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

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10 FAULTS, CAUSES AND REMEDIES

Faults
The pump is
not producing
the rated flow
or head
Pump does not
prime
continuously
Pump leaks
Temperature of
bearing bracket
increases
Pump runs
noisily
Motor
protection
switches off
Cause
- Discharge pressure is too high
- Suction lift too high or available NPSH too
low
- No water inlet or water inlet flow is to low
- Impeller laminating ring is worn
- Wrong direction of rotation
- Leakage on pump casing gaskets, on shaft
sealing
- Suction lift too high
- Air intake in suction line
- Loose or jammed part in the pump
- Casing seal leaks
- Shaft sealing leaks (mechanical seal)
- Missing grease in pump ball bearing
- Coupling not properly aligned
- Shaft sleeve or bushing is damaged
- Pump or motor ball bearing is worn
- Pump or piping is not completely filled with
liquid
- NPSH available is too low
- Pump is not properly leveled or base plate is
distorted. Excessive forces applied on flanges
- Foreign material in the pump
- Current leakage
- Protection fuses not calibrated properly
- Oil viscosity too high when cold
- Pump runs right of curve or out of
application limits
- Foreign matter remains inside the pump
casing
Remedy
Open and clean discharge line pipe work
Check pump duty point
Check liquid levels and head losses in suction pipe
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 liquid level in the tank at suction side
Check connections in suction line
Withdraw 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
Check proper venting of mechanical seal housing
Proceed with replacement of the mechanical seal
if required
Add grease in ball bearing
Make proper coupling alignment
Check correct venting of the loop
Replace the sleeve and the bushing
Identify and replace worn ball bearing
Vent pump casing and suction line
Check static pressure in the loop
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, ...
Check motor current and select motor protection
accordingly
Check oil viscosity at cold temperature and
calculate absorbed power during cold operation
Measure pump duty point and check pump runs in
authorized application limits
Remove back pull out assembly and clean the
inside of pump casing
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