Electrical appliance testing falls into two broad categories: hot tests and cold tests. We'll walk you through both.
- Hot Tests: Tests made with power applied to the unit
- Cold Tests: Tests made with the unit unplugged
Over 90% of the time, you will be measuring three different electrical parameters:
1) Continuity
- Use the "ohms" function (Ω) of your multimeter to test for electrical continuity.
- All continuity tests are made with power removed from the appliance—that means having the appliance unplugged.
- The lower the ohms read on the meter, the greater the continuity.
- Most switches, thermostats, and other contacts that are supposed to be closed should read 2 ohms or less if they have proper continuity.
- If you read something higher than this, the electrical control you are testing is probably bad and should be replaced.
2) Voltage
- When testing for the presence of proper voltage, you are looking for either 120 volts AC or 240 volts AC—depending on the type of appliance.
- When testing for voltages at electric dryer heating elements and electric range or stove elements, you are looking for 240 volts AC.
- When testing for control voltages to solenoids, timers, etc., on washers and other 120 volts AC appliances (i.e., they do not require a 240 volt AC plug) then you're looking for 120 volts AC.
- Anything less means you have a problem somewhere in the circuit, usually an open switch or thermostat or one with poor continuity. Sometimes it could be a bad wire connection— look for burnt or discolored wires.
3) Amperage
- Testing for amperage, or current, is another way of testing for continuity. The main difference being that amperage tests are made with power applied to the appliance and the appliance turned on. BE CAREFUL!
- You are looking for readings in the "amps" range (A), not the "milliamps" range.
