Specifications

Operating Manual Freeze Dryer ALPHA 1-4 LD-2 / 2-4 LD-2, Version 0203, Page 39
6.5 Condenser of Cooling Liquid
A laminated condenser for cooling liquid is used to cool the refrigerant compressed by
the refrigerator. The condenser for cooling liquid is placed at the bottom of the unit. In
intervals of a few months it must be checked for dust or dirt residues and cleaned if
necessary. Cleaning of the heat exchanger can be carried out best by brushing, by
using a vacuum cleaner from the outside or by using compressed air from inside the
unit.
Excessive dirt on the condenser for cooling liquid leads to a decrease in performance
and can lead to a failure of the unit!
Please note: The unit must not be turned upside down!
6.6 Adjustment of the Vacuum Measuring Sensor TPR 265
Adjustment of the vacuum measuring sensor should be carried out at least once a year
if the unit is used continuously. Otherwise the operating point of the measuring sensor
can change, e. g. "800 mbar" is indicated instead of "A" (atmosphere).
For adjustment of the sensor, two values must be set:
"A" = Atmosphere
"HV" = High-vacuum
The high-vacuum range of the sensor is more stable so that a adjustment is in most
cases only necessary for atmosphere.
"A" Adjustment:
− Insert the plug of the sensor TPR 265 into the socket at the rear panel of
ALPHA 1-4 LD-2 / ALPHA 2-4 LD-2, switch on the unit and preselect the vacuum
display.
− Switch on the vacuum pump and let it warm up for approx. 15 minutes.
− Mount the TPR 265 on the vacuum connection piece of the vacuum pump.
− Switch on the vacuum pump and evacuate for approx. 3 minutes, then vent the unit
slowly.
− Wait for approx. 10 minutes. For the adjustment of the atmospheric value it is
important that the TPR 265 must be in exactly the same place as it will be used in
later!
− Press the conversion button "=" of ALPHA 1-4 LD-2 / ALPHA 2-4 LD-2 and set the
transition point in the display from "A-FF" to "A-or" (i. e. between "FF" and
"Overrange") using the potentiometer "ATM" of the TPR 265.