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New Brunswick Scientific Co., Inc.
User’s Guide
4.6
General Operating Procedures
WARNING!
Be sure to wear protective gloves at all times when handling
glassware and/or ultra-low temperature items.
4.6.1
After a Power Failure
Should the power supply be interrupted for any reason, the
POWER-FAIL
indicator lamp (Item
e
in Figure 4) will illuminate. In addition, the
audible alarm will sound and the display will flash at approximately 10-
second intervals.
When power is restored, both alarm and light will automatically be
cancelled.
If power has been interrupted for only a short time, the internal
temperature of the freezer will not have risen above the temperature
setpoint (the user-set alarm threshhold), so normal operation will be
resumed immediately.
If, however, the interruption was long enough for the internal temperature
to rise above the temperature setpoint, the
TEMP-ALARM
indicator will
illuminate. If the internal temperature does not fall below the temperature
setpoint within 30 minutes after power was restored, the audible alarm will
sound again. The
TEMP-ALARM
indicator will remain illuminated until
the operator resets it by pressing the
ALARM TEST/MUTE
key.
4.6.2 Interior
Warming
If the lid or door is left open long enough for the internal temperature to
rise above the temperature setpoint, the same effects will be observed as
described in Section 4.6.1 above regarding power failure.
To minimize the risk of this happening, the lid or door should not be
opened more frequently than is absolutely necessary, and then only for the
shortest possible time.
The upright freezers are fitted with internal doors which latch shut,
minimizing temperature rise when the outer door is opened. Inner door
gaskets require the door to be latched at all times when the freezer is
running.
