Fix-it-Yourself--Major Appliances: REFRIGERATORS (part 3)

TESTING AND REPLACING THE DEFROST HEATER

1 Testing the defrost heater. The defrost heater element may be enclosed within a glass tube and hidden beneath a metal reflector shield between the evaporator coils (far left). Alternatively, it may be wrapped in aluminum foil (near left, top), or it may be an exposed metal rod (near left, bottom). All elements are tested the same way. Unplug the refrigerator and remove the evaporator cover, insulation and heat shield (25). Pull the wire connectors from the terminals at each end of the defrost heater. Set a multitester at RX1 and attach a probe to each terminal. The meter should show medium to high resistance. If not, replace the element. If the element is good, test the defrost limit switch (27).

2 Removing the defrost heater. Unhook the element’s reflector shield from the clips at each end, and carefully lift the element out of its brackets. This will expose the opening to the drain tube. Before installing a new element, clean the drain tube by using an oven baster to force a solution of hot water and baking soda or bleach into the opening (inset).

3 Installing a new defrost heater. Don’t touch the glass surface of the new heater element; oils from your skin will cause hot spots. If you do touch the element, wipe it thoroughly with a paper towel. Plug the new element in the same position as the old one and replace all clips or fasteners. Next, reconnect the push-on connectors to the element terminals and snap in the reflector shield, if any. If you are not testing the defrost limit switch (27), reinstall the evaporator cover, insulation and heat shield (25). Take special care to reconnect the ground wire.

TESTING AND REPLACING THE DEFROST LIMIT SWITCH

1 Baring the defrost Limit switch wires. The defrost limit switch, located next to the evaporator, turns off the defrost heater when all the frost has melted during the defrost cycle. To reach it, unplug the refrigerator and remove the evaporator cover, insulation, and heat shield (25). If the defrost limit switch has push-on connectors, disconnect them. On most refrigerators, however, the switch is permanently wired. To test such a switch, you must bare the two switch wires. Taking care not to cut or fray the copper strands inside, use a sharp utility knife to remove a small patch of the plastic insulation around each wire (above).

2 Testing the defrost Limit switch. The switch should have complete continuity when it’s cold, and no continuity when it’s warm. To test the switch, place a plastic bag full of dry ice on it for 20 minutes. Remove the ice and touch a multitester probe to each of the two exposed wires (or to each switch terminal). The tester should show continuity. Then warm the switch using a hair dryer set on LOW. The multitester needle should swing downscale to show resistance. If the switch fails either test, replace it. If the switch is good, tape the exposed wires (step 3).

3 Taping wires or replacing the defrost limit switch. If the switch is good, reseal the bared wires with electrical tape, covering the cut patches and one inch on each side (above, left). If the defrost limit switch has terminals, reconnect the push-on connectors. If the switch is faulty, cut the wires at the bared spots. Splice them to the wires of a new switch (136) using wire caps (above, right) or crimp connectors waterproofed with a dab of silicone sealant. Snap the new switch into place. Reinstall the evaporator cover (25). Take special care to reconnect the ground wire.

SERVICING THE CONDENSER FAN

1 Inspecting the condenser fan. On refrigerators with the con denser at floor level, the condenser fan circulates cool air over the condenser coils. Unplug the refrigerator and pull it away from the wall. Clean the fan blade, and turn it to see if the blade rotates freely (above). If the motor binds, test it (step 2). If the fan blade is damaged, unscrew the nut that holds it to the motor shaft and pull it off. Install a new fan blade, replacing any washers, and tighten the nut.

2 Testing the condenser fan motor. Disconnect the wires to the fan motor. Set a multitester at RX1O and touch one probe to each terminal (above, left). The multitester needle should move to the medium range of the scale, showing partial resistance; a low reading means the motor is faulty. Next set the multitester at RX1 000 and touch one probe to the motor terminals and the other to any unpainted metal part of the refrigerator (above, right). If the multitester needle moves, the motor is grounded and should be replaced.

3 Removing the motor. Unscrew the brackets that hold the fan motor to its housing; if necessary, unscrew the mounting plate from the motor. Slide the motor backward out of the housing.

4 Replacing the motor. Remove the fan blade from the old motor and attach it to the new motor (step 1), replacing any washers. Install the new motor in its housing by screwing the brackets in place. Reattach the wires to the motor terminals and reconnect the green ground wire.

