Sterling SDFI, Installation And Maintenance Instructions Manual

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1. Blower Motors – Some motors require lubrication
while others do not. Those that require lubrication can
be identified by the presence of grease plugs in the
motor casing at each end. Motors that do not have
grease plugs cannot be greased and are lubricated for
the life of the motor bearing.
Lubrication of motors should be done while the motor
is warm and at a standstill. Remove and clean all
grease plugs and insert a grease fitting in the upper
hole in the motor casing at each end. (Viewed as if
motor were sitting horizontally on its base). There may
be one or two plugs in each end casing of the motor.
Add a small amount of a clean, good grade ball
bearing grease, such as Exxon Polyrex EM or equal,
with a low pressure grease gun. Run the motor five
minutes before removing the grease fittings and
replacing the plugs.
CAUTION: An excess of grease will overheat the
bearings.
NOTE: On totally enclosed fan cooled (TEFC)
motors, the rear end fan housing must be removed
to expose the grease plugs.
2. Pillow Block Bearings – Pillow block bearings are
used on supply blower(s). Bearings have been
prelubricated with a number 2 lithium base grease.
Relubrication should be done with a similar grease
using a low pressure grease gun. Wipe all grease
fittings clean before adding grease. Grease should be
added slowly, in small amounts at frequent intervals
while the shaft is being manually rotated.
A slight showing of grease at the seals with accompa-
nying normal bearing temperature indicates proper
lubrication. Normal temperature can range from “cool”
to “hot to the touch” depending on size, speed and
surrounding conditions. Excessive bearing tempera-
ture indicates faulty lubrication. An insufficient amount
of grease is suggested by a bearing showing no
grease at the seals, and a higher than normal tem-
perature and noise level. Excessive leakage of grease
at the seals, and a high operating temperature
suggest too much grease.
Frequency of Lubrication – Frequency of lubrication
depends upon operating conditions. The bearing
operating temperature is the best index for determining
a relubrication schedule. The following chart gives the
frequency of relubrication based upon continuous
operation for various operating temperatures and can
be used as a satisfactory guide for determining when
all ball and roller bearings should be relubricated.
Speed Temperature Cleanliness Interval
100 RPM Up to 125
°
F Clean 6 months
500 RPM Up to 150
°
F Clean 2 months
1000 RPM Up to 210
°
F Clean 2 weeks
1500 RPM Over 150
°
F Clean weekly
Any Speed Up to 150
°
F Dirty 1 week
to 1 month
Any Speed Over 150
°
F Dirty daily to
1 week
Any Speed Any Temp. Very Dirty daily to
1 week
Any Speed Any Temp. Extreme daily to
Conditions 1 week
3. Dampers – Dampers should be inspected monthly
for securely fastened linkages, and smooth operation.
If dampers are binding or excessively noisy, then
lubrication may be required. Place one drop of #20 wt.
machine oil on each blade bearing, and linkage ball
joint. Do not over lubricate, and wipe any excess from
the area. Be sure to note that dampers over 49 inches
long have intermediate bearings which require lubrica-
tion.
C. Air Filters
All filter banks should be equipped with a manometer
or differential pressure switch to indicate when the
filters are dirty. Filters should be replaced when the
differential pressure across them reaches the
manufacturer’s recommended final value. Dirty filter
elements should be replaced with a clean element of
the same type and size. In addition, Sterling not only
suggests, but insists, that air filters be checked every
30 days and replaced with new filters (throw-away
type) or cleaned (washable type) as required. Clean-
able filters should be given new application of filter
coating after washing to maintain optimum filter
performance.
The frequency of cleaning and replacing air filters
applies twelve months of the year, where blowers are
used for ventilation and heating.