Sterling HS - Manual (Page 20)

20
MAINTENANCE
PERIODIC SERVICE
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.
Because of the simple design of the steam and hot
water unit heaters, they are nearly maintenance free.
However, depending on the environment, simple
maintenance practices should be adopted.
Periodically check the fi nned surfaces and vacuum
these as often as necessar y to remove any
accumulation of lint and dirt. Check fan blades and
remove dirt accumulation. If fan blades are not cleaned
they tend to become unbalanced.
Most of the motors supplied on the unit heaters have
either ball bearings or sleeve bearings and should not
require lubrication for long periods of time. It is however
advisable that motor maintenance and lubrication
recommended by the motor manufacturer be followed.
Check motors for dirt and dust accumulation, and
remove any accumulation as often as necessary. Open
type motors may overheat if the dirt or dust is not
removed from ventilation openings.
Allow rotating fans to 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 a 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). Below 32°F (0°C), SAE 10W non detergent 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 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.
NOTICE: The heater system should be checked once
a year by a qualifi ed technician. All maintenance/
service information should be recorded accordingly
on the inspection sheet provided in this manual.
Should maintenance be required, perform the following
inspection and service routine:
CLEANING THE UNIT
The unit casing, fan, diffuser and coil should be
cleaned thoroughly once a year. Coil heat transfer
efficiency 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 high pressure air 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.