salmson NOLH series, Installation And Operating Instructions Manual

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ENGLISH
22
10 FAULTS, CAUSES AND REMEDIES
Fault Cause Remedy
The pump is
not
producing
the rated
flow or head
‐ Discharge pressure is too high Open and clean discharge pipe
Check pump duty point
‐ Pump or piping is not completely vented or filled Vent pump casing
Fill completely suction pipe with liquid
‐ Suction lift is too high / NPSH available is too low Check liquid levels
Check that both suction and discharge isolating valves are open
Clean filters
‐ Impeller laminating ring is worn Replace impeller – Check wear in the casing
‐ Wrong direction of rotation Change two phases in motor junction box
‐ Leakage on pump casing gaskets, on shaft sealing or on suction piping Check the tightening of the casing cover fastening nuts
Replace casing seal
Replace mechanical seal
Check tightening of flanges fastening bolts
Check state of flanges gaskets
Pump does
not prime or
not
continuously
‐ Casing, shaft sealing, foot valve or suction piping leaks Replace casing seal
Check shaft sealing
Check tightening of flanges fastening bolts
Check aspect of flanges gaskets
‐ Suction lift is too high / NPSH available is too low If suction lift operation then check liquid levels
Check that isolating valve on suction line is opened
Clean filters if any
Check that available NPSH of the process is higher than the pump required NPSH
‐ Loose or jammed part in the pump Remove the back ‐ pull ‐ out assembly and clean the inside of pump
Pump leaks
‐ Casing seal leaks Check the tightening of the casing cover fastening nuts
Check the aspect of the casing seal
‐ Shaft sealing leaks (mechanical seal) Check the aspect of the mechanical seal faces and O’Ring
Proceed with replacement of the mechanical seal if required
‐ Shaft sealing leaks (stuffing box) If possible retighten the gland. If not possible replace packing rings / shaft sleeve
Temperature
of pump
increases
‐ Pump or piping is not completely filled with liquid Vent pump casing and suction line
Fill completely the suction pipe with liquid
‐ Suction lift is too high / NPSH available is too low If suction lift operation then check liquid levels
Check that isolating valve on suction line is opened
Clean filters if any
Check that available NPSH of the process is higher than the pump required NPSH
‐ Pump runs against closed valve Open isolating valve on discharge side
Temperature
of bearing
bracket
increases
‐ Oil lubricated ball bearings : oil level is too low in bearing bracket Add oil in bearing bracket
Check for a leakage
‐ Coupling not properly aligned Make proper coupling alignment
Pump runs
noisily
‐ Pump or motor ball bearing is worn Identify and replace worn ball bearing
‐ Pump or piping is not completely filled with liquid Vent pump casing and suction line
‐ Suction lift is too high / NPSH available is too low If suction lift operation then check liquid levels
Check that isolating valve on suction line is opened
Clean filters if any
Check that available NPSH of the process is higher than the pump required NPSH
‐ Pump is not properly leveled or base plate is distorted. Excessive forces applied on
flanges
Check pump installation
‐ Foreign material in the pump Remove back pull out assembly and clean the inside of pump casing
Motor
protection
switches off
‐ Current leakage Check earthing of motor
Find out the origin of current leakage : damaged cables, fluid leakage on electrical
components, …
‐ Stuffingbox over ‐ tightened Loosen packing gland and check packing lubrication
Replace packing rings
‐ Protection fuses not calibrated properly Check motor current and select motor protection accordingly
‐ Liquid density is higher than expected Calculate absorbed power and replace motor accordingly
‐ Pump runs right of curve or out of application limits Measure pump duty point and check pump runs in authorized application limits. If
necessary add a regulating valve or a calibrated orifice on pump discharge line
‐ Foreign matter remains inside the pump casing Remove back ‐ pull ‐ out assembly and clean the inside of pump casing