 |
Common appliance switches include rocker, toggle, slide, and contact (tamper) switch.
The back side of a toggle switch inside a food blender.
A thermostat inside an electric heater.
|
Appliance controls are the devices that turn things on and off, regulate temperature, speed, duration, and otherwise control appliance functions. Appliance controls include switches, thermostats, rheostats, and timing mechanisms. Some appliances, such as toasters, use mechanical controls while others, like microwave ovens, use digital controls. Knowing how they work will help you fix just about any of them.
Appliance switches vary in complexity and functions. Switches operate by making contact with the conductor of an electrical circuit. When an appliance is plugged in, it's connected to an electrical circuit in your home. Power runs through the wires of the circuit to the appliance. When the appliance's on-off switch is turned on, electricity flows through the switch to operate the appliance. There are several common types of switches: push-button, toggle, rocker, slide, and throw switch.
Other appliance controls are also switches. Rheostats, thermostats, solenoids, and timers, for example, are all types of switches. These components operate inside appliances to turn on motors, open and close valves, control heating elements, and turn on different parts of the appliance during different cycles, such as the rinse and spin cycles of a washing machine. Test and service a switch:
- Unplug the appliance and disassemble enough to access the switch. Disconnect one lead from the switch.
- Set the multimeter on RX1 (resistance times 1) scale. Clip probes to the switch terminals or leads. Turn the switch on (for multispeed switches, press one switch at a time and note each reading). Zero ohms means the switch is okay. High or fluctuating ohms means the switch is broken or dirty.
- Clean any switch contacts with a small file or with electrical contact cleaner. Contacts should make firm connection when the switch is on. If they don't, replace the switch rather than repair it.
- Use electrical contact cleaner to clean less accessible switch contacts. In order to work cleaner into the switch, operate the control buttons as you spray the cleaner into apertures. Don't overspray.
Test and service a large-appliance thermostat:
- Unplug and disassemble the appliance enough to access the thermostat.
- Hook the clip of the multimeter to one lead of the thermostat and touch the probe to the other. Or you can touch one probe of the multimeter to each terminal. The reading should be zero.
- Turn down the temperature control dial; you'll see the contact points open at the thermostat. The meter should stop buzzing when the contacts open.
- If the thermostat is faulty, replace it with a new one, following the manufacturer's instructions.
Test and service a small-appliance thermostat:
- Unplug and disassemble the appliance enough to access the thermostat.
- Set the multimeter on RX1 (resistance times 1) scale. Place one probe of the multimeter on the output side and one probe on the input side. The reading should be zero.
- Replace the thermostat if faulty.
|
Related Articles
Related Tips
Related Videos
