En
gl
is
h (
G
B)
26
A:
The pump delivers no liquid.
B:
The pump does not deliver enough liquid.
C:
The pump does not create enough pressure.
D:
The pump loses liquid after running for a short time.
E:
The pump consumes too much power.
F:
The motor is overloaded.
G:
Vibrations.
H:
Cavitation noise.
I:
The pump bearings are overheated.
J:
The pump operates for a short time and then stops.
K: Reference numbers to remedies.
A
B
C
D
E
F
G
H
I
J
K
●
Obstruction in the casing.
17
●
●
●
●
Air or gases in the liquid.
18
●
●
The actual duty point of the pump lies to
the right of the specified duty point on
the pump curve. The result is lower
head, higher flow and higher power
consumption.
19
●
●
The viscosity or specific gravity of the
pumped liquid is higher than that of
water.
20
●
●
●
●
The shaft is bent due to damage.
21
●
●
●
●
Mechanical failure of the bearing and/or
impeller.
22
●
●
●
Misalignment.
23
●
●
Electrical defects.
24
●
●
●
The speed is too high.
25
●
The foundation is not rigid enough.
26
●
The lubricating oil or grease is dirty or
contaminated.
27
Faults
Causes
No. Cause
Remedy
1
The pump is not primed, lack of
priming liquid, incomplete priming.
Fill the pump and inlet pipe completely with pumped liquid.
2
Loss of priming liquid.
Mend possible leaks in the inlet pipe, joints and fittings. Vent the
pump casing to remove accumulated air.
3
The suction lift or static lift is too
high.
Reduce the difference in height between the water reservoir or
water supply and the pump.
4
The outlet pressure is too high.
Make sure that valves in the outlet pipe are fully open.
For parallel operation, this indicates that the outlet pressure is
higher than designed friction losses in the pipes. Review system
design and actual pressure developed in the system with parallel
operation.
5
The speed is too low.
1. Make sure that the motor receives full voltage.
2. Make sure that the frequency is correct.
3. Make sure that all phases are connected.
6
Wrong direction of rotation.
Compare the direction of rotation with the directional arrow on
the pump casing. If required, change the direction of rotation by
interchanging two phases in the motor.