A huge variety of household appliances contain heating elements. The two basic types are the exposed single-wire element, most often used in hairdryers, fan heaters and toasters, and the metal-sheathed element used in ovens, grills, iron sole plates and immersion heaters.
This type of element is simply an exposed length of conductor which heats up when a current is passed along it due to the resistance properties of wire. As it is an exposed conductor, it must be housed and supported in a way that avoids accidental contact which could cause electric shock or burns. It must also be housed in a way that allows the heat generated to dissipate and do the job intended. For instance, a toaster needs a large aperture in which to place the bread so that it rests near the exposed element for it to function correctly. 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 »
The information given here also applies to the grills on many cookers. This is a simple way to ascertain if the control is faulty. Short circuit failures on elements may damage regulators in which case, if you are in any doubt, renew it.
The following test is for a single circuit application, that is, a single element. For double regulators, that is, a double element, the same procedure will be required on both single and double operations of the switch. From off position an anticlockwise turn will put into circuit one element (usually the inner), a clockwise turn from the off position will put into circuit both inner and outer. Check that double regulators operate independently on a half turn each. For singles, use ony a full turn. Read the rest of this entry »
These are among the most frequently used items in the home. Generally, they are very reliable, but when a problem does occur, it is usually at the most inconvenient time. Over the years, ovens and hobs have become increasingly complex with the addition of digital timers, touch controls and other refinements.
It is essential to remember that these appliances are connected directly to the mains supply and, as with any repair, cleaning or service, must be completely isolated. In this instance, the main double-pole isolation switch for the appliance must be switched off and also the fuse for the cooker/hob circuit removed from the main distribution board. If an MCB is fitted in place of a fuse, ensure it is in the off position. Do not proceed with any repair or service if both these requirements are not met and also make sure you advise others who may use the switch of your intentions. Read the rest of this entry »
The toaster is another appliance that uses heating elements and, in most instances, a bi-metal strip thermostat to control the length of time the bread is exposed to them. This, in turn, relates to the degree of browning required by varying the position of the bi-metal contact points. When bread is inserted, a latched spring system is actuated to hold the bread carrier in place. At the same time, it makes a switch contact to supply power to the elements. The heat from the elements toasts the bread and also heats the bi-metal strip, causing it to bend. Read the rest of this entry »
