Fault
Possible cause
Remedy
❑
Pump does not
start or stops im-
mediately.
➨
Supply voltage is miss-
ing or is too low?
✔
Check or connect electri-
cal supply voltage.
➨
Control signal for motor
speed is missing?
✔
Check control signal.
➨
Overpressure in outlet
line?
✔
Remove blockage in line,
open valve, or reduce
overpressure.
➨
Motor overloaded?
✔
Allow motor to cool down,
identify and eliminate
cause of failure. Manual
reset is necessary. Sepa-
rate pump from supply
voltage.
❑
Pump does not
achieve its ultimate
vacuum or usual
pumping speed.
➨
Centring ring at small
flange connection not
correctly positioned, or
leak in the pipeline or
vacuum system?
✔
Check pump directly -
connect vacuum gauge
directly at pump inlet -
then check connection,
pipeline and vacuum
system if necessary.
➨
Long, narrow vacuum
line?
✔
Use lines with larger di-
ameter, length as short as
possible.
➨
Pump has been ex-
posed to condensate?
✔
Allow pump to run for
some minutes with atmo-
spheric pressure at the
inlet to purge.
➨
Deposits have been
formed inside the
pump?
✔
Clean and inspect the
pump heads.
➨
Diaphragms or valves
damaged?
✔
Replace diaphragms and/
or valves.
➨
Outgassing substances
or vapor generated in
the process?
✔
Check process parame-
ters.
➨
Pump temperature
too high (motor speed
reduced or pump
switched off)?
✔
Ensure sufficient cooling
of the pump or reduce
inlet pressure. Separate
pump from supply volt-
age if the pump has been
switched off.
Troubleshooting
