9
Thermo Scientific Harris Ultra-Low Temperature Freezers
Installation and Operation
7 Operation (ELT Freezers)
7.1
Control Panel Features
Before the initial start up, take some time to become familiar with the controls on your freezer. Figure 6 illustrates the Harris ELT Series
Chest and Upright Freezer control panel.
Figure 6. Harris ELT Series Control Panel
1. Keyed Power On/Alarm On switch.
2. LED digital temperature display.
3. Recessed temperature control set point adjustment.
4. Temperature set point adjust button.
7.2
Start Up
Refer to Figure 6 as you complete the following procedures.
7.2.1 Turning the Power On
To start up the Harris ELT Series Freezer, complete the following steps:
1. Plug the freezer into the power outlet (refer to Section 4.2 on page 2).
2. Turn the key switch to the POWER ON position. The digital temperature display shows the cabinet temperature.
Note:
The alarm function is not active at this time.
7.2.2 Setting the Cabinet Temperature
To set the cabinet temperature, complete the following steps:
1. Insert a small screwdriver into the slotted screw labeled Control Set Point and simultaneously press and hold the Set Point Display
button. The temperature display changes to read the existing set point value.
2. Turn the set point screw (clockwise for a colder setting and counterclockwise for a warmer setting) until the desired set point shows
in the digital temperature display.
3. Release the Set Point Display button. The digital temperature display returns to the cabinet temperature.
7.2.3 Alarm
The Harris ELT’s Alarm is operated by the freezer electronic control system. The alarm is preset at the factory with a cold set point:
•
For units designed to operate at -75
°
C and -85
°
C, the alarm set point is approximately 90% of the freezer temperature set point. For
example, if the freezer set point is -80
°
C, the alarm set point is -72
°
C.
•
For units designed to operate at -50
°
C and warmer, the alarm set point is 80% of the freezer temperature set point. For example, if
the freezer set point is -40
°
C, the alarm set point is -32
°
C.
To activate the alarm, wait until the freezer reaches operating temperature and turn the key switch to the ALARM ON position.
WARNING!
You must turn the three-position key switch to the ALARM ON position to activate the alarm and place it in
operation.
1
3
Power
OFF
°
c
POWER ON
ALARM ON
CONTROL
SET POINT
SET POINT
DISPLAY
With
VOLTAGE BOOST
4
2
