Manual

54  Error Correction Operating Manual Freeze Dryer ALPHA 1-4 LDplus / ALPHA 2-4 LDplus
Check if the whole surface of the ground-in socket of the mountable
drying chamber has been greased evenly and completely with
vacuum grease.
When using drying chambers with several connections for rubber
valves the valves should be taken off and the connections should
be sealed with rubber stoppers. To check the valves they are
connected one after the other and tested under vacuum.
Check the vacuum sensor for pollution such as water residue.
The vacuum sensor has a limited life time due to its design principle
(see also chapter 7.3.1). Vacuum sensors are available as a spare
part.
Check the vacuum display with a suitable testing unit (if available).
In order to locate a possible leak we recommend that the vacuum
measuring sensor is directly connected to the vacuum flange of the
vacuum pump. If the warm vacuum pump reaches a final pressure
of at least 0.011 mbar, the vacuum pump and the measuring
system can be presumed to be in working order. There is probably
a leak in the unit if insufficient vacuum is not caused by an
insufficient ice condenser temperature.
Check the oil level in the vacuum pump, change oil if dirty, and
carry out a pressure test.
If the above-mentioned steps show no result, the next step is to
check all small flange connections (see chapter 4.7.2) and
especially the position of the centring rings. It is usually not
necessary to grease the sealing rings with high vacuum grease.
The vacuum pump does not switch on:
The vacuum pump is equipped with a protective switch for the drive
motor.
Please refer to separate operating manual.
General information:
The vacuum checks should be carried out when the ice condenser
is deep-frozen.
6.3. Unit does not function
If the display does not work after operating the mains switch, the
following must be checked:
Is the mains switch plugged in?
 Check the on site fuses.
 Check the automatic circuit breaker 1F1 on the back of
the unit.