SERVICING THE COMPRESSOR

1 Replacing the compressor mountings. Unplug the refrigerator and pull it away from the wall. If it has an access panel, remove it. Using an adjustable wrench or socket wrench, unscrew the nut securing one foot of the compressor (above, left). Jack up the compressor foot with a pry bar, just far enough to pull out the shock absorber mounting from beneath it (above, right). Slip a new mounting in place and lower the compressor foot. Replace the washer and tighten the nut. Repeat for each mounting; don’t remove more than one at a time.

2 Removing the compressor terminal cover. The compressor is part of the closed refrigeration system and should be replaced only by a professional service technician. You can, however, test the compressor and certain components. Unplug the refrigerator, pull it away from the wall and remove the rear access panel, if any. A small box mounted on the compressor cover protects the relay, overload protector and capacitor, if any. Release the wire retaining clip that holds the cover in place (above) and slip off the cover and the clip. Caution: If the compressor has a capacitor, discharge it before proceeding (111).

3 Removing and testing the compressor relay. Pull the relay straight off the compressor without twisting it (above). If the relay has an external wire coil, hold the relay so that the word TOP is up. Set a multitester at RX1 and place the probes on the terminals marked S and M. The multitester needle should not move. Next remove the probe from M and place it on the side terminal marked L. Once again, the needle should not move. Finally, remove the probe from S and place it on M. The needle should sweep across the scale, showing full continuity.

Now turn the relay upside down (you’ll hear a click as the magnetic switch inside the relay engages) and perform the same tests (above, right). You should get the opposite results: continuity between terminals S and M and between S and L; no continuity between M and L. If the relay fails any of these tests, replace it: Push the new relay onto the compressor terminals and replace the terminal cover. If the relay passes these tests, test the overload protector.

If the relay has no wire coil, hold the relay so that the word TOP is up. (Otherwise, hold it either way). Set a multitester at RX1 and touch a probe to each terminal. The needle should sweep to the middle of the scale. A high or low reading means the relay has failed; replace it as above. If the relay passes the tests, test the overload protector(step 4).

4 Removing the overload protector. Using a screwdriver, gently pry open the circular spring clip that secures the overload protector to the compressor and snap out the protector, as shown. Pull the two wire connectors off their terminals.

5 Testing the overload protector. Set a multitester at RX1 and touch a probe to each overload protector terminal. The multi- tester needle should sweep across the scale, showing full continuity. If the overload protector passes this test, test the compressor (step 6). If not, replace the overload protector. Reattach the push-on connectors to the new overload protector, clip it in place on the compressor and replace the terminal cover.

6 Testing the compressor. With a multitester set at RX1, test each of the three terminal pins against each of the other two (above, left). Each pair should show continuity. Then, with the multitester set at RX1 000, place one probe against the metal housing of the compressor (above, right); if necessary, scrape off a little paint to ensure contact with bare metal. Place the other probe on each of the three compressor terminals in turn. If any of the three terminals shows continuity with the housing, the compressor is grounded. If the compressor fails either test, call for service. If it passes the tests, reinstall the overload protector, relay, terminal cover and rear panel, if any.

ICEMAKERS

Mounting plate: Motor and water inlet valve switch are attached to back of plate.

Thermostat: Senses water temperature in mold and activates ejector when ice cubes reach 18°F.

ACCESS TO THE ICEMAKER

1 Disconnecting and opening the icemaker. Unplug the refrigerator and take out the ice bin. Remove the screw from the icemaker’s bottom bracket and, supporting the icemaker with one hand, remove the top screws and clips (left, top). Lower the icemaker and unplug it from the refrigerator wall (left, bottom). To remove the cover, insert the edge of a coin into one of the slots at the bottom and twist it (above, right).

Plug; Water inlet tube

2 Inspecting the gear wheel. Turned by the small motor gear, the gear wheel controls the ice cube ejector and the switches. Before removing the mounting plate (step 3), inspect the gear wheel for damage. To replace a damaged wheel, remove the screw at its center and pull the gear off its cam; save the washer. Place a new gear wheel on the cam and replace the washer and screw.

3 Removing the mounting plate. If the icemaker doesn’t have a large gear wheel outside the mounting plate (previous step), don’t remove the plate; call for service. If there is a gear wheel, remove the screws around the edges of the mounting plate (inset) and pull it away from the icemaker. You now have access to the motor, switches, thermostat and shutoff arm (above).

