Hi, I'm Vance and welcome to Repair and Replace.
Appliances are made up of some basic circuits and components.
Having a good understanding of each component can help you troubleshoot and fix most problems.
All circuits need a continuous path for electricity to flow through.
This is continuity, or a closed circuit.
When a component fails, it creates an open circuit as there is no continuity.
The appliance will not work properly until that component is replaced.
In this Episode we'll learn how to test components for continuity.
In part 1 we'll take a look at fuses, heating elements, and thermistors.
In part 2 we'll look at switches, solenoids, and motors.
Let's begin.
To test a component for continuity first set the multimeter to the Ohms or resistance with tone setting.
Safely disconnect the power, and remove the wires or connectors.
Next, touch each probe to each component terminal.
If there is no continuity then the multimeter will display OL or Open Loop.
This means the component will need to be replaced.
If there is continuity you'll get a reading above 0 ohms,
but the resistance will vary between load or non-load components.
Non-load components such as switches, thermostats or fuses,
provide an unrestricted path for the electricity to pass through.
These will typically have a resistance reading between 0 and 1 ohms.
Load components include heating elements, solenoids, motors, or any component that consumes power.
They will need a specific resistance value to function correctly.
This is different for each component and will vary between models.
Most components in an appliance will either be a switch, resistor, or an inductive coil.
Switches simply connect or disconnect power in a circuit.
This includes door switches, and limit switches.
Resistors restrict the flow of electricity and generate heat
when the current or resistance is high enough.
Heating elements in ovens and dryers, harness this heat in a controlled way.
Thermistors are heat sensitive resistors.
These are used as temperature sensors in refrigerators and ovens.
Fuses are safety devices which are designed to burn up when the current exceeds a safe amount.
Motors and solenoids use coils of wire to generate an electromagnetic force.
Motors use this force to turn blower fans and pumps,
while solenoids control valves and door locks.
Appliances usually have several circuits with a few components chained together.
Any single component can create problems so its best to observe what is and what isn't
working as this will tell you which circuits are affected.
For example, if only one stove element stops working, then it's either a problem with the
element, wires, or the switch for that circuit.
Now if all the heating elements are not working,
then its likely a blown fuse or an issue with the power source.
In any scenario, its best to visually inspect all wires and components
looking for burn or scorch marks around the terminals.
This can also help you narrow down the failure.
Fuses are single use, overload protection devices.
Standard fuses have a thin wire that will melt when exposed to high currents.
Thermal fuses are designed to fail at a set temperature protecting against overheating.
Fuses are used in dishwashers, dryers and in some ovens but it's best to check your manual first.
If an appliance stops working completely it's a pretty good sign that the fuse is blown.
Now if you've reset your home's breaker, and the appliance still doesn't have power,
then check the fuse for continuity.
If there's no continuity, then the fuse is blown and should be replaced.
Keep in mind a tripped fuse is often a sign of a larger problem so its important to do
some further troubleshooting or the fuse may continue to blow.
Heating elements convert electricity into useable heat
by forcing current through a high resistance wire.
This includes oven bake elements, stove elements, dryer heating elements
and even hot surface igniters in gas furnaces.
If your appliance has power but isn't heating properly
then check the heating element for continuity.
Without a continuous electrical path, there is no resistance, and no heat is created.
As well, heating elements will need a specific resistance to heat properly.
For example oven bake elements commonly have a resistance of 20 - 40 ohms.
Whereas hot surface ignitors can range from 30 to 200 ohms.
Thermistors are temperature sensing devices, commonly used in ovens, stoves, and refrigerators.
They have a specific resistance that the control board interprets to determine the temperature.
The resistance changes as the temperature changes.
For example we can test the temperature sensor in a refrigerator by checking the resistance
For this we'll need the temperature chart which is often stored behind
the kickplate or a cover on the back.
To verify that a thermistor is good, we'll have to test the resistance at 2 different temperatures.
At room temperature we're getting a reading of 2.6 kila-ohms
In a glass of ice water, then we'll see a reading of 4.5 kila-ohms
Overtime thermistors can start to wear down and will need to be replaced.
If the resistance is significantly different than its rated value, then it can cause
the appliance to be too cold or too hot.
Hopefully this has helped you become more familiar
with some of the components in many appliances.
In part 2 we'll learn more about switches, solenoids, and motors.
For more troubleshooting on furnace, water heater, furnaces, and appliances,
then subscribe to our channel.
And if you need help, you can call or visit an AMRE location
to talk with our knowledgeable staff.
Thanks for watching.