Thermo Scientific 7400 Series, Operating And Maintenance Manual

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Tank Switcher Outlet
Turn the key switch to Programming Access (.). Press Manual Fill while
checking the tank switcher outlet for line voltage with a volt meter.
When Manual Fill is pressed, liquid nitrogen begins to flow into the
tank. If the LN
2
level is more than one inch below high level setpoint,
liquid nitrogen will continue to flow after Manual Fill is released. If tank
level is less than one inch below high level setpoint, filling will stop
when Manual Fill is released.
LED Test
Turn the unit off. Turn the key switch to Programming Access and turn
the unit on while pressing and holding the Low Level button for four
seconds. Press Manual Fill to begin the test. Turn the unit off, when all
LEDs have cycled, to reset the system.
Remote Alarm Contacts
With the contacts wired to a remote alarm, turn the unit on, wait a few
seconds, then turn the unit off. The alarm should activate immediately.
Manual Fill
Turn the key switch to Programming Access. Press the Manual Fill but-
ton. The fill indicator will light and the unit will begin filling the cham-
ber. If the LN
2
level is more than one inch below the high level setpoint,
the liquid nitrogen will continue to flow after Manual Fill is released
until the high level setpoint is reached. To stop filling before high level,
turn the unit off, then on. If LN
2
is already in the tank and the level is
less than one inch below the high level setpoint, filling will stop when
Manual Fill is released.
Programming Access Test
With the unit turned on, turn the key to Programming Access. The con-
trol panel display will show the high temperature alarm setpoint.
Press High Level, then the up or down arrow. The setpoint moves
accordingly.
Press Low Level, then the up or down arrow. The setpoint moves accord-
ingly. Return the key to Lock. The control panel display shows chamber
temperature and bar graph shows new high and low level setpoints.
Note The unit returns to factory default settings unless setpoints were
saved in above tests by pressing Enter. ▲
1-8 7007400 Cryoplus Thermo Scientific
Section 1
Quick Start-Up
Installation
Verification (cont.)