Faults
30 EN
04/2019
Fault
: Too low a flow rate in the pump
Possible cause
Solution
Pump is handling against
too high a discharge
head.
Set operating point again.
Check unit for impurities.
Pump and pipes not
completely ventilated or
filled.
Ventilate
pump.
Fill
pump.
Pump/pump parts
blocked due to
impurities.
Clean.
Building up of air sacks
in the piping.
Modify piping or insert a
ventilation valve.
Suction height too
large/Unit’s NPSH
(intake) too low.
Correct
the
fluid
level.
Install
pump
lower.
Completely open shut-off valve
in the intake line.
If the resistance is too large,
modify the intake line.
Check
suction
basket/suction
opening.
Observe the permitted pressure
reduction speed.
Drawing in air in the
mechanical seal.
Replace
mechanical
seal.
Incorrect direction of
rotation (3~).
Check
the
electrical
connection
to the motor and switching
device.
Too low a speed.
Increase the voltage/frequency
on the frequency converter
within the permitted range.
Wear of components.
Replace
components.
Running on two phases.
Renew faulty fuse.
Check
the
electrical
connections
using the operating manual.
