Xylem 8200 Series Base Mounted Centrifugal Fire Pumps AC2675 REV.C - Manual (Page 20)

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length of time the pump has remained in the
flooded area, it is unlikely that bearing
replacement is necessary; however, in the event
that rust or worn surfaces appear, it may be
necessary to replace the bearings.
Next, inspect the stuffing box, and clean out any
foreign matter that might clog the box. Mechanical
seals should be cleaned and thoroughly flushed.
Couplings should be dismantled and thoroughly
cleaned.
Any pump that is properly sealed at all joints and
connected to both the suction and discharge
should exclude outside liquid. Therefore, it should
not be necessary to go beyond the bearings,
stuffing box, and coupling when servicing the
pump.
BEARING LUBRICATION – GREASE
Grease lubricated ball bearings are packed with
grease at the factory and ordinarily will require no
attention before starting, provided the pump has
been stored in a clean, dry place prior to its first
operation. The bearings should be watched the
first hour or so after the pump has been started to
see that they are operating properly.
The importance of proper lubrication cannot be
over emphasized. It is difficult to say how often a
bearing should be greased, since that depends on
the conditions of operation. It is well to add one
ounce of grease at regular intervals, but it is
equally important to avoid adding too much
grease. For average operating conditions, it is
recommended that 1 oz. of grease be added at
intervals of three to six months, and only clean
grease be used. It is always best if unit can be
stopped while grease is added to avoid
overloading.
NOTE: Excess grease is the most common cause
of over-heating.
A lithium based NLGI-2 grade grease should be
used for lubricating bearings where the ambient
temperature is above -20°F. Grease lubricated
bearings are packed at the factory with Shell
Alvania No 2. Other recommended greases are
Texaco Multifak No. 2 and Mobilux No. 2 grease.
Greases made from animal or vegetable oils are
not recommended due to the danger of
deterioration and forming of acid. Do not use
graphite. Use of an ISO VG 100 mineral base oil
with rust and oxidation inhibitors is recommended.
The maximum desirable operating temperature for
ball bearings is 180°F. Should the temperature of
the bearing frame rise above 180°F, the pump
should be shut down to determine the cause.
PACKING SEAL
When a pump with packing is first started it is
advisable to have the packing slightly loose
without causing an air leak. As the pump runs in,
gradually tighten the gland bolts evenly. The gland
should never be drawn to the point where packing
is compressed too tightly and no leakage occurs.
This will cause the packing to burn, score the shaft
sleeve and prevent liquid from circulating through
the stuffing box cooling the package.
NOTE: Eccentric run-out of the shaft or sleeve
through the packing could result in excessive
leakage that cannot be compensated for.
Correction of this defect requires shaft and/or
sleeve replacement. Packing should be checked
frequently and replaced as service indicates. Six
months might be a reasonable expected life,
depending on the operating conditions.
CLEANING WITHOUT DISMANTLING PUMP
A short section of pipe so designed that it can be
readily dropped out of the line can be installed
adjacent to the suction flange. With this
arrangement, any matter clogging the impeller is
accessible by removing the pipe section.
If the pump cannot be freed of clogging after the
above methods have been tried, dismantle the unit
as previously described to locate the trouble.