Goulds Pumps 3408A - IOM - Manual (Page 33)

MAINTENANCE
GENERAL MAINTENANCE
Operating conditions vary so widely that to recommend one
schedule of preventative maintenance for all centrifugal
pumps is not possible. Yet some sort of regular inspection
must be planned and followed. We suggest a permanent
record be kept of the periodic inspections and maintenance
performed on your pump. This recognition of maintenance
procedure will keep your pump in good working condition,
and prevent costly breakdown.
One of the best rules to follow in the proper maintenance of
your centrifugal pump is to keep a record of actual
operating hours. Then, after a predetermined period of
operation has elapsed, the pump should be given a
thorough inspection. The length of this operating period
will vary with different applications, and can only be
determined from experience. New equipment, however,
should be examined after a relatively short period of
operation. The next inspection period can be lengthened
somewhat. This system can be followed until a maximum
period of operation is reached which should be considered
the operating schedule between inspections.
MAINTENANCE OF PUMP DUE TO
FLOOD DAMAGE
The servicing of centrifugal pumps after a flooded
condition is a comparatively simple matter under normal
conditions.
Bearings are a primary concern on pumping units. First,
dismantle the bearings; clean and inspect them for any
rusted or badly worn surfaces. If bearings are free from rust
and wear, reassemble and relubricate them with one of the
recommended pump lubricants. Depending on the 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 advised 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.
The grease relief plug should be removed from the
outboard bearing housing before adding new grease to the
bearing. The plug should then be left out until the pump is
run for a minimum of 2 hours and the system has reached
its normal operating temperature.
NOTE: Excess grease is the most common cause of
overheating.
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.
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.
MECHANICAL SEALS
1. Mechanical seals are precision products and should be
treated with care. Use special care when handling
seals. Clean parts are essential to prevent scratching
the finely lapped sealing faces. Even light scratches on
these faces could result in leaky seals.
2. Normally, mechanical seals require no adjustment or
maintenance, except routine replacement of worn or
broken parts.
3. A mechanical seal which has been used should not be
put back into service until the sealing faces have been
replaced or relapped. (Relapping is generally
economical only in seals two inches in size and
above.)
3408A IOM 6/08
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