12 | Backup System (Optional) Isotemp -86°C Freezers
Backup System (Optional)
For all ultra-low temperature cold storage products, we
recommend the use of a backup system (BUS) for the
security of your samples.
When you purchase a built-in CO2 or LN2 optional backup
system for the freezer, backup control is integrated into the
main user interface.
Note: For stand-alone backup systems, refer to installation
instructions provided with the backup system kit.
CO2 and LN2 Precautions
The following are precautions for using liquid CO2 and LN2
backup systems.
Installation
Field installed systems are supplied with complete installation
and operating instructions. If your system is factory installed,
the freezer is shipped with a coiled length of hose to connect
the freezer to the bottles:
• 1/4” Flexible Hose with fittings for connection to the CO2
supply.
• 1/2” Flexible Hose with fittings for connection to the LN2
supply.
To install,
1. Straighten the coiled hose.
2. Connect one end to the labeled connection on the
freezer.
• Tighten the nut two flats past finger tight, approximately
120 degrees.
Note: For CO2, remove the threaded fitting from the nut on
the end of the copper tubing to access nut for connection to
the freezer. Discard the threaded fitting.
3. Attach the other end to the supply bottle or building
supply fitting.
• For CO2:
• Remove Nipple from adapter (NPT Connection).
Remove cable tie to release alternative nut and
washer. Ensure the correct nut fitting is supplied over
the nipple (US or European).
Note: Always purchase the cylinders which are
equipped with siphon tubes for withdrawing liquid
from the bottom of the cylinder. CO2 cylinders
must be kept at room temperature to function
properly. LN2 bottles are functional at any
reasonable temperature.
WARNING: If a CO2 or LN2 cylinder falls and a
valve is knocked off, the cylinder becomes a
deadly and completely unguided missile.
Transport the cylinders in a hand-truck or cart
with secure chain ties for the cylinder. After
cylinders are connected to the equipment,
securely attach them with chains to a solid
stationary object such as a building column.
WARNING: CO2 and LN2 liquids are non-
poisonous but are very cold and will burn
unprotected skin. Always wear protective eye
wear and clothing when changing cylinders or
working on the piping systems attached to an
active source of liquid refrigerant.
WARNING: The gases produced by evaporation
of CO2 or LN2 are non-poisonous but displace
the oxygen in a confined space and can cause
asphyxiation. Do not store the cylinders in
subsurface or enclosed areas.
CAUTION: When closing the cylinder valve,
make sure that the injection solenoid is energized
to allow all the liquid to bleed off instead of being
trapped in the supply hose. Failure to do this
results in activation of the pressure relief device,
which could damage the freezer and requires
replacing if it is activated.
CAUTION: For models ordered with factory
installed built-in backup systems, the flow of
liquid CO2 or LN2 will be discontinued if the door
is opened during operation of the backup
system. For units operated with free-standing,
field installed type backup system, the flow of
liquid CO2 or LN2 will be discontinued upon door
opening only if the switch provided with the free-
standing package is installed on the freezer.