Operation And Maintenance - EBARA 4WN Manual De Instrucciones

the pump should be shut down and the bore should be at-
tended to before restarting the pump.
4WN submersibles pumps are not guaranteed against failu-
re due to pumping sand. Pumping of sand, even small quan-
tities of very fine sand will shorten the effective life of any
pump.
The pump should be run for a period of at least 30 minutes
and then the water level in the bore checked to ensure that
the water level in the bore has not dropped to a dangerously
low level. Continuous monitoring of bore water level is re-
commended.
Continuing operation at low water level will cause damage to
the pump and motor mechanical parts due to alternating
shock pressures on the pump.

11. OPERATION AND MAINTENANCE

The pump must not be operated with the delivery valve
shut off (closed head) for more than a few seconds
otherwise the motor will overheat, possibly causing
permanent damage, not covered by guarantee.
While 4WN submersible pumps do not require regular main-
tenance, it is a good practice to monitor the conditions and
performance of the pump and motor. This diagnosis may be
carried out by checking the maximum pressure (shut valve
for a very short period) generated by the pump, and by che-
cking the amperage draw of the motor at standard duty
flowrate.
Both these figures should be compared to pressures and
current draws recorded when the unit was initially installed.
Any reduction in pressure may indicate wear in the pump,
while any increase in motor current indicates a possible
overload condition. Consult the pump service chart for
further diagnosis of possible causes
PUMP SERVICE CHART
11.1
The following chart offers a means of diagnosing general
pump problems:
PROBLEM
− Control box or thermals in the sun or
near heat source.
OVERLOAD
− lncorrect thermals or control box fotted.
PROTECTOR
− Low line voltage.
TRIPS
− Phase failure (3 phase only).
− Faulty motor
− Water level in bore too low.
− Check valve installed backwards or
stuck closed.
NO WATER
− lnlet screen on pump clogged.
DELIVERED
− Hole in delivery piping below bore top.
− Molor failure.
− Broken pump shaft or coupling.
− Pump rotating backwards (3 phase
only).
− Water level too low in bore.
− Discharge piping clogged, corroded or
ruptured.
LOW WATER
− Pump inslalled too low in bore and
DELIVERED
covered in sand or other solids.
− lnlet screen partially clogged.
− Wom pump.
− Check valve stuck partially closed.
− Motor related problem.
− Water logged pressure tank.
− Pressure switch differential adjustment
PUMP STARTS
incorrect.
AND STOPS TOO
− Pressure tank too small.
OFTEN
− Other control problems (eg. probes too
close).
− Fuses too small.
− Fuse receptacles dirty or corroded.
FUSES BLOW BUT − Loose connection in fuse box.
OVERLOAD DOES − Defective incoming power leads.
NOT TRIP − Ground wire connected to wrong
terminal.
− Molor failure.
ELECTRIC − lncorrectly wired incoming power leads.
SHOCK FROM − Ground wire connected to motor control
WATER PIPE equipment.
OR ELECTRICAL − Defective motor starter or control box.
COMPONENTS − lncorrectly grounded motor.
PRESSURE − Water level too low in bore.
GAUGE
FLUCTUATES
WILH FLOW
SURGES
− Pump earthing to ground through poor
PUMP AND/OR
splice connection or cable chaffing.
MOTOR
− Unsatisfactory pH levels.
CORROSION DUE
− Active single w re earth return electrical
TO ELECTROLYSIS
distribulion system.
POSSIBLE CAUSES
EN
11