A vane is blocked in the rotor or otherwise
damaged
Free the vanes or replace with new ones
(Busch service)
The radial clearance between the rotor and
the cylinder is no longer adequate
Readjust the vacuum pump (Busch service)
Internal parts are worn or damaged
Repair the vacuum pump (Busch service)
Version with oil return line to the suction connection (RC ... C):
The oil return line starts in an area vented to atmospheric pressure. Particularly on small model
pumps, a fairly large amount of air is sucked through the oil return line, which may prevent the
ultimate pressure from reaching 20 bar abs.
In order to exclude this possible cause:
either
temporarily disconnect the oil return line from its connection near the exhaust opening and
close it
or
squirt oil through the gas discharge (g)
The gas conveyed by the vacuum pump smells
displeasing
Process components evaporating under vac-
uum
Readily volatile and thus gaseous components
of the oil, e.g. additives, particularly right after
an oil change.
Note
: This is no indication of a malfunction of
the oil separator. The oil separator is able to
retain droplets of oil, however no gaseous
components of it.
Check the process, if applicable
Use a different type of oil, if applicable
The vacuum pump does not start
The drive motor is not supplied with the cor-
rect voltage or is overloaded
Supply the drive motor with the correct volt-
age
The drive motor starter overload protection is
too small or trip level is too low
Compare the trip level of the drive motor
starter overload protection with the data on
the nameplate, correct if necessary
In case of high ambient temperature: set the
trip level of the drive motor starter overload
protection 5 percent above the nominal drive
motor current
One of the fuses has blown
Check the fuses
Version with alternating current motor:
The drive motor capacitor is defective
Repair the drive (Busch service)
The connection cable is too small or too long
causing a voltage drop at the vacuum pump
Use sufficiently dimensioned cable
The vacuum pump or the drive motor is
blocked
Make sure the drive motor is disconnected
from the power supply
Remove the fan cover
Try to turn the drive motor with the vacuum
pump by hand
If the unit is still frozen: remove the drive mo-
tor and check the drive motor and the vacuum
pump separately
If the vacuum pump is blocked:
Repair the vacuum pump (Busch service)
The drive motor is defective
Replace the drive motor (Busch service)
The vacuum pump is blocked
Solid foreign matter has entered the vacuum
pump
Repair the vacuum pump (Busch service)
Make sure the suction line is equipped with a
screen
If necessary additionally provide a filter
Corrosion in the vacuum pump from remain-
ing condensate
Repair the vacuum pump (Busch service)
Check the process
Observe the chapter Conveying Condensable
Vapours (
Ú
page 8)
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