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Doc. ISM0076_MANUALE_CN SEAL-MV_ENG_REV04.DOCX
Foot valve undersized or partially
clogged
Check foot valve.
Excessive Suction lift
Check that NPSHa>NPSHr, suction line losses on
strainer and fittings
Suction pipe inlet not sufficiently
submerged
Consult system designer
Operating at very low flow
Check that flow is superior than minimum permitted.
Operating at high flow
Check that flow is superior than maximum permitted.
Unbalanced Impeller.
Consult
M PUMPS PROCESS.
Wear of the coupling motor-pump
Replace the coupling and proceed to the realignment of
pump and motor.
Suction pipe inlet not sufficiently
submerged
Consult system designer
Ball bearings or motor failure.
Check and replace them if necessary.
Uninsured motor or base plate.
Make sure that the motor and base plate are firmly
anchored to foundations and do not produce any
abnormal vibration.
Misalignment or improper anchoring of
the pipes.
Check correct alignment of pipes and supports, refer to
section 14.1 of this manual.
The pump was started while still rotating
in the opposite direction, for a previous
start.
Stop immediately the pump and drain all the liquid
from the discharge line before restarting.
OVERHEATING OF EXTERNAL BEARINGS (bare shaft versions)
Lack of oil or wrong type of oil in the
bearing frame.
Check the oil level: fill up or empty, and replace it if
necessary. Replace the bearings.
Excessive oil temperature into the bearing
frame.
Fill the bearing frame with oil as indicated in the
paragraph to restore the correct working temperatures.
MECHANICAL SEAL LEAKS EXCESSIVELY
Misalignment due to strain from pipes.
Check connections and eliminate any strains using
elastic coupling or other permitted method. Support
pipes.
Shaft bent.
Check shaft runouts are within acceptable values.
Bearing failure or worn.
Check bearings and replace it in case of failure or
worn.
Leakage under sleeve due to joint failure.
Check possible damages and replace joint.
Mechanical seal improperly installed.
Check alignment of faces or damaged parts and
investigate assembly method adopted.
Wrong mechanical seal type respect
operating condition.
Consult
M PUMPS PROCESS.
Unbalanced Impeller.