Consumer Appliances and White Goods
Consumer Appliances and White Goods
This domain tests refrigeration, washing machines, microwave ovens, induction cooktops and water heaters, including electrical and mechanical fault finding.
Core rules
- A vapour-compression refrigerator has compressor, condenser, capillary/expansion device, evaporator and thermostat. Frost pattern and pressures indicate charge or airflow faults.
- A PTC start relay and overload protector are common compressor starting components. Check winding continuity and insulation to the shell.
- A washing machine uses inlet valve, pressure switch, motor, belt, drain pump and door lock. No drain often means a blocked filter or pump.
- A microwave has a high-voltage transformer, capacitor, diode and magnetron. The capacitor can hold a lethal charge; discharge it and respect door interlocks.
- Induction cooktops need suitable ferromagnetic cookware and detect pan presence; a cracked plate or failed IGBT can stop heating.
- Water heaters need a thermostat, thermal cut-out and reliable earth; never bypass a safety device.
Worked example
A refrigerator compressor hums and trips its overload after a few seconds. Measure winding resistance from common to run and common to start, then start to run. A typical small compressor might show about 5 Ω run, 20 Ω start and the sum between start and run. Infinite resistance means an open winding; a low reading to the shell means insulation failure. Also check the PTC relay and supply voltage under load. If the winding is shorted to the shell, replace the compressor; do not simply fit a bigger overload.
Traps
Touching a microwave capacitor before discharge; opening a sealed refrigeration circuit without training; ignoring a blocked drain filter; bypassing a thermal cut-out; testing a compressor only at no load.