Alarm Systems
Thermo Fisher Scientific
Laboratory and Plasma Freezers
13
9 Alarm Systems
9.1 Operating the Alarm
The alarm system is designed to provide visual and audible warning signals
for both power failure and rise in temperature. The alarm is equipped with a
battery backup.
Default cold and warm alarm values are -40
C and -20
C. These values may
be adjusted, following the instructions in Section 6.3.
The alarm system is activated only when the key switch is turned to the
Alarm On position. The audible warning signal sounds when there is a
power failure or temperature alarm condition, or when the door is ajar for
more than 3 minutes.
The Mute function (pressing the button) allows you to turn off the audio
warning without turning off the visual indicators.
To turn off and reset flashing visual alarms, press and simultaneously.
There is also a ringback function after approximately 6 minutes if any alarm
condition remains active.
9.2 Local and Remote
Alarms
Freezer units can have either a factory-installed local alarm or an optional
user-installed remote alarm. Operating and testing procedures are the same
for both types of alarm.
The maximum distance between a freezer and a remote alarm depends on
the wire gauge used. Refer to Table 5 below.
Table 5.
Wire Gauges and Distance to Remote Alarm
Wire Gauge
Total Wire Length (feet)
Distance to Alarm 1/2 Wire
Length (feet)
20
530
265
18
840
420
16
1,330
665
14
2,120
1,060
12
3,370
1,685
