleaning of unit, propeller and damper (if present).
All motors containing ball bearings are permanently
lubricated from the factory. No additional maintenance
is required.
1. Before performing any maintenance on the fan, be
sure power is turned off and locked in the OFF
position at the service entrance.
2. Ventilators should be carefully checked at least once
a year. For critical or rugged applications, a routine
check every two or three months is suggested.
3. All motors supplied with Twin City Fan & Blower
ventilators carry a one-year limited warranty from
date of shipment. For repairs within the warranty
period, the motor must be taken to the motor
manufacturer’s authorized service dealer. Contact
your representative for additional warranty details.
4. A periodic motor check should consist of spinning
the motor shaft with the power off to be sure the
motor turns freely and the bearings run smoothly.
The belt on belt driven units should be removed
from the motor sheave.
5. When removing or installing a belt, do not force the
belt over the sheave. Loosen the motor mount so
that the belt can be easily slipped over the sheave.
6. The belt on belt driven units should be removed and
carefully checked for glazing, cracks, ply separation
or irregular wear. A small irregularity in the contact
surface of the belt will result in noisy operation. If
any of these defects are apparent, the belt should
be replaced. Check the sheaves also for chipping,
dents or rough surfaces which could damage the
belt.
7. The correct belt tension is important. Too tight of
a belt will result in excess bearing pressure on the
motor bearings and shaft pillow blocks and may also
overload the motor. Too loose of a belt will result in
slippage which will quickly “burn” out belts. A belt
should feel “live” when thumped, approximately
1
⁄
4
"
belt deflection (3 to 5 lb.) when subject to finger
pressure at midpoint between sheaves.
8. The belt alignment should also be checked to
be sure the belt is running perpendicularly to the
rotating shafts. Fan and motor shafts must be
parallel. Improper alignment will result in excessive
belt wear.
9. Check sheave setscrews to ensure tightness. Proper
keys must be in keyways.
10. For blade angle adjustments on Type 'E' Propellers
(Level 3) refer to Engineering Supplement ES-404.
11. If unit is to be left idle for an extended period, it
is recommended that belts be removed and stored
in a cool, dry place to avoid premature belt failure.
12. The standard pillow block bearings on belt driven
ventilators are factory lubricated and are provided
with external grease fittings. Annual lubrication is
recommended, or more frequently if needed (see Table 3).
It is recommended to add fresh grease at start-up,
but do not over-grease. Use only 1 or 2 shots of
a recommended lubricant with a hand gun in most
cases (see Table 4). Maximum hand gun rating 40
P.S.I. Rotate bearings during lubrication where good
safety practice permits.
The most frequent causes of bearing failure are not
greasing often enough, using an excessive quantity
of grease or using incompatible greases. Excessive
vibration, especially if the bearing is not rotating, will
also cause bearings to fail. Bearings must also be
protected from water and moisture to avoid internal
corrosion.
13. During the first few months of operation it is
recommended that the bearing setscrews be
checked periodically to ensure that they are tight.
14. The rotating propeller requires particular attention
since materials in the air being handled can build
up on the blades to cause destructive vibration or
weaken the structure of the propeller by corroding
and/or eroding the blade metal. Regular inspection
and corrective action at intervals determined by the
severity of each application are essential to good
service life and safety.
Sharp edges and screws are a potential injury
hazard. Avoid them.
CAUTION
Hazardous moving parts. Unit may contain protected
fan motor which may start automatically and cause
injury. Allow time for reset.
Disconnect power before
servicing.
WARNING
Greases of different soap bases (lithium,
sodium, etc.) may not be compatible when
mixed. Prevent such intermixing by completely
purging the bearing of old greases.
CAUTION
