17
Pump NB/FB/WP/SM/F
Version: 27216 - E
Schmalenberger GmbH + Co. KG
D-72072 Tübingen / Germany
3.5
Troubleshooting
Pump stopped
Flow rate of the pump is too low
Motor overload
Pump end press
u
re too high
Increased bearing temperature
Pump leaking
Pump not running quietly
T
e
mp
e
rature of pum
p is
t
oo high
Oil level indicator too high / too low
Cause of the malfunction
To eliminate the malfunction
X
Pressure against which the pump is
pumping is too high
Readjust the operating point
X
Counter pressure too high
System contaminated
Reduce the gap between the wear plate and
the open impeller.
Install a new impeller (*)
X
X X
Pump / pipelines not fully vented
Vent and fill with liquid
X
Supply or impeller blocked
Eliminate the cause in the pipeline or pump
X
Air lock formation in the pipeline
Change pipeline or install new venting valve
X
X X
Suction lift too great / NPSH system
too low (supply)
Correct fluid level/level control.
Install pump lower, fully open fittings in the
suction line, reduce the resistance of the
supply line, clean the sieves and suction
connection.
X
Non-return flap does not open
Check the non-return flap, venting line
immediately before non-return flap
X
X X
Wrong direction of rotation
Reverse 2 phases in the terminal box
X
Speed too low
Increase speed (*) (new motor may be
required)
X
X
Worn internal parts (for example
impeller), foreign objects in the pump
Replace worn parts, remove foreign objects
from the pump housing
X
X
Counter pressure is lower than what
is indicated in the design
(specification).
Reset the operating point precisely, throttle
to increase counter pressure, screw out
impeller if necessary (*), larger motor (*)
X
Density or viscosity of the pum-
ping medium is higher than speci-
fied
(*) (Pump must be retuned)
X
Shaft seal worn or
Sealing ring faulty, sealing ring old,
dry running
Check the sealing liquid level.
Replace the shaft seal.
Replace the seal
X
X
Motor connected incorrectly
Circuit diagram, see section 2.3.4, observe
instructions
X X X
Pump poorly aligned
Align accurately
X X X
Pump braced or resonance
vibrations in pipelines
Check pipeline connections or pump
fastenings, connect pipelines with
compensators.
X
Increased axle thrust
Clean the relief holes in the impeller
X
X
Bearing faulty; not enough, too much
or the wrong lubricant
Replace bearing, add or reduce lubricant or
replace completely
X
Connection distance not observed
Adjust distance correctly
X X
Motor running on 2 phases
Check/repair fuse and line connections
