Boiler emergency Repairs

There are several different ways to provide hot water and central heating. Traditionally’ the hot taps are supplied from a hot water storage cylinder, which in turn draws from a cold water storage cistern in the roof space. Water is heated in the cylinder t>/ a fitted immersion heater and/or indirectly fry a boiler. Hot water is drawn as needed from that stored in the cylinder.

Combi (combination) boilers are increasingly popular, especially in flats and small houses need for a hot water cylinder.

They are no supplied from the rising main so no storage cistern is needed and they provide water heating and central heating in a single unit. The simplified drawing of a combi boiler explains how this type of boiler works. There Older houses and flat conversions sometimes have instantaHeous gas multipoint heaters fed directly from the rising main which only light when a hot tap is opened. There is 110 energy lost from a storage cylinder, so these systems are quite efficient when a substantial amount of water is drawn off. They are not so good, however, when used in quick bursts, for example to wash hands or rinse a cup. As most people now want central heating as well as hot water they have been largely superseded by combi (combination) boilers.

Combi (combination) boilers are increasingly popular, especially in flats and small houses where space is limited, as they cut out the need for a hot water cylinder. They are supplied from the rising main so no storage cistern is needed and they provide water heating and central beating in a single unit.

The simplified drawing of a combi boiler explains how this type of boiler works. There are two circuits so the dirty water that circulates through the radiators does not mix with the domestic hot water (DHW) going to the taps. A divertor valve switches heat from radiators to D#W as required.

returning cooler water goes back into the boiler for reheating and the circulator keeps it all moving. When a tap is opened, cold. water runs through the heat exchanger and is heated, but as it does so the temperature of the boiler falls and a thermostat triggers the divertor valve so hot water from the boiler is sent back into it instead of to the radiators.

A boiler like this will supply hot wetter quickly when the heating is already on, When the heating is off a different system comes into action. Opening a tap causes a pressure drop in the pressure vessel. This operates a switch, which fires the boiler. This takes a few seconds longer and to counter that, some boilers have a small hot water storage vessel built in ready from immediate use. Combi boilers are usually gas fired but there are oil-fired versions too.