SPP Pumps Thrustream - Extended - Manual (Page 21)

Operators Instructions for Horizontal
Extended Thrustream Centrifugal Pumps
Manual No/Rev
W12-005E / 3
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.
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 plugged up or blocked.
Wrong direction of rotation.
Excessive wear ring clearance.
Damaged impeller.
Rotor binding.
Defects in motor.
Voltage and/or frequency lower than rating.
Foundation not rigid.
Misalignment of pump and driver.
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 lower the pump.
CAUSE REMEDIAL ACTION
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.
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 pump and clean the
impeller.
Wrong direction
of rotation. Check driver rotation with the direction
arrow on the pump casing.
Excessive wear
ring clearance. Replace the wear rings when the
clearance exceeds the maximum
tolerances.
Damaged
impeller. Replace if damaged or vanes are
eroded.
Rotor binding. Check for shaft run out, and replace 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.
Foundation not
rigid. Ensure that the foundation bolts are
tight; check that foundations match
SPP Pumps Ltd. Recommendations.
Misalignment of
pump and driver. Check shaft run-out and replace if
necessary.
Rotor out of
balance. Check impeller for damage, replace as
necessary.
Shaft bent. Check shaft run-out and replace if
needed.
Impeller too
small. Refer to SPP Pumps Ltd. for options to
fit a larger impeller.