REPLACING THE ICEMAKER SHUTOFF ARM

1 Releasing the spring. When the shutoff arm is pushed up by accumulating ice, it shifts a lever that turns off the icemaker. To inspect the arm and lever, unplug the refrigerator, take out the icemaker (32) and remove the mounting plate. Check that the spring is engaged on the shutoff arm (above), and that the arm fits into the lever slot. To remove the arm, first disengage the spring carefully.

2 Removing the shutoff arm. Disengage the arm from the lever. Push the arm forward, turning it when necessary to work it out through its hole in the housing (above). To install a new shutoff arm, slide it in through the front of the housing. Engage the arm in the lever and replace the spring. Replace the mounting plate and cover, and reinstall the icemaker.

TESTING ICEMAKER SWITCHES

Testing the ON/OFF switch and the holding switch. Although they are identical, these switches perform different functions. The ON/OFF switch turns off the icemaker when the shutoff arm is raised, and the holding switch keeps the power going while the ejector pushes out the ice cubes. To reach the switches, unplug the refrigerator, take out the icemaker (32) and remove the mounting plate (33). The ON/OFF switch is located behind the shutoff lever (above, left); the holding switch is mounted next to the motor (above, center). Label and disconnect the wires, and test both switches the same way: Clip one probe of a multitester set at RX1—or a continuity tester—to the common terminal on the side of the switch. Touch the other probe to each of the other two terminals in turn. With the switch button out (above, right), the tester should show continuity through one terminal and resistance through the other. Press the button in; the results should reverse. If not, replace the switch. Screw a new switch in place, reconnect the wires, and reassemble and reinstall the icemaker.

Testing the water inlet valve switch. This switch turns on the water inlet valve, allowing it to meter water into the ice mold. To test the switch, unplug the refrigerator, take out the icemaker (32) and remove the mounting plate (33). Unscrew the switch from the plate (above, left); save the card-like insulator underneath it. Disconnect and label the wires. With a multitester set at RX1—or a continuity tester—touch one probe to each switch terminal (above, right). With the button out, the tester should show continuity; with the button in, resistance. If the switch fails the test, replace it. Position the insulator on the mounting plate with its slanted edge toward the center. Put the switch on top of it and screw it in place. Reconnect the wires, and reassemble and reinstall the icemaker.

TESTING THE ICEMAKER MOTOR AND THERMOSTAT

1 Testing the motor. Unplug the refrigerator, take out the icemaker (32) and remove the mounting plate (33). Disconnect the motor wires: One wire has two connectors that pull off the switch terminals; the other is connected with a wire cap. Set a multitester at RX10 and touch a probe to each wire (above). The tester should indicate 400 to 600 ohms of resistance. If not, unscrew the motor from the mounting plate (inset) and install a new motor, making sure the small gear on the motor meshes with the large gear on the mounting plate. Reconnect the wires, and reassemble and reinstall the icemaker. If the motor tests OK, next test the thermostat.

2 Testing the thermostat. Unscrew the clamp (above) to free the thermostat. Label and disconnect the wires. If the thermostat has three wires (inset), clip one probe of a multitester set at RX1—or a continuity tester—to the shorter of the two wires with connectors. Touch the other probe to the other wires in turn. A warm thermostat should show continuity through one wire and resistance through the other. Put the thermostat in a freezer at 10°F or less for 15 minutes and test again; the results should reverse. (If the thermo stat has two wires, they should show resistance when warm and continuity when cold.) To install a new thermostat, put a dab of factory- specified metallic putty on its back and stick it in place. Screw on the clamp, reconnect the wires, and reassemble and reinstall the icemaker.

SERVICING THE ICEMAKER WATER INLET VALVE

Inspecting and testing the water inlet valve. Unplug the refrigerator and turn off the water supply to the icemaker (usually at a valve under the sink). Pull the refrigerator out from the wall. To remove the water inlet valve, unscrew its bracket from the back of the refrigerator and disconnect the tube sleeves from the valve ports (above, left). Keep a pan handy to catch dripping water. Disconnect the valve terminal plug and the ground wire. Use a screwdriver to pry out the filter from the inlet port (above, center) and rinse it in clear water. To test the water inlet valve solenoid, set a multitester at R x 10 and touch a probe to each terminal (above, right). The tester should show 200 to 500 ohms of resistance; if not, replace the water inlet valve. To install a new valve, reconnect the terminal plug and ground wire, screw the bracket on the refrigerator and reconnect the tube sleeves to the valve ports. Push the refrigerator back in position, plug it in and turn on the water. After installing a new water inlet valve, discard the first two or three batches of ice.