Back to main page Atlanta Appliances repair, Inc.
Electric Appliance and Air Conditioner Parts
Servicing a highly complex electromechanical appliance or room air conditioner is not
as hard as might be expected. Just keep in mind that an appliance or air conditioner is
simply a collection of parts, located inside a cabinet, coordinated to perform a specific
function (Figures 10-1a, 10-1b, 10-1c, 10-1d, and Figure 9-4). Before servicing an appliance or
air conditioner, you must know what these parts are and how they function.
The switch is a mechanical device used for directing and controlling the flow of current in
a circuit. Simply put, the switch can be used for turning a component on or off (Figure 10-2).
Internally, the switch has a set of contacts that close, allowing the current to pass; when
opened, current is unable to flow through it. Built into the switch, a linkage mechanism
actuates these contacts inside of the closed housing (Figure 10-3).
Switches come in a wide range of sizes and shapes, and can be used in many different
types of applications (Figure 10-4). The voltage and amperage rating is marked on the
switch or on the mounting bracket for the type of service the individual switch was
designed to do. The switch housing is usually marked with the terminal identification
numbers that correspond to the wiring diagram. These identify the contacts by number:
normally open (NO) contacts, normally closed (NC) contacts, or common (COM) contacts.
Internally, the switch can house many contact points for controlling more than one circuit.
When a switch failure is suspected, remember that there are only three problems that
can happen to a switch:
•The contacts of the switch might not make contact. This is known as an open switch.
•The switch’s contacts might not open, causing a shorted switch.
•The mechanism that actuates the contacts might fail. This is a defective switch.
When these problems arise, the switches are not repairable, and they should be replaced
with a duplicate of the original.
Bake and broil
Oven and panel
Top burner elements
Infinite (top element)
Model and serial
Lower spray arm
Rinse agent dispenser
Thepressure switch is a specialty switch, with a similar operation to those mentioned
previously, but with one important exception: The pressure switch is actuated by a diaphragm
that is responsive to pressure changes (Figure 10-5). This switch can be found in washing
machines and in dishwashers, and it operates as a water level control. Other uses include
furnaces, gas heaters, computers, vending machines, sump pumps, and other low-pressure
applications. The pressure switch is not serviceable, and should be replaced with a duplicate
of the original.
FIGURE 10-2The wiring diagram illustrates a switch in the closed position. If the switch is closed, the
light and motor are on. If the switch is open, the light and motor are off.
FIGURE 10-3The exploded view of a switch.
Mounting hole Silver switch
Thethermostat operates a switch. It is actuated by a change in temperature. The two most
common heat-sensing methods used in appliances and air conditioners are the bimetal and
the expansion thermostats (Figure 10-6).
Thebimetal thermostat (Figure 10-7) consists of two dissimilar metals combined together.
Any change in temperature will cause it to deflect, actuating the switch contacts. When the
bimetal cools, the reverse action takes place.
FIGURE 10-4This is a sample of the many types of switches used in major appliances.
Theexpansion (temperature control) thermostat (Figure 10-8) uses a liquid in a tube that is
attached to bellows. The liquid converts to a gas when heated and travels up the tube to the
bellows. This causes the bellows to expand, thus actuating the switch contacts. When the
gas cools, the reverse action occurs.
Thermostats are used in applications as diverse as gas and electric ranges, automatic
dryers, room air conditioners, irons, waterbeds, spas, and in heating and refrigeration units.
Although the timer is the most complex component in the appliance, don’t assume that it is
the malfunctioning part. Check all of the other components associated with the symptoms
as described by the customer.
Construction of a
FIGURE 10-6Bimetal and expansion thermostats.
Electromechanicaltimers are utilized for controlling performance in automatic washers,
automatic dryers, and dishwashers. Most of these timers are not serviceable and should be
replaced with a duplicate of the original.
The timer assembly is driven by a synchronous motor in incremental advances. It controls
and sequences the numerous steps and functions involved in each cycle of an appliance
(Figure 10-9). The timer directs the on and off times of the components in an electrical circuit.
It consists of three components assembled into one unit: the motor, the escapement, and the
A solenoid is not a serviceable part and
should be replaced with a duplicate of the
original. These devices are manufactured in a
variety of designs for various load force and
operational requirements. Solenoids are found in
automatic washers and dryers, gas and electric
ranges, automatic dishwashers, refrigerators,
freezers, automatic ice machines, and in heating
and air conditioning units.
a water valve.
