Martin Christ Alpha 2-4 LDplus - Manual (Page 55)

Operating Manual Freeze Dryer ALPHA 1-4 LDplus / ALPHA 2-4 LDplus Error Correction 55
6.4. Insufficient Ice Condenser Temperature
The refrigerator is equipped with a protection device against
overpressure in the refrigerating system and with a thermal motor
protection.
The protection devices are released
with too high ambient temperatures,
with insufficient air circulation of the heat exchanger of
the refrigerating system,
with overload of the refrigerating system.
The refrigerating system is switched off automatically.
Once the permissible operating conditions are reached again (after
a few minutes), the refrigerator is switched on automatically via the
motor protection switch or via the pressure protection device.
Important errors are shown in the process and equipment
information system.
The minimum ice condenser temperature of approx. -55°C
respectively -85°C is reached if the ice condenser is not loaded and
the ice condenser chamber is evacuated.
Sufficient air circulation is necessary. Do not deposit any objects
behind the freezing unit!
6.5. Process and Equipment Information System
6.5.1. Error Messages
Vacuum of 6.11 mbar has not been reached
This error occurs in case the pressure in the ice condenser chamber has
not reached 6.11 mbar after 15 minutes of operation with open pressure
control valve. There must be a vacuum leak in the system. The pump is
switched off to avoid it pumping against the atmospheric pressure.
The pressure control valve is closed and the vacuum pump is switched off.
Please eliminate the error and confirm the message afterwards. Following
the confirmation, the vacuum pump is restarted.
Causes:
Micro-aeration valve or drain valve not closed.
Lid or drying chamber not mounted correctly.
Missing ground-in stopper in the lid or in the drying chamber.
Defective vacuum pump. Check whether the mains switch of the vacuum
pump is switched on.