SPP Pumps Thrustream - Manual (Page 19)

Operators Instructions for Horizontal
Standard Thrustream Centrifugal Pumps
Manual No/Rev
W12-003E / 6
Our policy is one of continuous improvement and we reserve the right to alter specifications at any time
Page 19 of 28
7. Faults and Remedial Action
POTENTIAL FAULT OR DEFECT:
No liquid delivered.
Insufficient liquid delivered.
Liquid delivered at low pressure.
Loss of liquid after starting.
Excessive vibration.
Motor runs hotter than normal.
Excessive noise from pump cavitation.
Pump bearings run hotter than
normal.
PROBABLE CAUSES
Pump not primed.
Speed too low.
Speed too high.
Air leak in suction pipework.
Air leak in mechanical seal.
Air or gas in liquid.
Discharge head too high (above
rating).
Suction lift too high.
Not enough head for hot liquid.
Inlet pipe not submerged enough.
Viscosity of liquid greater than
rating
Liquid density higher than rating.
Insufficient nett inlet head.
Impeller blocked.
Wrong direction of rotation.
Excessive impeller clearance.
Damaged impeller.
Rotor binding.
Defects in motor.
Voltage and/or frequency lower
than rating.
Lubricating grease or dirty oil or
contaminated.
Foundation not rigid.
Misalignment of pump and driver.
Bearing worn
Rotor out of balance.
Shaft bent.
Impeller too small.
CAUSE REMEDIAL ACTION
Pump not primed. Fill pump and suction pipe completely with
fluid.
Speed too low. Check that the motor is correctly connected
and receiving the full supply voltage also
confirm that the supply frequency is correct.
Speed too high. Check the motor voltage.
Air leak in suction
pipework. Check each flange for suction draught, rectify
as necessary.
Air leak in
mechanical seal. Check all joints, plugs and flushing lines, if
fitted. Note that prolonged running with air in
the mechanical seal will result in damage and
failure of the seal.
Air or gas in
liquid. It may be possible to increase the pump
performance to provide adequate pumping.
Discharge head
too high (above
rating). Check that valves are fully open and for pipe
friction losses. An increase in pipe diameter
may reduce the discharge pressure.
Suction lift too
high. Check for obstruction of pump inlet and for
inlet pipe friction losses. Measure the static
lift, if above rating, raise the liquid level or
CAUSE REMEDIAL ACTION
lower the pump.
Not enough head
for hot liquid. Reduce the positive suction head by raising
the liquid level.
Inlet pipe not
submerged
enough. If the pump inlet cannot be lowered, provide a
baffle to smother the inlet vortex and prevent
air entering with the liquid.
Viscosity of liquid
greater than
rating. Refer to SPP Pumps Ltd for guidance to
increase the size or power of the motor or
engine.
Liquid density
higher than
rating. Refer to SPP Pumps Ltd for guidance to
increase the size or power of the motor or
engine.
Insufficient nett
inlet head. Increase the positive suction head by lowering
the pump or raising the liquid level.
Impeller blocked. Dismantle the pump and clean the impeller
Wrong direction
of rotation. Check driver rotation with the direction arrow
on the pump casing.
Excessive
impeller
clearance. Replace the impeller when clearance exceeds
the maximum adjustment.
Rotor binding. Check for shaft deflection, check and replace
bearings if necessary.
Defects in motor. Ensure that motor is adequately ventilated.
Refer to manufacturers' instructions.
Voltage and/or
frequency lower
than rating. If voltage and frequency are lower than the
motor rating, arrange for provision of correct
supply.
Lubricating
grease or oil dirty
or contaminated. Dismantle the pump, clean the bearings,
reassemble the pump and fill with new grease
or oil
Foundation not
rigid. Ensure that the foundation bolts are tight,
Check that foundations match SPP Pumps Ltd
recommendations
Misalignment of
pump and driver. Realign the pump and driver as specified.
Bearings worn. Remove the bearings, clean and inspect for
damage and wear, replace as necessary.
Rotor out of
balance. Check impeller for damage, replace as
necessary.
Shaft bent. Check shaft run-out and replace if necessary.
Impeller too
small. Refer to SPP Pumps Ltd for options to fit a
larger impeller.