OFTEC Solid Fuel key terms

A safety device fitted in the fuel line of an oil-fired appliance that shuts off the oil supply automatically if the temperature rises above a set limit, or if the valve is manually tripped.

The pipework carrying fuel oil from the storage tank to the burner, typically of copper or steel, sized and routed so the burner receives adequate flow and pressure.

A container for storing heating oil, commonly bunded to contain leaks, positioned with suitable clearance, support and protection so that fuel can be drawn safely to the appliance.

A secondary containment wall or integral outer skin around an oil tank that holds the contents if the primary tank leaks, sized to hold the full capacity plus allowance for rainwater.

The pressure, measured in bar, at which the burner fuel pump delivers oil to the nozzle; it must be set to the manufacturer's figure for correct atomisation and combustion.

A small precision component in an oil burner that atomises fuel into a fine spray at a stated flow rate and spray angle, matched to the appliance's heat output.

The measurement of flue gas composition, including carbon dioxide or oxygen, carbon monoxide and temperature, used to set an oil or solid fuel appliance for safe and efficient burning.

A check in which a sample of flue gas is drawn through filter paper and compared with a shade scale to grade the level of unburnt soot produced by an oil burner.

The steady pull of air up a chimney or flue, measured in pascals, that draws combustion gases from the appliance and must sit within the range specified by the manufacturer.

A flue arrangement for room-sealed appliances in which combustion air is drawn from outside through one duct and flue gases are discharged through another, both terminating together.

A vertical structure of masonry or other material that carries combustion products away from an appliance and provides the buoyancy needed to maintain a steady draught.

A tube or sleeve, often of stainless steel or flexible material, inserted inside a chimney to contain flue gases, protect the structure and provide a suitable route for products of combustion.

The process of removing soot, tar and deposits from a flue and appliance, carried out regularly to reduce the risk of chimney fire and to keep the flue passage clear.

A black powdery deposit of unburnt carbon formed when solid fuel or oil burns with insufficient air or at too low a temperature; it can block flues and increase fire risk.

Fuel burned in solid form, such as coal, anthracite, peat or wood, which requires a grate or hearth, a supply of combustion air and regular removal of ash.

The part of a solid fuel appliance on which the fuel bed rests, usually with openings that let primary air pass up through the fuel and allow ash to fall away.

A removable metal tray beneath the grate of a solid fuel appliance that collects ash falling from the fuel bed so it can be taken away safely.

Air admitted below or through the fuel bed of a solid fuel appliance to supply the oxygen needed for the main combustion of the fuel.

Air introduced above the fuel bed to burn gases and smoke released by the fuel, improving combustion efficiency and reducing visible smoke.

An adjustable flap or slider on an appliance or flue that controls the amount of air entering or leaving, used to regulate burning rate and draught.

The fire-resistant floor area beneath and around a solid fuel appliance that protects the building fabric from heat, sparks and falling fuel.

A water-filled heat exchanger built into or behind a solid fuel fire that transfers heat from the fire to water for radiators or a hot water cylinder.

A heating system connected to the atmosphere through a vent pipe and fed from a feed and expansion tank, so water can expand without excessive pressure building up.

A small tank, usually in the loft, that keeps an open vented heating system filled with water and allows for the expansion of water as it is heated.

The total resistance of the path taken by fault current from the electrical installation back to the supply source, used to confirm that protective devices will operate quickly enough.

A residual current device that monitors the difference between live and neutral currents and trips the circuit when a small earth leakage current is detected, giving protection against electric shock.

The connection of metal parts, such as pipework and tanks, to the main earthing terminal so they sit at the same potential and cannot create dangerous voltage differences.

The current value at which a fuse is designed to melt and break the circuit, chosen to protect the cable and equipment it supplies from overload.

The enclosure containing switches, timers, thermostats and protective devices that control the operation of a heating appliance and its pumps or fans.

A device that senses the air temperature in a room and switches the heating on or off to hold the space at the set temperature.

A sensor clamped to a hot water cylinder that switches off the heat source when the stored water reaches the set temperature.

A device that moves heat from a cooler source, such as air or ground, to a warmer space using a refrigerant cycle, delivering more heat energy than the electricity it consumes.

The ratio of heat delivered by a heat pump to the electrical energy it uses, quoted for stated operating conditions; a higher figure indicates greater efficiency.

A water vessel added to a heating system to store heat and smooth short cycling, helping a heat pump or biomass boiler run steadily at lower flow temperatures.

A solid fuel appliance that burns wood pellets, chips or logs to heat water for a central heating and hot water system, needing fuel storage and regular ash removal.

A renewable system using panels or tubes to collect heat from sunlight and transfer it to water stored in a cylinder, often working alongside a conventional heat source.

A control strategy in which the flow temperature of a heating system is adjusted according to the outdoor temperature, improving comfort and efficiency at milder conditions.