Back boiler
Back boilers are small boilers fitted at the back of the hearth of an open fireplace or in a room heater to provide domestic hot water and sometimes to heat radiators within a dwelling.
Combi boiler or Combination boiler
Combi boilers are boilers that heat water instantaneously on opening a hot tap. There are no tanks in the loft and no storage cylinder. The water is fed from the mains so the water pressure is generally stronger. What is a combi boiler?
Combined Heat and Power
Combined Heat and Power (CHP) is the simultaneous production of heat and electricity. Using a reliable internal combustion engine fed from a single source of fuel, such as natural gas or LPG, a CHP system can produce usable amounts of both heat and electricity.
Heat only
A heat only boiler is a conventional boiler which works in conjunction with a hot water storage and cold water top up tanks to provide both central heating and hot water.
System boiler
A system boiler is filled with water via a temporary connection and expansion is accommodated by a special vessel, which may be inside the boiler (see also expansion vessel)
System
A 'system' is the term used to describe the boiler and all of its components required to provide your home with heating and hot water
Unvented cylinder
The term 'unvented' most commonly refers to cylinders able to store water at mains pressure, thus removing the need for a feed and expansion vessel. Therefore flow rates are usually far superior.
