Technical data

automatically after the set defrosting time (see VALUES Æ Set
Values for Manual Mode).
It is not possible to start the defrosting phase during an active
phase (freezing, main drying, final drying). The unit has to be in
the standby mode. During the defrosting process, it is not possible
to select any of the other phases (freezing, main drying, final
drying). In this case it is also necessary to switch the unit to the
standby mode first. In addition, it is important that the chamber is
completely vented, i.e. the actual vacuum value must be "Atm".
Fig. 26 Dialog box for manual defrosting
5.4.5. Manual pressure increase measurement (optional)
Select (MANUAL Æ Special Functions Æ Pressure inc.
measurement)
to activate the manual measurement of the
pressure increase. This feature is only available in the “Run”
mode of the main drying phase or in the “Run”
mode of the final
drying phase.
Fig. 27 Dialog box for the manual pressure increase measurement
Press to start the pressure increase measurement. During
the measurement, the intermediate valve prevents the flow of
vapor from the drying chamber to the ice condenser. The pressure
difference is displayed in accordance with the vapor pressure
curve above ice.
The pressure difference is calculated as follows:
Operating Manual Freeze Dryer ALPHA 1-4 LSC / ALPHA 2-4 LSC LSC Control System • 53