Defy Upright Refrigerator Service Manual download pdf (Page 44)

[Bulletin

R61/7A

continued)

B.

1.

3

3.

4.

PERFORMANCE

TEST

First perform

all the preliminary

checks

described previously.

Remove all food from the refrigerator and

place all controls in the OFF position.

Place an accurate thermometer in an ice

cube tray, half filled with water, and place

the tray in the center of the lower food

storage compartment. NOTE: If a

remote-

reading thermometer

is

used (allowing

temperature readings without opening the

door) the tray of water is not required.

Make sure the AC heating element is the

correct wattage for the model being tested,

and that the resistance reading is correct.

(See

“Checking Resistance of a Heating

Element” below.)

Connect 120 volt AC power directly to

the heating element leads (make sure the

leads are not connected to the refrigerator

circuit),

then check

the voltage at the

element with a volt meter.

Reading must

show at least 115 volts.

CHECKING RESISTANCE OF

A

HEATING

ELEMENT

A simple test to check a heating element is to

measure

the resistance through

the element

with an ohmmeter.

The correct resistance, in

ohms,

can be calculated if the wattage and

voltage ratings are known.

(These ratings are

stamped on all

Dometic

heating elements.)

Use this Formula:

Volts

+

(Watts

+

Volts) = Ohms

Example:

Heating element rated 135 Watts at 110 Volts.

110

f

(13.5

f

110) or,

110

+

1.23 = 89.4 ohms

The ohm reading should be within 10% of this

figure, or between 80.46 and 98.34 ohms.

Use

the lowest setting on the ohmmeter which will

give an accurate reading.

When testing a 12 volt heating element, a

very accurate ohmmeter must be used because

of the very low readings that will be found.

For example,a 200 watt element will have a

reading of

.72

ohms (less than 1 ohm).

5.

After two hours of operation, check

temperature on the back of the cooling

with your hand, at the locations shown.

FIG.

Bl

(TEMPERATURE

TEST AREA)

the

unit

CONDENSER

i3OBR

ENCLOSURE

(TEMPERATURE

TEST AREA)

Under normal operation the temperature at

the absorber coils (A) and the boiler (B)

should be approximately the same.

If the

temperature at the absorber coils (A) is

much hotter it indicates loss of refrigerant

and the cooling unit must be replaced.

If

the temperature at the boiler (B) is very hot

and the absorber coils (A) are cool it indicates

that the refrigerant is not circulating properly.

This could indicate:

A. Liquid trapped in the evaporator sections,

caused by out-of-level operation for a

period of time.

Resetting the refrigerator

to a level position will not necessarily

correct the problem as liquid can remain

trapped even after level is corrected.

Shut off the heat source and let the

system cool down,

then re-start it and

observe the temperatures at A and B

again after several hours.

If the same

condition exists it could indicate:

B.

A permanent blockage within the boiler

pump tube,

caused by too much heat

applied to the burner (oversized orifice

or heating element) or prolonged operation

of the unit when out-of-level or with

restricted ventilation.

This type of

blockage consists of hard deposits inside

the boiler pump tube. This condition is

not repairable and the cooling unit must

be replaced.

D-9-12

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Comments to this Manuals

Chilombela Terry 12 Mar 2024 | 22:29:54

I want this useful manual