Frequency. As with the centrifugal pumps, the frequency of
complete overhaul depends on the hours of operation, severity of operation, etc.
Generally, however, a pump in continuous operation should be pulled for inspection
and overhaul annually. Perform the overhaul under experienced supervision and in
strict accordance with the manufacturer's manual. Overhaul the pump if any of the
following conditions exist, regardless of scheduled frequency of maintenance:
The pump shaft does not turn freely because parts
below the pump head are binding.
The pump shows excessive vibration.
A performance test shows a decrease of 25 percent
in capacity under normal head and speed conditions.
Clearances. When a pump is pulled, check the diametrical
clearance of each bearing ring to make sure it is between 0.025 and 0.050 inch (0.64
and 1.25 mm). Allow a maximum diametrical clearance of 0.025 inch (0.64 mm) on oil-
lubricated bearings. Maximum allowable clearances for water-lubricated cutless rubber
0.070 inch (1.8 mm) for shaft diameters 1.5 to 4 inches (40 to 100 mm).
Dismantling and Reassembly. Follow the same procedures
listed for centrifugal-type pumps.
Alignment. Check the pump and motor alignment each year.
Painting. Annually, or when the pump is pulled, paint all
iron parts with a good grade of underwater paint or effective protective coating on the
exterior of the pump and, if possible, on the interior parts subject to rust. Apply the
paint only to surfaces that are clean and dry. Do not paint the data plate.
Reciprocating Well Pumps
General Information. Use the manufacturer's manual to develop
checklists for each reciprocating well pump.
Delivery. Measure the pump output twice a year for a known
number of strokes. Delivery per stroke should be at least 90 percent of the volumetric
displacement of the pump (plunger area times stroke length). When the pump delivery
drops to 50 percent or less, or when the pump delivery is between 50 and 90 percent
but less than the installed water requirements, remove the pump from the well and