Checking Timer. Maytag MQU1556AEW, AFU2067BW, MQU1554AEW, AQU1525AEW, AFU1505BW, AFU1767BW, MQU2056ARW, AFU1567BW, AFU1705BW, AFU2005BW

Component Testing

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WARNING

To avoid risk electrical shock, personal injury, or death, always disconnect electrical power source to the freezer before attempting to service, unless test procedures require power to be connected. When removing any wiring from terminals they must be replaced on the same terminals.

Ensure all ground wires are connected before certifying unit as repaired and/or operational.

Checking Timer

Unplug line cord from electrical outlet. Remove 1/4 Spin

Tight screws and remove the timer. Disconnect all wires from timer and attach ohmmeter leads to terminals specified in the accompanying chart. If no continuity is indicated, timer has failed and must be replaced. When replacing timer, connect wire leads to timer terminals.

Verify grounding wire is connected.

Ground

wire

Timer mounting

screws

Timer

Ground

wire

Defrost Timer Mounting

To test

Timer motor circuit

Defrost circuit

Compressor circuit

Turn timer knob to

Check between terminals

Leave as is 1 and 3

1

2 st nd

click

click

1 and 2

1 and 4

Turn defrost timer one full turn clockwise to locate start defrost cycle (1st click) and end defrost cycle (2nd click) positions. The 1st and 2nd clicks are only a few degrees of shaft rotation apart. Turn the shaft slowly and stop immediately when the 1st click is heard.

Defrost Heater and Thermostat

No-Defrosting Models

Defrost heater is a radiant heater and will melt all frost that collected during the proceeding 12 hour period when operating properly. Failure to perform this function will eventually cause an ice build-up between the coil fins, blockage in air flow and unsatisfactory refrigeration.

Defrost heater extends across the bottom of freezer coil above the built-in-drain trough. Heater is clamped at both ends to a shield. Shield is attached to coil mounting panel and is slotted to permit free drainage into the drain trough.

Defrost thermostat is located on upper header of freezer coil. Thermostat senses temperature of the header and automatically shuts off the defrost heater when temperature reaches 51°F (11°C).

To test defrost thermostat and defrost heater when the freezer coil temperature is + 15°F (-9°C) or below, use a wattmeter or an ohmmeter and proceed as follows:

1. Disconnect freezer line cord plug from electrical outlet and plug it into wattmeter.

2. Plug-in wattmeter line cord into electrical outlet and manually advance timer to defrost cycle.

3. Wattmeter should indicate approximately 430 watts

(total wattage of timer motor and defrost heater). If indication is 3 watts, defrost heater or defrost thermostat has failed. To isolate failed component, proceed to step 4. However, if indication is 430 watts, timer has (not advancing to defrost) failed and must be replaced.

4. Disconnect freezer line cord plug from wattmeter.

5. Remove freezer coil cover and check defrost heater for continuity. If heater shows continuity, defrost thermostat has failed and must be replaced.

NOTE: Set meter to X1 scale. If reading is approximately 35 ohms, defrost thermostat and defrost heater are operative.

20 16023585 ©2004 Maytag Services