Forma Laboratory Refrigerators 34830H63 Rev. A a & d voltages

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.

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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

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