Faults, Causes And Remedies - salmson NOLH Installation Et Mise En Service

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