Operation Of Level Monitor - Thermo Scientific Locator Series Operation Manual And Parts List

A L N
CCESSORY IQUID
Note
Important: The Level Monitor may take
up to 10 minutes to establish a read-
ing after the unit is placed on the cry-
ovessel. Remember to press "Reset"
after placing unit on the vessel. The
green LED on the switch should be
"OFF."
16
L M
ITROGEN EVEL ONITOR
O
PERATION
is dangerously low, and you are alerted to re-fill
the vessel immediately.
3. The 5 segment LED display becomes lit and an
audible alarm sounds continuously when the
LOCATOR or LOCATOR Plus vessel has no
more liquid nitrogen or if the level inside the
vessel is falling at a rate of 1/2" per hour or
more. In this situation, you are alerted that an
emergency exists. Either there is no more liquid
nitrogen inside the LOCATOR or LOCATOR
Plus vessel, or the level of liquid nitrogen is
dropping rapidly, due to a vacuum failure of the
LOCATOR or LOCATOR Plus vessel.
Safety Feature
A "RESET" switch lights and an audible alarm sounds
intermittently if the user does not reset the monitor after
removing vessel cover. The microprocessor must be reset
each time the cover is removed from the LOCATOR or
LOCATOR Plus.
Before removing the cover, the reset button must be
pushed, illuminating the reset light. While in this
reset/hold mode, the monitor is not sensing. After five
minutes in the reset/hold mode, an audible alarm will
sound, alerting you to deactivate the reset/hold mode and
replace the cover on the vessel.

Operation of Level Monitor

Once the cover with the monitor has been placed on the
vessel and plugged in, it will take the system about 15
minutes to equilibrate before an accurate measurement of
the liquid nitrogen will be indicated. This equilibration
process will occur each time the vessel is used. Each
time a vessel is opened, the stabilized chamber tempera-
ture is disrupted. The system requires a stable tempera-
ture to determine an accurate liquid nitrogen level.
If you have just purchased a new LOCATOR or LOCA-
TOR Plus along with your monitor, allow at least 1 day for
the liquid nitrogen to equilibrate the vessel before plug-
ging in the unit. This will avoid false alarms.