Refrigerator Troubleshooting Diagram

Archive for the ‘Freezers’ Category

Freezer Thermostats

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Freezers and refrigerators have the same theory of operation. The start relay for the compressor operates the same way as the start relay for a refrigerator. However, the thermostats are somewhat different.

On upright freezers the thermostat is mounted in the upper right-hand corner of the storage compartment in all manual defrost models. The thermostat knob in the manual defrost models is numbered 1 through 6 or coldest and off.

On all other models, remove the right-hand side cold ban trim and filler insulation. Loosen and remove the thermostat thermal element clamp from beneath the refrigerated shelf. Straighten the thermal element and attach a 3-ft length of cord to the end of the thermal element. Use tape. Remove the light shield and thermostat knob. Disconnect the wire leads and remove the thermostat from the mounting bracket. Pull the thermal element out of the insulation.

On the chest models the thermostat is located on the left end of the cabinet near the top of the unit compartment. The dial is marked off, normal, and cold. To stop the compressor during a normal running cycle, pull the service cord from the electrical outlet or turn the thermostat to the off position.

To replace the thermostat, first disconnect the power cord from the electrical outlet, and then remove the knob. Remove the thermostat mounting screws. Pull the thermostat into view in the machine-compartment opening.
Disconnect the wire leads from the thermostat terminals.

Remove the mastic sealer from around the thermal element where it enters the thermal-well trough in the cabinet outer wrapper in the machine compartment.

Before removing the thermal element from the thermal well, wrap a small piece of tape around the thermal element next to the opening of the thermal well.

Remove the thermostat from the machine compartment. Wrap a piece of tape on the new thermostat thermal element at the same location as the tape on the inoperative thermostat. Push the thermal element into the thermal well. To insure the correct length of thermal element in the well for positive contact, the tape on the thermostat thermal element should be at the entrance of the well. Replace the mastic sealer. Connect the wire leads. Install the thermostat mounting screws and knob.

Figures 13-13, 13-14, and 13-15 show three types of thermostats. The thermostats are set at the factory in accordance with the manufacturer’s specifications for cut-in and cutout. No adjustment should be made unless it is absolutely proven that the thermostats are not in accordance with specifications.

If a higher or lower range than is obtainable by the selector knob is desired, adjust the range (altitude)-adjustment screw.

On GE thermostats, the range-adjustment screw is reached through the small hole in the face of the thermostat. See Fig. 13-13. Turn the screw to the left to lower the cutout and cut-in. Turn the screw to the right to raise the cutout and cut-in temperatures. Turning the range screw to the right makes altitude adjustments.

The range-adjustment screw on the Ranco thermostats is located behind a removable cover. See Fig. 13-13. Turn the screw to the left to lower the cutout and cut-in temperatures, and to the right to raise cutout and cut-in temperatures. Turning the range screw to the right makes altitude adjustments.

Cutler-Hammer thermostats have cut-in and cutout temperature adjustment screws. See Fig. 13-15. Turn the screws to the left to raise the cutout and cut-in temperatures and to the right to lower the cut-in and cutout temperatures.

Both cutout and cut-in screws must be adjusted counterclockwise to compensate for altitudes above 1000 ft.

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February 7th, 2011 at 2:15 am

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Freezer Lid

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Most chest-type freezers have flexible lids. Even when the lid is lifted at one corner, it will seal properly on closing under its own weight. The lid’s outer panel is drawn from one piece of steel. The edge is turned back to form a flat flange. This gives strength and furnishes a plane surface for support of the gasket and the lid’s inner panel. Tapping plates for the hinges are welded in place.

The inner lid panel, gasket, handle, lock assembly, and insulation may be seen in Fig. 13-12.

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February 7th, 2011 at 2:06 am

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Freezer Vacuum Release

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Some models have a vacuum release in the bottom edge of the door. This speeds up equalization of the air pressures, permitting successive door openings.

