Eppendorf CO2 Back-up System - Manual (Page 13)

Introduction
New Brunswick CO2 Back-up System
English (EN)
13
5 Introduction
5.1 Scope of manual
This manual provides the user with the necessary information for the installation and operation of the CO
2
Back-up System for New Brunswick Scientific’s Innova ® and Premium -45 and -86 ranges of Ultra Low
Temperature Freezers.
5.2 CO
2
Back-up System
The CO
2
Back-up System system is designed to provide a means of maintaining the contents of a New
Brunswick Scientific Ultra Low Temperature Freezer at a preset temperature should the power or the
refrigeration system fail.
The freezer is fitted with a platinum resistance thermometer (referred to as a temperature sensor or probe)
to measure the internal temperature, a solenoid valve and a door switch.
A freestanding control unit and cables are provided. Transfer lines and connectors are supplied to connect
between the solenoid valve and the CO
2
bottle. Bottles are not provided.
The back-up system is plugged into the power supply and a temperature selected between 0 °C and -70 °C
on the Temp Set dial. When the temperature within the freezer rises above the selected back-up
temperature, the injector switches on. CO
2
gas is released in pulses of approximately two-second bursts,
then a fifteen-second delay.
The solenoid valve continues to inject gas until the temperature within the freezer drops below the preset
value selected on the
Temp Set dial. If a power failure occurs, a battery within the back-up unit will
continue to operate the back-up system for up to 48 hours.
When the door or lid of the freezer is opened, the door switch is activated to prevent additional gas
injections while the freezer is open. This prevents the freezer user from being burned by the extremely cold
gas stream.
NOTICE! Liquid CO
2
required
 Liquid CO
2
is required, NOT gas. Bottles containing liquid CO
2
fitted with full-length dip
tubes must be used.