Sterling VS - Manual (Page 24)

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Open all disconnect switches and
secure in that position before servicing unit. Failure
to do so may result in personal injury or death from
electrical shock.
All rotating fans must stop before
servicing to avoid serious injury to fi ngers and
hands.
MOTOR LUBRICATION
Sleeve Bearings
Motors with oilers or oil holes are lubricated before
shipment with a good grade of electric motor oil. Refi ll
when necessary, with the motor at stand-still, until oil
reaches the proper level.
Use SAE 20W non-detergent oil for motors operating in
ambient temperatures of 32°F to 100°F (0°C to 38°C).
Above 100°F (38°C), use an SAE 30W to SAE 50W
non-detergent oil. Below 32°F (0°C), a SAE 10W non-
deterent oil will be required.
The frequency of oiling will depend upon operating
conditions and length of running time. Inspect the oilers
or oil holes when cleaning the unit. If the unit has a
fractional horse-power motor, lubricate at least once
a year. Under high ambient conditions or constant fan
operation, fractional horse-power motors should be
lubricated every 90 days. On those motors without oilers
or oil holes, follow the instructions given on the motor
nameplate.
Ball Bearings
Ball bearing motors are pre-lubricated and normally
not equipped with grease fi ttings. However, motors
are equipped with removable grease plugs to allow
installation of grease fi ttings if desired by the owner.
Motor manufacturers do not recommend or require on
the job lubrication of ball bearing motors. If on the job
lubrication is required by the owner, use the following
procedure: With the motor at a stand-still, remove the
vent and grease plugs. Install grease fi tting and add
grease sparingly. Remove the old grease from the
vent relief chamber. Operate the motor a few minutes
before reinstalling the vent plug to allow excess grease
to escape. If there is evidence of grease working out
around the motor shaft, less grease should be added and
the greasing periods lengthened. If grease continues to
appear, take the motor to the motor manufacturer’s
authorized service station for repair.
NOTICE: Consult local motor manufacturer’s service
facility for information on type of grease and oil to
be used.
MAINTENANCE
FAN AND MOTOR ASSEMBLY
For cleaning or maintenance purposes, the fan and
motor assembly may be removed easily from the Unit
Heater. The motor is attached to the fan guard which is,
in turn, mounted to the top or back panel of the unit as
shown in Figure 27.
On Vertical Units, reach up through the fan and remove
the fan guard mounting screws. Lower the motor, fan
and fan guard assembly down through the fan outlet.
If desired, the top and bottom panels may be removed
from the coil by taking out the four panel mounting bolts.
See Figure 27.
Figure 27 – Cross Section View
CLEANING THE UNIT
The unit casing, fan, diffuser and coil should be cleaned
thoroughly once a year. Coil heat transfer effi ciency
depends on cleanliness. The following recommended
procedures may be performed when lubricating the
motor and cleaning the coil.
1. Wipe all excess lubricant from the motor, fan and
casing. Clean the motor thoroughly. A dirty motor
will run hot and eventually cause internal damage.
2. Clean the coil:
a) Loosen the dirt with a brush on the fan side of
the coil. Operate the motor allowing the fan to
blow the loosened dirt through the unit.
b) Use air pressure or steam on the side of the coil
away from the fan.
NOTICE: A piece of cheesecloth or a burlap bag
may be used to collect the large particles during the
cleaning process.
3. Clean the casing, fan blades, fan guard and diffuser
using a damp cloth. Any rust spots on the casing
should be cleaned and repainted.
4. Tighten the fan guard, motor frame and fan bolts.
Check the fan for clearance in the panel orifi ce and
free rotation.
Fan Guard
Mounting Screws
Top
Panel
Panel Mounting
Bolts Bottom
Panel