6
Thermo Scientific Forma Laboratory Refrigerators
Installation and Operation
7
Operation
7.1
Start Up
To start up the refrigerator, complete the following steps:
1. Plug in the power cord.
2. Insert the key in the switch and turn the power on.
3. Rotate the power switch to the ALARM ON position when
the temperature drops below the warm alarm setpoint.
4. Allow the unit to reach operating temperature before loading
it with any product. To stabilize the temperature profile,
a 24-hour waiting period is recommended.
5. After the unit has pulled down to the desired operating
temperature, turn the three position key switch one turn
further clockwise to the Alarm On position. (Space Saver
units have a separate alarm key switch.)
6. If you have a remote alarm, hook it up at this point (refer to
Section 8.3 on page 7).
7. Whether you have a built-in alarm or a customer-installed
remote alarm, you should test it following the instructions in
Section 8.4 on page 7. Alarm setpoints are factory pre-set for
5.5 (warm) and 1.5
°C (cold).
7.2
Product Loading Guidelines
When loading your refrigerator, take care to observe the
following guidelines:
•
Never load the refrigerator beyond capacity.
•
Distribute the load as evenly as possible. Temperature
uniformity depends on air circulation, which could be
impeded if drawers are overfilled, particularly at the top of
the cabinet.
•
For critical applications, be sure that the alarm systems are
working and active before you load any product.
7.3
Automatic Defrost
The defrosting process on all models is primarily accomplished
by air circulated during off-cycle periods.
Under normal conditions, the temperature warm-up during
defrost is virtually unnoticeable. However, an occasional 2
°C
warm-up is possible if usage is heavy and ambient conditions are
extreme.
7.4
Temperature Setpoint Control
Your individual unit has been adjusted and factory tested to
maintain a +4
°C cabinet temperature. For laboratory
refrigerators, cabinet temperature setpoint is a computed value
based on the service parameters Cut On and Differential (see
Table 4 on page 5).
For most applications, however, you will not need to change the
temperature setpoint.
7.5
Interior Light Switch (Glass Door Units Only)
To the right of the control panel is a light switch which operates
independently of the door switch.
If you leave the panel switch in the OFF position, the door switch
will automatically turn on the lights when the door is opened and
turn them off when the door is closed.
If you leave the panel switch in the ON position, the lights will
remain on even when the door is closed.
WARNING!
If you are loading your refrigerator with
light-sensitive product, be sure to leave the light switch
on the control panel in the OFF position.
7
Thermo Scientific Forma Laboratory Refrigerators
Installation and Operation
8
Alarm Systems
8.1
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.
The factory default warm alarm setpoint is 5.5ºC; the default cold
alarm setpoint is 1.5ºC.
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 2 minutes.
The Mute function (pressing the Scan 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.
8.2
Local and Remote Alarms
Refrigerators 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 refrigerator and a remote
alarm depends on the wire gauge used. Refer to Table 5 below.
Table 5.
Wire Gauges and Distance to Remote Alarm
8.3
Installing a Remote Alarm (Optional)
Remote alarm terminals are located at the rear of the machine
compartment. The terminals are: Common, Open on Fail
(Normally Closed), and Close on Fail (Normally Open).
1. The remote alarm system has two keyhole slots on the back
to hang the alarm system on the wall. Insert two screws, no
longer than a #12 truss-head type and spaced two inches
apart, into a wall and mount the alarm.
2. Make the following connections:
a. Connect the common terminal on the cabinet switch to
the purple wire on the alarm.
b. Connect the normally closed terminal on the cabinet to
the black (“open on fail”) wire on the alarm. This
connection gives an alarm when the switch contacts open.
3. Plug the alarm system service cord into an electrical outlet.
This alarm is designed for 115V/60 Hz, 115V/50 Hz, or
100V/50 Hz operation.
Note:
If you want the alarm signal to sound when the switch
contacts close, connect the normally open terminal on
the cabinet to the red/white (“close on fail”) wire on the
alarm. The purple and red/white wires must be tied
together in this application.
The wiring diagram is attached to the inside of the alarm back
cover.
8.4
Alarm Test
Note:
It is important to test your alarm system after any
maintenance operation or temperature control
adjustment.
8.4.1 Theory of Operation
This test procedure applies to both factory-installed built-in
alarms and optional field-installed remote alarms.
During the alarm test, the temperature sensor is artificially heated
and cooled by a tiny, built-in thermoelectric heating and cooling
unit which simulates both warm and cold conditions. The
electronic control module notes the sensor temperature changes
and the control panel displays these changes.
While this alarm testing procedure is very accurate and reliable,
the temperature of the refrigerated space does not change during
the alarm test.
8.4.2 Alarm Test Procedure
Note:
This test automatically advances through all steps and
stops.
1. Verify that the current warm and cold alarm setpoints are
within normal ranges (the warm and cold simulations may
not work if the setpoints are set to extreme values).
2. To start the alarm test, press and Scan simultaneously and
hold for five seconds. During the test the main display and
thermometer bulb will indicate simulated (not actual) cabinet
temperature.
3. When simulated temperature exceeds the warm alarm
setpoint, the alarm sounds and the alarm icon on the control
panel illuminates (#10 in Figure 3 on page 4).
4. The temperature display begins to drop. After a few seconds,
the temperature in the display is back in the operating range.
5. The alarm stops. The temperature on the display drops until
the cold alarm sounds.
6. The test is now complete but the alarm continues to sound
until the temperature on the display is back in the operating
range.
If the simulated alarm conditions do not occur during the first 5
minutes of the alarm test, the service (wrench) icon illuminates
and the test is terminated. You can also terminate the test
immediately by turning the key switch to the second (non-alarm)
position. When during the alarm test, the temperature display
does not change or the service icon illuminates, check the sensor
connections.
After an alarm test has terminated, there is a 10-minute delay
before the test can be run again.
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