Rubber Valves - Fisher ALPHA 1-2 LDplus Operating Manual

(see below). We recommend a warm-up phase of at least 5 minutes
before the adjustment.
Buttons with protective caps
for adjusting the sensor
7.3.2.2 Adjustment to a specific zero reference value
To perform this adjustment, the actual pressure must be lower than
-2
1.0x10 mbar. After pressing of the button labelled "set", the actual
vacuum field of the LDplus control system shows a value
corresponding to the zero adjustment value currently set (factory
setting 0.0010 mbar). The button labelled "adj" can now be used to
-2
increment this value up to a maximum of 1.0x10 mbar. As of this
value, the output starts again at 0.0010 mbar. When the zero
adjustment value is adapted to the applied zero reference value, the
new zero reference value will be saved automatically and without any
other key depression after 5 seconds and the adjustment will be
performed. If from now on the "adj" button is pressed at zero
pressure, the system will be adjusted to the zero adjustment value
set.
If "set" is entered without any other key depression, the zero
adjustment value will be shown in a purely informative manner for 5
seconds, but no adjustment will be performed.

7.4. Rubber Valves

Special attention must be paid to the rubber valves. If the valves are
stiff, they must be dismantled, cleaned, slightly greased with vacuum
grease and reassembled.
Maintenance • 57
Operating Manual Freeze Dryer ALPHA 1-2 LDplus