The solenoid coil and
plunger. When the coil
is activated, the
plunger will be drawn
to the center of the
The water inlet valve controls the flow of water into an appliance, and is solenoid-operated
(Figure 10-15). When it is energized, water in the supply line will pass through the valve
body and into the appliance. Some of the different types of water inlet valves that are used
on appliances include:
•Single water inlet valve (Figure 10-16) Used on dishwashers, ice makers,
refrigerators, undercounter appliances and ice machines.
•Dual water inlet valve (Figure 10-17) Used on washing machines, refrigerators,
and ice makers. Some dishwasher models also use dual water inlet valves. The inlet
side of the valve has a fine mesh screen to prevent foreign matter from entering the
valve. Some water valves also have a “water hammer” suppression feature built
Drain valves (Figure 10-18) are used on some dishwasher and washing machine models
to control the drainage of the water in the tub and its expulsion into the sewage system of
The water valve should not be serviced. Replace it with a duplicate of the original.
FIGURE 10-16The single water valves are just some of the different types available that are used in
FIGURE 10-17These dual water valves are designed for dual water inlet connections.
The two major assemblies that form an electric motor are the rotor and the stator (Figure 10-19).
The rotor is made up of the shaft, rotor core, and (usually) a fan. The stator is formed from
steel laminations, stacked and fastened together so that the notches form a continuous
lengthwise slot on the inside diameter. Insulation is placed so as to line the slots; and then
coils, wound with many turns of wire, are inserted into the slots to form a circuit. The wound
stator laminations are pressed into, or otherwise assembled within, a cylindrical steel frame to
form the stator (Figure 10-20). The end bells, or covers, are then placed on each end of the
motor. One important function of the end bells is to center the rotor or armature accurately
within the stator to maintain a constant air gap between the stationary and moving cores
(Figures 10-19 and 10-21).
These coils of wire are wound in a variety of designs, depending upon the electrical
makeup of the motor. They provide two or more paths for current to flow through the stator
windings. When the coils have two centers, they form a two-pole motor; when they have
FIGURE 10-18The drain water valves.
FIGURE 10-19The stator and rotor.
four centers, they form a four-pole motor. In short, the number of coil centers determines
the number of poles that a motor has (Figure 10-22).
Thermal protection in a motor is provided by a temperature-sensitive element, which
activates a switch. This switch will stop the motor if it reaches the pre-set temperature limit.
The thermal protector in a motor is a non-replaceable part, and the motor will have to be
replaced as a complete component. There are two types of thermal protection switches:
•Automatic reset It automatically resets the switch when the temperature has been
•Manual reset It has a small reset button on the motor on the opposite end from
Stator and rotor
End bells position the
motor shaft in the
center of the stator.
Several types of motors that are used for different types of applications include the
•Synchronous motors are permanent magnet-timing motors, often used in automatic
ice cube makers, water softeners, and humidifiers. In addition, they are integral to
timers for automatic washers, automatic dryers, and dishwashers.
•Shaded pole motors are used as continuous duty motors, with limited or adjustable
speeds. They are used for small fans and clocks.
•Split phase motors are used as continuous duty motors, with fixed speeds. They are
often used in automatic washer and dryer drive motors.
•Capacitor start motors are similar to the split-phase motors, and they are used in
hard-to-start applications, such as compressors and pumps.
•Permanent split capacitor motors are used in a variety of direct-drive air-moving
applications—for example, air conditioner fans.
•Three-phase motors are used in industrial or large commercial applications where
three-phase power is available.
•Multispeed, split-phase motors are used in fans, automatic dryers, automatic washers,
and many other appliances.
•Variable-speed, reversible, three-phase induction DC motor, used in some domestic
•Direct current (DC) motors, used in refrigerators, washers, dryers, ranges,
Figure 10-23 illustrates some of these motors. Appliance motors are not repairable, and
they should be replaced with a duplicate of the original.
The compressor is an electric motor that drives a mechanical compression pump designed
to compress the refrigerant vapors and to circulate the refrigerant within a sealed system.
