KSB RDLO Series User Manual

RDLO
Page 22 of 24
8.2 Causes of Faults and Their Remedies
Faults
Pump discharge pressure too low
| Pump discharge pressure too high
| | Excessive flow rate
| | | Insufficient flow rate
||||Power consumption is too high
|||||Pump does not deliver after starting
||||||Pump interrupts delivering
|||||||Pump runs rough (noise, vibrations)
||||||||Impermissible temperature increase at pump casing / shaft seal housing
|||||||||Bearing temperature too high
||||||||||Excessive leakage at the shaft seal
|||||||||||Drive is overloaded
||||||||||||Leakage at the pump
|||||||||||||
|||||||||||||
Cause Remedy
xxxxxx xx x
Duty point B does not lie at the
calculated intersections of Q and H
- Re-adjust the duty point
x
Pump or piping are not completely
vented or primed
- Vent
x x xxxx
Supply lines or impeller clogged - Clean the impeller
- Check plant for impurities
- Remove deposits in pump and/or piping
- Check any strainers installed / suction opening
x x x Formation of air pockets in the piping - Correct the suction conditions
- Alter the piping
x x xxx
Suction head is too high
(NPSH
available
is too low) / liquid
level is too low
- Check mode of operation
- Correct the suction conditions
- Increase the suction head
- Increase the back pressure by throttling
- Install pump at a lower level
- Alter the suction / intake piping, if the resistances
are too high
xxxx
Air intake at shaft seal - Clean the sealing liquid line, possibly supply
sealing liquid from an external source and/or
increase its pressure
- Check the liquid level in feed tank
- Replace the shaft seal
- Replace the shaft protecting sleeve
xxxx x
Wrong direction of rotation - Interchange two of the phases of the power
supply
- Check the electrical connections
- Check the impeller position; correct, if required
xx x
Speed is too low - Increase the speed
1)
- Check the switchgear
- Fit a larger impeller
1)
xxxx
Wear of internal pump parts - Check duty point / pump design
- Increase back pressure by throttling
- Check medium handled for contamination by
chemicals and the solids content
- Replace worn components
x x Back pressure is lower than specified
in the order
- Re-adjust the duty point
- Increase the back pressure by throttling
xx
Density or viscosity of medium
handled is higher than stated in the
order
- Reduce the speed
- In case of permanent overloading, turn down the
impeller
1
)
xx x x x
Speed is too high - Reduce the speed
- In case of permanent overloading, turn down the
impeller
1
)
x
Tie bolts / seals and gaskets - Check
- Tighten the tie bolts
- Replace the seals and gaskets
- Check pipe connections and secure fixing of the
pump; if required, improve the fixing of the piping
x
Shaft seal is worn - Check flushing / sealing liquid pressure
- Clean the sealing liquid line, possibly supply
sealing liquid from an external source and/or
increase its pressure
- Replace the shaft seal
- Replace worn components
- Replace the shaft protecting sleeve
xx xx
Unfavourable flow to suction nozzle of
pump
- Alter the piping
- If required, alter the suction / inlet pipe, if the
resistances are too high
- Check the piping layout for swirl or irregular flow
profile (e.g. downstream of an elbow)
1) Consult KSB

KSB RDLO Series Specifications

General

Brand	KSB
Model	RDLO Series
Category	Water Pump
Language	English