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13.2
Evaporator Replacement
The evaporator is located in the FC compartment mounted on the back wall on its own carrier, with
a grill covering a fan motor, which is housed in the front cover.
Having determined that the evaporator needs replacing:
1.
Disconnect the refrigerator from the power supply.
2.
Recover the refrigerant.
3.
Remove the FC drawer (refer to Section 11.4.10).
4.
Remove the evaporator coil cover.
5.
Clean both the suction and capillary pipes with emery cloth.
6.
With a tube cutter, cut the suction pipe as close as possible to the induction brazed joint
(cutting the suction capillary side of the joint).
7.
With a file or knife, cut the capillary where it enters the transition joint on the evaporator.
8.
With the element wiring disconnected, the evaporator can be removed.
9.
Take the replacement evaporator and fit it to the carrier, fitting the defrost element assembly
and the 2 pieces of heat shrink sleeving onto the pipes.
10. Align the evaporator and joints ready to be soldered into position.
11. Lay the product on its back.
12. Place a protective covering over the back of the liner to protect it should solder drop onto it
while the joint connections are being made.
13. Fit the suction and capillary lines together, with a protective heat shrink sleeving placed on the
pipe first away from the heated area. Care must be taken when brazing near the plastic liner.
14. The same applies for the capillary, applying more heat to the transition joint as it is heavier in
material than the capillary.
15. Pressure test both joints.
16. Fit heat shrink sleeving over the joints and heat, having placed damp rags around the area of
the ABS liner as heating the heat shrink can cause the liner to be overheated. It is also
important to keep the thermal fuse in the element circuit away from the heat gun, as heat from
the heat gun can cause the thermal fuse to go open circuit.
13.3
Refilling a Void In Foam Insulation
When 50ml of each foam component is mixed together, sufficient insulation will be formed to fill a
space of approximately 25cm x 25cm x 50mm (10" x 10" x 2") deep (3 litre volume). "Freefoam"
means that the space being filled is not fully enclosed.
The foam is handled as follows:
1.
Roughly determine the volume of the void to be foamed and then determine how much
activator and resin is required. Do a test run mixing a 1/4-cup of each to estimate your
requirement (on waste cardboard).
2.
Measure equal quantities of activator and resin into a large wax cup or similar and mix briskly
with a wooden spatula for 10-15 seconds.
indicates that mixing is complete.
3.
Pour the mixture into the void and allow to foam. More can be added if necessary.
4.
When the foam is firm, remove excess with a sharp knife, apply film of wax and vapour seal to
the triple fold, refit the back panel, making sure the panel is perfectly vapour sealed.
5.
DO NOT OPERATE THE APPLIANCE FOR AT LEAST FOUR HOURS AFTER FOAMING.
6.
The foam solvent used for cleaning while the foam is still in a liquid state is methylated spirits.
CAUTION
1.
Avoid splashing the mixture onto the cabinet. Once set, foam is almost impossible to remove.
2.
When clearing a pocket for foaming, it is recommended to leave a layer of old foam against
the ABS plastic liner for support and to prevent the pressure of the foam causing a bulge on
the PC inside surface.
13.3.1
Polyurethane Foam
The insulation material being used in refrigerator and home freezer cabinets is polyurethane foam.
Polyurethane foam is a two-part mix, consisting of a pre-mix and an isocyanide. The pre-mix
contains: polyol, catalyst, silicone surfactant, water and fluorocarbon-II. The isocyanate is 4,4 1
The mixture will start to feel warm, and this
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