Portable electric heaters and many fixed electric heaters are controlled by a switch or switches mounted on the frame of the heater. In addition, the heater is switched at a switched socket-outlet or switched fused connection unit or is connected to a non-switched socket-outlet which means pulling out the plug to switch off the heater.
Wall panel heaters, oil filled radiators, convectors and other heaters operating at ‘black heat’ have an integral thermostat which is set to the required room temperature. Read the rest of this entry »
Specific failure symptoms include: 1) The dishwasher won’t complete the dishwasher cycle. 2) The dishwasher has a burning smell during the cycle.
Check the dishwasher wiring for a possible loose connection where it connects to the house wiring.
Check for a circuit breaker in the circuit breaker panel that is defective.
Check the dishwasher timer assembly for erratic operation. If the dishwasher suddenly started when the timer dial is pushed to the ON-OFF position, the timer assembly ON-OFF contacts are defective internally. You will have to replace the timer assembly in order for the dishwasher to program through the cycle properly. Read the rest of this entry »
Capacitors used for motor starting may have metal or plastic outer casings with an insulated top with two terminals. Internally the two terminals are connected to two sheets of metal foil with an insulator between. This package of large surface area is rolled into a cylinder which fits into the shell of the capacitor. As the voltage supplied to one terminal is alternating (at 50 times per second), so does the polarity of its connected foil. An opposite movement of electrons is induced in the other foil, even though they are insulated electrically. This causes a delay in the electrical path, and this, in the case of an asynchronous induction motor, gives the outof-phase feed to the start winding. Read the rest of this entry »
Most labour-saving household appliances contain an electric motor of some description. They are the workhorse of these appliances and most of them are capable of coping with the work loads inflicted upon them. However, some motors, either through poor design or as a result of manufacturers’ cost limitations, are inadequate for the job they are required to do. Adequate or not, at some point it is almost inevitable that they will fail or simply wear out. To delay this, use the appliance with some care and attention, be aware of its limitations and carry out regular inspection and servicing. This will prevent small problems escalating into major ones
Not only do the sizes of motors vary greatly between products, so too do the ways in which they work. To diagnose faults successfully and service or repair appliances, a working knowledge of motors is essential. The following provide a basic introduction to the various types, a description of how they work, the appliances in which each may be found and their particular advantages and drawbacks. Specific problems can be found on individual appliances. Read the rest of this entry »
Aschematic diagram of the internal workings of a pod-type thermostat. This type is used in appliances that have a variable temperature control. It consists of an oil-filled pod connected to the switch by a capillary tube. When the oil in the pod is heated or cooled, it expands or contracts in the tube and operates a diaphragm. The diaphragm acts on the switchgear thus breaking the circuit and in this instance, ‘making’ the other. The cooling oil contracts, pulling the switch the opposite way — back to its original position; the process repeats if temperatures change. Read the rest of this entry »
Isolate the appliance before removing covers or panels for any reason. All tests for continuity should be carried out with a battery operated test meter only.
The most likely cause of overheating will be a failure of the thermostat contact points or sealed pressure system. In such a case you will need to fit a new compatible replacement unit.
Slow initial heating-up times or uneven heat distribution within the oven is usually caused by the failure of one element. Simple testing of the element will highlight the faulty item.
Failure to heat up at all may be either the thermostat or elements. As elements are the easier of the two to check for continuity, a simple process of elimination will indicate where the fault lies. Read the rest of this entry »
Throughout this post, references are made to meters and their use in continuity testing of individual parts of the appliances and their connecting wires. All testing and checking for ‘open’ (not allowing for current flow) or `closed’ circuit (allowing current to flow) must be carried out using a battery-powered multimeter or test meter. Testing should never be carried out on live items under any circumstances. Appliances must be disconnected from the mains supply. Read the rest of this entry »
The brush roll is supported on bearings at each end so the barrel rotates freely. Types of bearings, barrels and brushes differ from model to model as well as between manufacturers. Some manufacturers supply individual parts for the brush roll, such as brush strips, bearings and barrel; others supply only complete assemblies. The brush roll on some models may have removable brush strips, whereas others may be a solid brush roll of wood or plastic with fixed brushes. A small selection is shown here to highlight the differences. Read the rest of this entry »
Cord rewinds are now found on all types of cleaners, from simple hand-operated versions to the fully automatic rewind at the touch of a button. Many auto cord rewind systems use open coil springs and great care should be exercised if a stripdown of these systems is called for. Protection for the eyes is recommended. Goggles afford adequate protection from the spring itself or any item that it may throw out in the event of its slipping from position.
Operation of the cord rewind relies on tensioning of the rewind spring as the cord is pulled out for use. A small brake pad prevents the immediate return of the spring and cord drum to its original position. Read the rest of this entry »
