14
New Brunswick Scientific Co., Inc.
User’s Guide
3.1.2 Testing
Injector
Valve & LED Operation
1.
Turn off the backup system power switch.
2.
Turn on the freezer, set the freezer temperature as required, then wait until the
freezer has reached the preset temperature.
3.
Set the LN
2
backup unit to a warmer temperature than the freezer’s actual
temperature, then turn the backup system power switch on. The Temperature
Warning and Valve Open lights should remain off.
4.
Push and release the Valve Test button. The Valve Open light will illuminate
and LN
2
should be injected into the freezer.
5.
When you release the Valve Test button, the front panel LEDs will illuminate
in sequence, in a clockwise direction.
WARNING!
The Valve Test button should only be used for short periods (1-2 seconds)
to test valve operation. Continuous operation can result in pressurizing the
cabinet.
3.1.3
Testing Backup System Operation
1.
Change the backup unit temperature setting to 10
o
C colder than the freezer’s
actual temperature. The Temperature Warning and Valve Open lights should
come on. The Valve Open light will illuminate to indicate that gas is being
injected to cool the freezer.
2.
Unplug the backup unit’s power cord from the power supply. The Power On
light should go out, but there should be no change in the Temperature and
Valve On indicator lights on the front of the unit, because the unit is now
operating on battery backup.
3.
Plug the backup unit’s power cord into the power supply.
4.
Reset the backup system to the desired temperature at which the backup unit
should turn on in an emergency power situation. It is recommended that you
set the backup unit temperature to 10° C warmer than the freezer’s desired
setpoint.
5.
Verify that the gas supply is still on, the freezer is operating at its setpoint and
the backup unit is plugged in, turned on, and set to the desired setpoint. The
Temperature Warning and Valve Open lights should be off and the power
light on.
Upon successful completion of all of the above tests, your LN
2
backup unit has
now been installed and set-up, and is operating normally.