Domestic refrigeration and room air conditioners use a hermetic compressor. The electric
FIGURE 10-23Motors are available in different sizes and shapes.
motor and mechanical compression pump are sealed within the same housing (Figure 9-7),
and it is a non-serviceable part. If the compressor fails, it must be replaced with a duplicate
of the original by a certified technician. Two types of compressors are used in domestic
refrigeration and room air conditioners: reciprocating and rotary. For more information on
compressor construction, visit the following compressor manufacturer’s websites:
A capacitor is a device that stores electricity to provide an electrical boost for motor starting
(Figure 10-24). Most high-torque motors need a capacitor connected in series with the start
winding circuit to produce the desired rotation under a heavy starting load.
There are two types of capacitors:
•Start capacitor This type of capacitor is usually connected to the circuit between
the start relay and the start winding terminal of the motor. Start capacitors are used
for intermittent (on and off) operation.
•Run capacitor The run capacitor is also in the start winding circuit, but it stays in
operation while the motor is running (continuous operation). The purpose of the
run capacitor is to improve motor efficiency during operation.
Capacitors are rated by voltage and by their capacitance value in microfarads (μF). This
rating is stamped on the side of the capacitor. A capacitor must be accurately sized to the
motor and the motor load. Always replace a capacitor with one having the same voltage
rating and the same (or up to 10 percent greater) microfarad rating. On larger capacitors,
the rating is stamped on the side. Also, watch out for the decimal point on some capacitors.
FIGURE 10-24(a) The capacitor is rated by voltage and by capacitance (in microfarads). (b) This builtin
disconnect device is also known as a fail-safe.
Normal Fail-safe mode
The rating might read .50μF instead of 50 μF. Small capacitors in electronic circuits are rated
by numbering or are color-coded.
Capacitors are used in electrical circuits to perform the following:
•An electrical voltage boost in a circuit
•Control timing in a computerized circuit
•Reduce voltage disruptions and allow voltage to maintain a constant flow
•Block the flow of direct current when fully charged and allow alternating current to
pass in a circuit
Both run and start capacitors can be tested by means of an ohmmeter or a capacitor tester.
Testing a Capacitor
Before testing a capacitor, disconnect the electricity. This can be done by pulling the plug from
the electrical outlet. Be sure that you only remove the plug for the product you are working
on. Or, you can disconnect the electricity at the fuse panel or at the circuit breaker panel.
Some appliance or air conditioner models have the capacitor mounted on the motor,
and some are mounted to the cabinet interior in the rear of the machine. Access might be
achieved through the front or rear panel, depending on which model you are working on.
Do not touch the capacitor until it’s discharged.
WARNING A capacitor will hold a charge indefinitely, even when it is not currently in use.
A charged capacitor is extremely dangerous. Discharge all capacitors immediately any time that
work is being conducted in their vicinity. Redischarge after repowering the equipment if further
work must be done.
Many capacitors are internally fused. If you are not sure, you can use a 20,000-ohm,
2-watt resistor to discharge the capacitor. Do not use a screwdriver to short out the capacitor.
By doing so, you will blow out the fuse in the capacitor and the capacitor will not work.
Safely use an insulated pair of pliers to remove the wires from the capacitor, and place the
resistor across the capacitor terminals. Set the ohmmeter on the highest scale, and place one
probe on one terminal and the other probe on the other terminal (Figure 10-25). Observe the
Placing ohmmeter test
leads on the capacitor
meter action. While the capacitor is charging, the ohmmeter will read nearly zero ohms for a
short period of time. Then the ohmmeter reading will slowly begin to return toward infinity.
If the ohmmeter reading deflects to zero and does not return to infinity, the capacitor is
shorted and should be replaced. If the ohmmeter reading remains at infinity and does not
dip toward zero, the capacitor is open and should be replaced.
When using a capacitor analyzer to test capacitors, it will show whether the capacitor is
“open” or “shorted.” It will tell whether the capacitor is within its microfarads rating, and
it will show whether the capacitor is operating at the proper power-factor percentage. The
instrument will automatically discharge the capacitor when the test switch is released.
Most heating elements are made with a nickel-chromium wire, having both tensile strength
and high resistance to current flow. The resistance and voltage can be measured with a
multimeter to verify if the element is functioning properly. Heating elements are available
in many sizes and shapes (Figure 10-26). They are used for
•Heating air for drying clothes
•Heating water to wash clothes, dishes, etc.
Heating elements are not repairable, and they should be replaced with a duplicate of the
FIGURE 10-26Heating elements.
The mechanical linkages are those devices (connecting rods, gears, cams, belts, levers, pulleys,
etc.) that are used on appliances and air conditioners in order to transfer mechanical energy
from one point to another. Figure 10-27, the automatic ice maker, is an excellent example of
this. Some other examples are:
•In the automatic dryer, the motor is turning a pulley, which moves a belt, which
turns the drum.
