8
Thermo Scientific Jewett Blood Bank Refrigerators
Installation and Operation
10 Chart Recorders
Panel-mounted six inch recorders are standard and factory-
installed on all models except for undercounter models, for
which free-standing recorders are available as options.
Recorder operation begins when the system is powered on.
10.1 Set Up and Operation
To prepare the recorder to function properly, complete the
following steps:
1. Open the recorder door to access the recorder.
2. Connect the nine volt DC battery located at the recorder’s
upper right corner. This battery provides back-up power.
3. Install clean chart paper (refer to Section 10.3 below).
4. Remove the plastic cap from the pen stylus and close the
recorder door.
Note:
The recorder may not respond until the system reaches
temperatures within the recorder’s range.
Figure 5. Six Inch Chart Recorder
Figure 6. Chart Buttons
10.2 Power Supply
The recorder normally uses AC power when the system is
operating. If AC power fails, the LED indicator flashes to alert
you to a power failure. The recorder continues sensing cabinet
temperature and the chart continues turning for approximately
24 hours with back-up power provided by the nine-volt battery.
The LED indicator glows continuously when main power is
functioning and the battery is charged.
When the battery is low, the LED flashes to indicate that the
battery needs to be changed.
10.3 Changing Chart Paper
To change the chart paper, complete the following steps:
1. Locate the pressure sensitive buttons at the front, upper left
of the recorder panel.
2. Press and hold the change chart button for one second. The
pen will move off the scale.
3. Unscrew the center nut, remove the old chart paper, and
install new chart paper. Carefully align the day and time with
the reference mark on the recorder panel (a small groove on
the left side of the panel, shown in Figure 5).
4. Replace the center nut and hand tighten. Press the change
chart button again to resume temperature recording.
10.4 Calibration Adjustment
This recorder has been accurately calibrated at the factory and
retains calibration even during power interruptions. If required,
however, adjustments can be made as follows:
1. Run the unit continuously at the control setpoint temperature.
Continue steady operation for at least two hours to provide
adequate time for recorder response.
2. Measure cabinet center solution temperature with a
calibrated temperature monitor. (Solution temperature is
measured inside the sensor bottles — see Section 8.2.)
3. Compare the recorder temperature to the solution
temperature. If necessary, adjust recorder by pressing the left
(#1) and right (#2) chart buttons.
Note:
The stylus does not begin to move until the button is held
for five seconds.
9 Volt Battery
Imprinting
Stylus
Hub-Nut and
Retaining Wire
Chart
Chart Buttons
Reference Mark
1
2
3
CHANGE CHART
