Vogt NM Series, Service Manual, Page: 26 / 30

26
Useful Tips
Useful Tips
for trouble-free operation
9. 3 Pump Overloads Motor
9 .4 Abnormal Vibrations of Pumping Equipment
Possible Causes Solutions
1.- The pumped liquid has a viscosity or density
different from that for which the pump was
selected.
· Check and consult the manufacturer.
2.- There are mechanical defects (moving parts
rubbing against fixed parts).
· Check and consider a pump repair.
1.- The pump is not primed.
Possible Causes
Solutions
2.- Air enters the suction pipe.
· Check and complete the filling of the system with
liquid.
· Check and repair damaged ducts and
defective joints.
3.- The suction lift is too high (insufficient NPSH).
· Check that NPSHavailable > NPSHrequired
· Check suction geometric head.
· Check head losses in the suction pipe (partially
closed valve, foreign bodies).
4.- The impeller is partially clogged causing
unbalance.
· Check and clear blockages.
· Check bearings for damage.
5.- There are mechanical problems, such as bent
shaft, seized parts.
· Check and consider repair.
9 . 5 Pump Breaks Down After Start-up
Possible Causes
Solutions
1.- Leaks in the suction line.
· Check and repair damaged ducts and
defective joints.
2.- The suction height is too high.
· Check suction height and consult the
manufacturer.
3.- The foot valve or pipe is not sufficiently
submerged.
· Check and submerge as necessary.