There are two main types of electric fire: radiant heaters which give off reflected heat from the front of the fire and convector heaters which give off convected heat from the top of the casing, supplying background heat to an area. Some heaters combine the two types, with radiant elements for instant heat and a convector for background warmth.
Electric fan heaters are also available; these work by forced convection, where air is warmed by being blown over a heated element. With this type of heater, the warm air is distributed more quickly through the room than by natural convection.
Changing mains lead
Because of age, heat deterioration or damage from feet, the mains lead on any electric fire is subject to cracks in the outer covering – and this can be dangerous. You should change the lead at the first sign of wear; don’t patch it up with tape and try to disguise the need for replacement. The lead usually passes through the back of the heater and is clamped. Remove the cover to expose the clamp: from here the lead divides to a terminal block, where the switch wires join up. Once these terminal screws are loosened the leads may be withdrawn and replaced. Make sure you buy a replacement lead of the correct rating and with the correct covering to withstand wear and give maximum protection.
These types of heater are particularly useful in areas where constant warmth is required, such as a sickroom, baby’s bedroom or hall. They avoid the risk of burning or fire due to direct concentrated heat, associated with a red-hot bar type of heater; but for safety they should not be installed in bathrooms, airing cupboards or greenhouses where conditions are damp – unless the heater is specifically designed for these conditions. Never place clothing on or near the hot air vent to aid drying; this can lead to overheating and eventual element failure.
It is best to choose a model with a built-in thermostat since this provides control over the amount of heat given and regulates a steady and constant temperature over the required area to give efficiency in terms of comfort and cost.
Parts for most convector heaters are available from the manufacturer by post, together with instructions for fitting them; this is usually the best way of obtaining spares since not many heaters are identical internally and elements and thermostats are made and preset to suit a particular model.
These types of electric fires come in many shapes. Sizes and designs and with two types of element – pencil-bar and silica-glass tube.
Pencil-bars are the traditional fire elements. Element wire is closely wound along a length of fireclay bar with either wire-round connections round a nut and bolt fixing to the internal wiring or, more commonly, caps on each end with built-in terminal connections. Pencil-bars are very reliable and strong, but can take time to give a red glow.
Silica-glass elements, which are generally more expensive than the pencil-bar type, are used in most modern radiant fires. They have an attractive appearance, give out plenty of heat in a short space of time and are easy to change; they are also easily spoilt. The appearance of the element depends on the cleanliness of the glass tube; never use a dampened cloth or polish to clean the glass since, because of its composition, smudges and smears will appear which cannot be removed. Instead you should lightly dust the glass frequently with a clean lint-free cloth. If the elements need to be removed to make it easier to clean the reflector, remember to protect and handle the glass with cloth since fingerprints on a silica tube are unsightly and once the heat has ‘burnt’ them on they are impossible to remove. If tubes are accidentally touched during cleaning or handling, use a liquid solvent to remove the grease from the fingerprint marks.
Many elements often fail at the end connections and show signs of burning on these terminals, usually because dirty or loose and badly fitting connections have been sparking slightly and creating heat, a process known as ‘arcing’. The heat causes burning of the connections and you should on no account fit a new element to bad connectors or terminals; if they are only slightly worn, clean the terminal connections with fine emery cloth until all traces of burning and corrosion have been removed. Make sure the element connections are firm since a loose fit will cause burning of the ends.
If you are buying a replacement element, first measure the exact length of the failed element so you can ask for one of the right size. It is also important to remember the exact make and model number of the heating appliance; on some fires the number can only be seen once the coal-effect is removed since it is stamped on the inside of the base. If a model number is not available, the fixing centres of the element will be needed and also the wattage of the element, if this is known.
Warning When you need to change an element make sure the fire is disconnected from the power supply. Many accidents occur because people start to loosen the terminal screws or remove supposedly ‘dead’ elements while the fire is connected.
It is important the inside of a fan heater is kept free from dust and fluff; besides increasing the risk of fire, a build-up of this type of material can find its way into the motor and its bearings, causing the motor to slow down and possibly fail. A slowly running motor will cause the element to overheat and an overload cut-out to operate so the heater will not function.
To gain access to the inside of the heater, undo the screws which hold the casing in place underneath and remove the casing. Using a clean long-bristled paint brush, carefully dust the motor and fan assembly, the element, overload cut-out and switches. Apply a small drop of light oil to the motor bearings (if not of the permanently sealed grease type) and slowly revolve the spindle by hand to allow the oil to penetrate; wipe off any excess oil.