62 | Preventative Maintenance
Thermo Fisher Scientific CryoExtra CE8100 Series
inside the freezer is higher than actual. Refer Section
for offset adjustment procedure.
4. Observe the audible / visual alarm. Be aware that the
level alarms have a one minute. This delay is intentional
and is to prevent nuisance alarms.
5. If the alarm does not occur after one minute, verify that
the audible alarm is turned on.
6. Decrease the offset value to the original observed setting.
Low Level Alarm Test (Stand Alone Controller
Configuration):
1. Observe and record the current LN
2
level.
2. Remove the vinyl tube from the hose barb on the bottom
of the Controller. Be careful not to damage the tube.
3. The displayed level should drop to 0.0 inches.
4. After one minute, the audible alarm should sound.
5. If the alarm does not sound, verify that the audible alarm
is turned on.
6. Reconnect the vinyl tube. If the tube is deformed at the
end, it may be necessary to trim off ¼
"
of the tube to
ensure a good connection.
7. Press “Fill Start” to purge the level sensing line. After
30 seconds, the level should gradually increase to actual.
8. After the fill cycle is complete, manually measure the level
using the dipstick.
Lid Thaw Procedure
1. Open or remove lid from freezer.
2. It is recommended that the freezer opening be covered
with a spare lid or in another non-airtight manner to
prevent moisture from entering the storage space and to
minimize the top box temperature change while the lid is
open.
3. Allow lid to sit at room temperature for approximately
30 minutes.
4. Once thawed, thoroughly dry lid, cork and liner.
5. Inspect lid for damage and replace parts if necessary.
Folding Step Inspection
CryoExtra freezers equipped with folding steps assemblies
should be inspected for integrity at least every 6 months.
Verify that hinges and free of cracks and all connections are
secure. Check that the anti-slip strips on the steps are in
good condition and replace if necessary (PN 4810179).
Ensure the step locking strap is able to securely hold the
steps in their folded position. If the pivot bolts continuously
loosen, apply thread locker (PN 11087674) and re-tighten.
Inline Filter Replacement
1. Close the LN
2
supply valve and disconnect the LN
2
transfer hose from the plumbing assembly fill tee.
2. Loosen and remove the fill tee and inline filter from the
plumbing assembly.
3. Replace the inline filter (PN 11648945) and reassemble
the fill tee and filter to the plumbing assembly using new
Teflon tape if needed. Ensure the filter is oriented
correctly so that the affixed arrow indicates the direction
of LN
2
flow.
4. Reconnect the LN
2
transfer hose, open the LN
2
supply
valve and check fittings for any leaks.
Complete Function Test
Thermo Fisher Scientific recommends that freezers undergo a
complete function test every 12 months to ensure correct
functionality and identify potential problems before symptoms
develop. Function test documents can be written based on
this manual or this manual itself can be used to verify the
function of CryoExtra freezers.
Solenoid Valve Replacement
All CryoExtra freezers are equipped with electromechanical
solenoid valves that have been tested and approved by
CryoExtra for cryogenic use. These valves utilize a PTFE seal
for optimal sealing in cryogenic environments. Over time, the
normal thermal cycling that this seal is subject to will cause it
to harden and lose its ability to seal completely.
This will result in seepage past the sealing surface which can
increase the LN
2
consumption of the system and in extreme
cases result in an overfill situation. Thermal cycling through
normal operation can also cause moisture ingress into the coil
of the solenoid valve. Over time this may cause the
connections and wiring in the coil to corrode and eventually
fail. This will result in an inoperative solenoid valve.
Note:
Always use replacement solenoid valves from Thermo
Fisher Scientific. Substituting non CryoExtra components may
result in inoperable valves and even damage to the Controller
system. Damage to the control system due to use of non
CryoExtra parts will not be covered by warranty.
CAUTION :
Ensure that the LN
2
supply valve is
closed and the plumbing assembly is vented
before removing the inline filter.
