Water-Level Switch.- The water-level switch, normally actuated by pressure, controls the amount of water that enters the tub. The switch has an adjustment screw to set the level of the water. The tighter the screw, the more pressure is required to operate the switch, and the higher the water level required The water-level switch has two sets of contacts, one normally opened and the other normally closed. As the correct water level is reached, the switch opens one set of contacts, de-energizing the water fill valve. The other set of contacts closes and completes a circuit to the timer, allowing the timer to operate and start the next cycle. The timer will not operate during the fill cycle.

Safety Switches.- Most washers have at least two safety switches. One is an off-balance switchthat opens a circuit to the motor if the clothes shift to one side. Moving the tub to the center and rearranging the clothes will close the switch, allowing the washer to operate. This switch prevents damage to the machine from the vibration of operating with an unbalanced load The other safety switch is located near the door of the machine. Opening the door will stop the machine from operating. Some machines do not have this switch but have a locking solenoid. When the machine goes into the spin cycle, the solenoid latches the door to keep it from being opened during the spin cycle.

ELECTRICAL OPERATION.- Let's look at the electrical operation of a washer. With the plug connected to the outlet, the timer is turned to WASH and the dial is pushed in or pulled out, depending on the type of switch. The operational cycle continues as follows:

1. From the ON/ OFF switch, power flows through the temperature control switch and the water-level switch to the inlet solenoid valve. That energizes the inlet valve, allowing the tub to fill.

2. The timer motor is de-energized during the fill cycle because of the open set of contacts in the water-level control switch.

3. Once the water reaches the proper level, one set of contacts opens to shut off the fill solenoid. The other contacts close, sending power to the timer and, at the same time, energizing the motor for the wash cycle.

4. At the end of the wash cycle, power is fed from the timer to the solenoid on the pump, engaging the pump and removing water from the tub.

5. Once the tub is empty, the solenoid for the spin cycle is energized. Its power is fed through the door switch to the solenoid so that, if the door is opened, the machine shuts down

6. During the spin cycle, the water pump is running, and the tub is operating at high speed The timer has provided a bypass circuit around the now open set of contacts in the water-level control switch

7. Once the cycle is completed, the pump, the high-speed solenoid, and the motor are de-energized because there is no water in the tub.

8. The water-level switch closes, energizing the inlet water solenoid to fill the tub for the rinse cycle.

Figure 7-3.- Typical wiring diagram of a washing machine.

9. The rinse cycle is completed in the same manner repair. When troubleshooting a washer, you need to as the wash cycle, and after this cycle, the timer shuts down, completing the operation.

have the wiring diagram for that particular washer. Normally, it is pasted to the back panel. Try starting the machine and observing its operation. Run the machine