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New Brunswick Scientific
User’s Guide
3.7 Vacuum
Effect
After closing the door or lid of the freezer, following access to the contents, a vacuum may
be created by the contraction of the warm air that entered the freezer. Before the door can be
opened again, it may be necessary to wait two or three minutes for the vacuum to be released
by the vacuum release vent tube. Do not try to force the door or lid.
During the release of the vacuum, a slight hissing may be heard. In order to minimize
vacuum formation, the vent contains a heater assembly to prevent ice buildup inside the vent
tube and has a spring-loaded plunger to clear ice from the internal opening of the vent.
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NOTE:
Be careful not to place a rack directly against the vent, as this will inhibit
the vent/plunger’s ability to operate correctly (see Section 5.1.4).
