centrifugal pump continuously with a closed discharge, or overheating and
seizing may result. Operate pumps at least once a week; do not have a unit
s t a n d i n g idle for prolonged periods. Check stuffing box conditions; always
p e r m i t sufficient water leakage for cooling and lubrication. After the
packing has been in service for some time, it may require tightening to
prevent excessive water leakage. T i g h t e n gland nuts evenly to prevent tilting
a gland, which could score the shaft or shaft sleeve.
5 . 2 Preventive Maintenance Inspection.
I n s p e c t for the following conditions.
(1) Check for abnormal water pressure, temperature, and flow
( 2 ) Check for abnormal vibration, noise, and overheating.
( 3 ) Check for too much or too little packing leakage.
( 4 ) Check for hot stuffing box.
( 5 ) Check for hot bearings.
I n s p e c t for the following conditions:
( b ) Semiannually.
(1) Check alignment of pump and drive at normal operating temperature.
( 2 ) Check shaft or shaft sleeve for scoring.
( 3 ) Repl ace packing when excessive tightening of the gland is
required to keep l e a k a g e within limits. O c c a s i o n a l l y , packing replacement is
necessary if the packing becomes hard and tends to score the shaft.
( 4 ) D r a in oil from oil lubricated bearings; clean, flush, and refill
with new oil.
( 5 ) Check lubrication of grease-lubricated bearings. Do not over
grease. S a p o n i f i c a t i o n of the grease may occur if water infiltrates past the
b e a r i n g shaft seals. T h i s condition may be readily noticed as it gives the
grease a w h i t i s h color. R e p l a c e grease if saponified.
( c ) Y e a r l y . Dismantle the pump for a complete inspection and overhaul
u s i n g the following procedure.
I n s p e c t for wear, corrosion, and erosion. Remove
( 1 ) Remove rotor.
any deposit or scaling.
(2) Check wearing clearances according to manufacturer's
i n s t r u c t i o n . Generally, wearing ring clearances should not exceed 0.003 inch
per inch on the diameter of the wearing rings.
(3) Clean the water seal piping and inspect and clean the seal
Inspect and clean stuffing boxes and replace packing.