VWR 5700 Series, Руководство по эксплуатации и техническому обслуживанию, Страница: 37 / 90

The optional back up system is designed to inject CO2 or LN2 into the
freezer compartment if the temperature rises above back up system set
point. To set the BUS set point:
1. Press the Mode key until the Settings indicator lights.
2. Press the right arrow until “BACKUP = -XX” is displayed in the
message center.
3. Press the up or down arrow key until the desired BUS set point is
displayed.
4. Press Enter to save the setting.
5. Press the Mode key until the Run indicator lights or press the right or
left arrow to go to the next or previous parameter.
If no control keys are pressed, the freezer will automatically return to Run
mode after 5 minutes.
Warning Changing the operating temp setpoint can affect the BUS
setpoint. The BUS setpoint will self-adjust to maintain a temp of at least
10°C above the operating temp setpoint.
s
Caution The BUS setpoint cannot be set any colder than the high temp
alarm setpoint. (See Sect. 1 - Set High Temperature Alarm). If the back-up
system is installed with CO
2
, then -65°C is the coldest BUS setpoint that
can be used (if cabinet setpoint is -75°C or colder).
s
After the freezer has stabilized and both batteries are fully charged, the
BUS can be tested to verify proper operation.
1. Disconnect the AC power to the freezer by turning power switch off.
2. As the freezer warms up, verify the BUS injects at the desired
temperature. Displayed temperature may vary by a few degrees from
inject temperature due to the differences in probe locations.
To disconnect the freezer back-up from the gas supply:
1. Close the supply valve.
2. Depress the test button on the Back-Up System control box to remove
the gas from the line.
3. Slowly disconnect the fitting assembly from the supply (in the event
that any gas remains in the line).
5-6 ULT Freezer VWR International
Section 5
Factory Installed Options
Set Optional BUS Set
Point
Disconnect Fitting
Assembly, Transfer Hose
Test the BUS