Error Correction; Power Failure; Insufficient Vacuum - Fisher ALPHA 1-2 LDplus Operating Manual

6. Error Correction

6.1. Power Failure

6.2. Insufficient Vacuum

Operating Manual Freeze Dryer ALPHA 1-2 LDplus
The control system continues the process after a power failure. The
preselected conditions remain saved during the process run. The
process times, the total time and the section time are reset.
In the event of a power failure during the drying process the batch
may become unusable. Whether the batch can be saved depends on
the drying phase in which the product was when the power failure
occurred.
It is important to distinguish between the main drying and final drying
phase:
The product is in the final drying phase when the residual moisture
has reached approx. 5 %. Below this value the product is generally
not damaged in the event of a power failure.
If the product is in the main drying phase we recommend that the unit
is vented, the product taken out and stored in a deep-freeze. Before
further operation the defrosted condensate must be drained.
Special attention must be paid to the high-vacuum valves. The drain
valve, the micro-aeration valve and the rubber valves must be
checked.
We recommend that after disconnecting the mains plug the left side
panel of the unit is unscrewed and then the hose inside the unit is
detached from the drain valve, the pipe connection is sealed with a
rubber stopper, and the unit evacuated. If the unit will now reach the
necessary operating pressure there is a leakage in the valve. This is
caused by residue from the drying process, fluff from cleaning cloths
or wear and tear of the O-rings of the valve.
Error Correction • 49