keeping their respective valve ports closed. The ports
open only when electrical power is sent to the solenoid
WATER VALVES.The water valves control
the inflow of hot and cold water during fill operations.
The valves are electrically operated, as shown in figure
5-29. The solenoids are turned off most of the time,
The two water valve solenoids can be operated
individually or at the same time. Activating the "hot"
valve, for instance, fills the washer with hot water.
Energizing the "cold" valve fills the washer with cold
water, and energizing both valves at the same time fills
the washer with warm watera mixture of hot and
The water temperature selector switch determines
the water valves to be operated during any given fill
operation; timer contacts are responsible for
energizing the selected solenoids at the appropriate
A typical water-fill circuit for modern automatic
washers is shown in figure 5-30. The hot- and
cold-water solenoid valves are energized through
several sets of timer contacts and a water temperature
selector switch assembly.
WATER LEVEL SENSING SWITCH.
Washers that do not use a timed-fill interval must have
provisions for sensing the water level and turning off
the water supply whenever a given water level is
reached. This sensor normally takes the form of a
pressure switch that is activated either directly by the
water pressure on the bottom of the laundry tub or
indirectly activated by air pressure in a tube located at
the rear of the washer.
The diagram in figure 5-31 shows the operation of
the indirect, or air pressure, sensing mechanism. The
water level in the tub is always the same as the water
level in the washer. As the water level rises, the air
pressure at the top of the tub increases. A pressure
switch at the top of the tub can be adjusted to close at
various pressure levels, representing different water
levels in the washer.
DOOR INTERLOCK SWITCH.The
interlock switch is a safety feature that completely
shuts down the washer whenever the door or lid is
opened during a spin operation. Opening the door
during any other part of the cycle does not affect the
The diagram in figure 5-32 shows how the door
interlock switch is bypassed by a timer contact. The
timer contact is closed throughout most cycles of the
washer, allowing the lid switch to be opened without
interrupting current flow to the motor circuit. During
every spin operation, however, the timer opens the
bypass switch, letting the lid switch interrupt the
complete circuit to the motor whenever the lid is
opened during that particular operation.
This list of mechanical and electrical components
is not complete as far as the full range of modern
clothes washer models is concerned. This list is
complete, however, in the sense that it describes the
most critical components and those that are unique to
Satisfactory performance of an automatic washing
machine depends on a carefully planned and properly
designed first installation. The place where the
laundry is done should be well lighted and adequately
equipped with convenient electrical outlets. The
plumbing connections must be anchored to the floor to
Figure 5-29.Hot- and cold-water solenoid valve control system.