Ultra Low Temperature Freezers Backup System (Optional) | 31
Backup System (Optional)
When you purchase a built-in CO
2
or LN
2
optional backup
system for the freezer, backup control is integrated into the
main user interface.
CO
2
and LN
2
Precautions
The following are precautions for using liquid CO
2
and LN
2
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 inches Flexible Hose with fittings for connection to
the CO
2
supply.
• 1/2 inches Flexible Hose with fittings for connection to
the LN
2
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 CO
2
, 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 CO
2
:
• 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).
• Add 2 wraps of Teflon tape clockwise to the
1/4 inches NPT fitting (on the nipple) when viewed
from the threads. Tighten the NPT fittings
approximately 2 turns from finger tight (approximately
720°).
Note: Always purchase the cylinders which are
equipped with siphon tubes for withdrawing
liquid from the bottom of the cylinder.
CO
2
cylinders must be kept at room
temperature to function properly. LN
2
bottles
are functional at any reasonable temperature.
WARNING: If a CO
2
or LN
2
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: CO
2
and LN
2
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 CO
2
or LN
2
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,
ensure 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 CO
2
or LN
2
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 CO
2
or LN
2
will be discontinued upon
door opening only if the switch provided with
the free-standing package is installed on the
freezer.
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