Bio-Rad CHEF-DR II System - Manual (Page 8)

5.3 Operation
After the Cooling Module has been connected, the following steps should be followed for
optimal operation.
1) Switch on the recirculating pump, and adjust flow rate to 1.0 liter/minute (setting of 70–80).
2) Switch on the Cooling Module (main power switch is on the front panel of the unit). The
temperature display will read “14.0” after ten beeps, indicating that the unit is on
(Figure 3A), and the red light above the “SET TEMP” button will illuminate (Figure 3B).
3) Enter the desired run temperature (14 °C is recommended) by pressing the “LOWER” or
“Raise” button (Figure 3F) until the desired number is reached.
4) After 100 seconds have elapsed, the compressor will engage (if the set temperature is
below ambient temperature), and the red light above “COOLING” will illuminate (Figure
3D). This 100 second delay allows pressure equalization in the system to avoid
mechanical damage.
5) Press the “ACTUAL TEMP” button (the red light above the button will illuminate; Figure
3C) to read the current temperature monitored at the internal temperature probe (located
in the “FLOW OUT” port), or at the Cell’s internal temperature probe (if connected).
6) After the Cooling Module has cooled the buffer to the desired set temperature, the “COOLING”
light will occassionally go on and off accompanied by a click. This is an indication of
the refrigerant bypass valve cycling on and off to maintain average buffer temperature
within 1 °C of set temperature. Greater temperature fluctuations may occur with longer
tubing length, low buffer flow rates, and/or high amounts of input power and high
ambient temperatures. However, the built-in adaptive algorithm will compensate for these
conditions so that the average temperature is typically within 1 °C.
NOTE: Please allow sufficient room for ventilation at both the front and rear of the unit.
The cooling fan is located in the rear.
Fi.g. 3. Control panel of Cooling Module. A. Digital display (3 numerical places plus decimal point).
B. Temperature set button and indicator light C. Actual temperature button and indicator light.
D. Compressor running light. E. Raise button. F. Lower button.
5
A
B C D E F