A back boiler
is a device which is fitted to a residential heating stove
A stove is an enclosed heated space. The term is commonly taken to mean an enclosed space in which fuel is burned to provide heating, either to heat the space in which the stove is situated or to heat the stove itself, and items placed on it...
or open fireplace to enable it to provide both room heat and domestic hot water or central heating. The device is a water filled heat exchanger
A heat exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall, so that they never mix, or they may be in direct contact...
enclosed at the rear of the burning chamber with a hot water output at the top of the chamber and a cold water feed at the bottom.
The back boiler is typically used with a gravity feed circuit to the hot water cylinder, with a vent or overflow to prevent excess pressure build up. It can also be connected to a series of radiators to provide central heating but requires an electrical pump to be fitted to circulate the hot water.
A back boiler can improve the efficiency of a stove by acting as a heat-sink and can also act as a method of extracting additional heat from the flue system which would otherwise have been lost.
Manufacturers of stoves with back boilers quote efficiency figures of up to 80% on oil-fed models.
Back boilers require that the hot water
Water heating is a thermodynamic process using an energy source to heat water above its initial temperature. Typical domestic uses of hot water are for cooking, cleaning, bathing, and space heating...
or central heating
A central heating system provides warmth to the whole interior of a building from one point to multiple rooms. When combined with other systems in order to control the building climate, the whole system may be a HVAC system.Central heating differs from local heating in that the heat generation...
system be able to disperse all of the heat captured from the fire, otherwise boiling or overheating of the water can occur. Back boilers are strictly regulated in Ireland
Ireland , described as the Republic of Ireland , is a sovereign state in Europe occupying approximately five-sixths of the island of the same name. Its capital is Dublin. Ireland, which had a population of 4.58 million in 2011, is a constitutional republic governed as a parliamentary democracy,...
and the UK following explosion
An explosion is a rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases. An explosion creates a shock wave. If the shock wave is a supersonic detonation, then the source of the blast is called a "high explosive"...
s relating to incorrectly serviced or installed back boilers.