Some models do not incorporate a vacuum-release device. If they have a good airtight gasket seal and the freezer is in operation, the door cannot be opened the second time when two door openings are required in quick succession. This is due to a difference in air pressure between the freezer interior and the room atmosphere. Opening the door the first time results in spillage of cold air from the freezer. This cold air is replaced by warm air. When the door is closed, this warm air is cooled, reducing its specific volume, thus creating a vacuum. Leaving the door closed for about 1 and 11/2 min will allow the air pressure to equalize.

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February 7th, 2011 at 2:02 am

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Freezer Cold-Ban Trim

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Upright models have four-piece sectional cold-ban trim strips that extend around the periphery of the freezer storage compartment. These trim strips are replaceable.

Starting at the lower corners, force the side trims toward the opposite side of the freezer as shown in Fig. 13-6.

Use a small flat screwdriver to release the cold-ban trim from the cabinet U-channel. Then, pull the trims down and out from the overlapping top trim strip. Remove the top and bottom cold trim strips by grasping one end and pulling the trim out of the cabinet U-channel.

Before installing replacement cold-ban trim, be sure the fiberglass filler insulation sections are in place. Install the bottom cold-ban trim. Squeeze one end of the trim and press the front flanges of the trim into the U-channel as shown in Fig. 13-7. Then, use the palm of the hand to press on the rear edge of trim, forcing the lock tabs on the trim over the flange of the freezer liner.

Install the right-hand and the left-hand side cold ban trims. Then install the top cold-ban trim.

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February 7th, 2011 at 1:59 am

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Freezer Wrapped Condenser

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The wrapped condenser incorporates a precooler condenser in series (through an oil cooler) with the main condenser. The condenser, made of 1/4 in. steel tubing, is clamped to the cabinet wrapper. Thermal mastic is applied to each pass for maximum heat dissipation.

A wrapped condenser depends on natural convection of room air for dissipation of heat. Restricted air circulation around the cabinet will cause high operating temperatures and reduced capacity. The wrapped condenser reduces the possibility of moisture condensing on the cabinet shell during extremely humid weather. It also eliminates the need for periodic cleaning of the condenser. Figure 13-5 shows the condenser layout on an upright freezer.

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February 7th, 2011 at 1:50 am

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Installing Freezer

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It may be necessary to remove the freezer door for passage through narrow doors. With each freezer there is an instruction sheet explaining the step-by-step procedure for door removal. Screw-type levelers are used to adjust the level of the freezer. Upright freezer models use a screw-type leveler that can be moved up and down by turning to the left or right. See Fig. 13-4.

The cabinet must be level side-to-side with a very slight tilt toward the rear. This will aid in obtaining a tight door gasket seal. If the cabinet is tilted toward the front, the weight of the door, plus the door food load, will result in poor gasket seal.

Do not locate the freezer adjacent to a stove or other heat source. Avoid an area that is exposed to direct sunlight for long periods.

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February 7th, 2011 at 1:39 am

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Types Of Freezers

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There are two types of domestic freezers—the upright freezer and the chest-type freezer. The essential parts of the upright freezer are shown in Fig. 13-1.

Notice that the evaporator coils are built into the shelves as part of that unit. This means the shelves are not adjustable. Notice that the condenser coils (17) in Fig. 13-1 are welded to the outside of the cabinet. This prevents sweating and aids the dissipation of heat over a large surface. The primary convenience of this type of freezer is that the frozen food is visible, easily arranged, and easily removed.

The chest-type freezer provides a different storage arrangement. See Fig. 13-2. In some instances, the condenser coils are mounted on the back of the chest-type freezer.

The electrical diagram for a chest-type freezer is shown in Fig. 13-3. Note that the thermostat controls the on-off operation of the compressor. The light switch completes the circuit from one side of the power cord to the other through the light. Some models have a mercury switch that operates when the lid is up. This type of freezer does not have automatic defrost. Defrosting must be done manually.

Written by sam

February 7th, 2011 at 1:34 am