Note
The internal pressure switches are factory-set and should need no
adjustment for normal operation.
s
There are four pressure switches in the anaerobic cabinet. Two of them are
for gas pressure and two are for vacuum pressure. To adjust the switches:
1. Using a screwdriver, remove the right end panel from the cabinet.
2. The nitrogen pressure switch (for the interchange) and the main
vacuum switch are circular and are mounted upright on the gas and
vacuum lines. To adjust the switches, turn the calibration screw
(mounted on the top of the switch) counterclockwise to increase
pressure or clockwise to decrease pressure.
3. The anaerobic gas and vacuum safety switches are mounted on the
back wall. The left switch is the vacuum safety, and the right switch is
for the anaerobic gas. Turn the calibration screw (located in the center
of the switch) clockwise to increase the pressure or counterclockwise to
decrease the pressure.
The interchange cycle is factory-set at the long cycle; three vacuum
evacuations, two nitrogen purges and one equalizing purge.
For a shorter cycle of two vacuum evacuations, one nitrogen purge and
one equalizing purge, follow the steps below.
1. Using a screwdriver, remove the right end panel from the cabinet.
2. The interchange circuit board is the large circuit board located directly
behind the interchange.
3. In the center of the circuit board,
there is a three-pin jumper connector
marked JP8. The three pins are
numbered. See Figure 4-1. When the
black plastic jumper is over pins 2
and 3 (factory default), the long
interchange cycle is selected. Moving
the plastic jumper from pins 2 and 3
to pins 1 and 2 selects the short
interchange cycle.
4. Reinstall the side panel and restore power to the cabinet.
Anaerobic System 4-5
Thermo Scientific
Section 4
Service
Adjust the Pressure
Switches
Adjust the
Interchange Cycle
Jumper placed over pins 1 and 2
Jumper placed over pins 2 and 3
SHORT CYCLE
LONG CYCLE
SHORT CYCLE
LONG CYCLE
1
2
3
1
2
3
Figure 4-1.
Interchange Board
