MEGACHEM
12
Faults-cause & remedy
10
Pump deliver
s insufficient liquid
M
otor
over
loaded
Excessively high pump dischar
ge
pr
essur
e
B
ear
ings over
heating
Pump leaks
Excessive shaft sealing leakage
R
ough pump running
Excessive temper
atur
e r
ise
inside the pump
Cause Remedy
1)
•
The pump generates excessively
high differential pressure
Reset duty point
•
Excessively high back pressure
Check the plant for dirt. Fit larger
impeller 2)
•
•
•
The pump and \ or piping are
incompletely vented or primed.
Vent or prime the pump and piping
completely
•
Suction line or impeller clogged
Remove the deposites in the pump
and / or piping
•
Formation of air pockets in the
piping
Alter piping lyout. If necessary, fit a
vent valve
•
•
•
NPSH avaliable is too low (on
positive suction head installations)
Check the liquid level. Mount the
pump at lower level. Open isolating
valve in the suction line fully. Alter
suction line, if the losses in the
suction line are excessive.
•
Ingress of air on shaft seal
Sealing liquid passage is clogged;
clean it out. If necessary, arrange a
sealing liquid supply from an outside
source, or increase sealing liquid
pressure. Fit a new shaft seal \ gland
packing.
•
Reverse rotation
Change over two phases of the
power supply cable.
•
Rotational speed is too low 2)
Increase the speed
•
•
Excessive wear of the pump
internals
Repalce worn components by new
ones.
•
•
Pump back pressure is lower than
that specified in the purchase
order.
Adjust duty point accurately. In case
of persistant overloading, trim the
impeller, if necessary.2)
•
Specifc gravity or viscosity of the
fluid pumped is higher than that
specified in the purchase order.
2)