•In the automatic washing machine, the motor turns a pulley, which moves the belt,
which turns the transmission gears, which performs the agitation or spin cycle.
•In the automatic ice maker, the timer gear turns the drive gear, which moves the
cam, which actuates the switches and rotates the ice ejector.
Brass drive gear
Motor, ice maker drive
weigh switch shaft
ice level control Gear
ice maker drive
FIGURE 10-27The ice maker is a perfect example of mechanical linkages in use.
The wiring, which connects the different components in an appliance or air conditioner, is
the highway that allows current to flow from point A to point B. Copper and aluminum are
the most common types of wires that are used in appliances. They are available as solid
or stranded. Wires are enclosed in an insulating sleeve, which might be rubber, cotton, or
one of the many plastics. Wires are joined together or to the components by:
•Solderless wire connectors
•Solderless wire terminal connectors
•Solderless multiple-pin plug connectors
Never join copper and aluminum wires together, because the two dissimilar metals will
corrode and interrupt the flow of current. The standard wire-gauge sizes for copper wire are
listed in Table 10-1. As the gauge size increases from 1 to 20, the diameter decreases and the
amperage capacity (ampacity) will decrease also (see Table 10-2).
How to Strip, Splice, Solder, and Install Solderless and Terminal
Connectors, and How to Use Wire Nuts on Wires
To strip the insulation off the wire, there are certain steps you need to follow. First, you
must have a good wire stripper (Figure 10-28). Now, place the wire in the proper sized slot
in the wire stripper and work the stripper back and forth until a cut is made in the entire
insulation. Do not damage any of the strands in a stranded wire or put a knick in a solid
wire; this will cause a weakness in the wire that may cause a break in the circuit in the nottoo-
distant future. To remove the insulation, hold the wire tight with one hand and use the
other hand to gently move the insulation back and forth until the cut breaks clean and the
unwanted insulation can be pulled off the wire (Figure 10-29). Next, taper the insulation
with a knife to increase the wire’s flexibility, because a straight cut in the insulation will
create a force that can cause a wire to break prematurely (Figure 10-30). Figures 10-31 and
10-32 illustrate the different methods of splicing single and stranded wires together.
To connect wires to screw terminals, the wire being attached at a screw terminal should
be connected so that the loop lies in the direction the screw turns (Figure 10-33). The wire
should loop the screw a little less than one full turn, but excessive loops around the screw
terminal are not recommended, as this could cause wire damage.
Here is a good guideline that you should practice for soldering wire splices (Figures 10-34,
10-35, and 10-36). First, the wire being soldered together should be bright and clean at the
point of connection. The connection point should be tight so that the solder can flow
between the joint and solidify without any wire movement. When soldering wires together,
the wires should be coated with an electric soldering paste of flux, and soldered so that the
solder melts and flows into every crevice of the spliced joint. After the soldered joint cools,
the entire splice area should be covered with a waterproof plastic tape or heat-shrink
covering to protect the joint from shorting out against the cabinet of the product.
When you have to attach a
solderless connector or wiring
terminal to a wire, you should
follow these guidelines. Solderless
connectors should be used
according to their color codes, and
a connector for a smaller-gauge
wire should never be used on a
heavier-gauge wire. The wire
connector might burn off the wire
and break the circuit. A screw-on
wire connector (also known as a
wire nut) works well on pigtail
splices (Figure 10-37).
When installing a crimp-on
connector (Figure 10-38), there
should not be a gap between the
insulation and the terminal
connector, and if there is a gap, a
plastic sleeve should be added to
cover the bare wire, or reinstall a
new connector if needed. Always
prevent wires from shorting out and
breaking the circuit, causing you to
have to return to the service call.
Circuit Protection Devices
Circuit protection devices are
important for appliances and air
conditioners. These devices will
protect the electrical circuits and
components from damage from too
much current flow. Each fuse
(Table 10-3) or circuit breaker
(Figures 10-39, 10-40, and 10-41)
must be rated for voltage and
current. Never replace a fuse or
circuit breaker with one that is not
correctly rated for the product.
Fuses and circuit breakers must be
able to do the following:
•Sense a short in the circuit
•Sense an overloaded circuit
(too much current)
Back to main page Atlanta Appliances repair, Inc.