A back boiler is a device which is fitted to a residential heating

stove A stove or range is a device that burns fuel or uses electricity to generate heat inside or on top of the apparatus, to be used for general warming or cooking. It has evolved highly over time, with cast-iron and induction versions being develope ...

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 system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contac ...

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.

Water circuit

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 usually requires an electrical pump to be fitted to circulate the hot water, some systems can use the gravity circuit to include radiators.

Advantages

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.

Safety

Back boilers require that the

hot water Water heating is a heat transfer process that uses an energy source to heat water above its initial temperature. Typical domestic uses of hot water include cooking, cleaning, bathing, and space heating. In industry, hot water and water heated t ...

central heating A central heating system provides warmth to a number of spaces within a building from one main source of heat. It is a component of heating, ventilation, and air conditioning (short: HVAC) systems, which can both cool and warm interior spaces. ...

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 ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...

and the UK following

explosion An explosion is a rapid expansion in volume associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Supersonic explosions created by high explosives are known ...

s relating to incorrectly serviced or installed back boilers. A gravity circuit is commonly employed to connect the back boiler to an indirect hot water cylinder and sometimes one or more radiators. This hot water cylinder needs to be placed at a higher level than the boiler so that hot water will flow to it from the boiler via convection. This is a safety feature to ensure the boiler will not overheat in case of power outage or failure of the circulation pump Connecting a wood burning stove to central heating: key concepts
/ref>

References

External links

Example of an open fireplace back boiler by Grant Engineering Ltd
{{HVAC Plumbing Heating, ventilation, and air conditioning Boilers