Section 7
LN2 Level Monitor
Troubleshooting and Parts List
Cryogenic Storage Vessel
7-1
Thermo Scientific
Problem
Cause
Solution
Level monitor alarm sounds
intermittently. Unit measuring liquid
level incorrectly.
Ice or frost buildup on the
transducer.
Remove the cover w/ monitor from vessel and place in room for approx-
imately two hours, or until no ice is visible on the transducer or tube.
NOTE: Do not use an external heat source (i.e. heat gun) to accelerate
the thawing process as it can damage the cork. Make sure lid is stand-
ing upright on the cork to allow moisture to drain out of cover w/ moni-
tor. Wipe any moisture away from the inside of the tube and face of the
transducer with a clean soft cloth. Place cover w/ monitor back on unit.
(Remember to press “Reset” button.)
Level monitor measuring “Full” after
removing samples and replacing lid.
Fog in top part (neck area) of
cryogenic vessel.
The density of the fog that is formed after removing the lid and access-
ing samples is dependent on the humidity of the room where the cry-
ovessel is located. The fog dissipates after about fifteen minutes and at
this time, the level monitor will take an accurate reading of the liquid
nitrogen level.
Ordering Procedures
Refer to the Specification Plate for the complete model number, serial
number, and series number when requesting service, replacement parts or
in any correspondence concerning this unit.
All parts listed herein may be ordered from the Thermo Scientific dealer
from whom you purchased this unit or can be obtained promptly from the
factory. When service or replacement parts are needed, check first with
your dealer. If the dealer cannot process your request, then contact
Technical Services.
Prior to returning any materials, contact our Technical Services
Department for a “Return Materials Authorization” number (RMA).
Material returned without an RMA number will be refused.
Caution - Preventative Maintenance
Depending on environmental
conditions and the number of lid openings, the lid should be periodically
inspected for ice and frost buildup. Refer to chart below.
s
