Emergency Boiler Repair/ 24HR Boiler Breakdown Repair Engineers

How Combination Boiler Works

The combination boiler description applies to an indirect combination boiler where the domestic hot water is heated in a secondary calorifier. See below for more about a direct combination boiler. Our projects section also contains lots of information about central heating of all kinds including oil fired.

Combination boilers combine the functions of a central heating boiler and an instantaneous multi point water heater. They give priority, in the main, to the supply of domestic hot water (dhw). The combination boiler has all its operating components contained within the casing and is typically designed for use within a sealed central heating system.

Installation is made easier by incorporating an expansion vessel, thus eliminating the need for a feed and expansion cistern in the roof space. Like an ordinary boiler it will have a gas fired burner and a heat exchanger. The waterways of both form part of the central heating system. In most of the early designs of combination boiler, hot water from the heat exchanger passes to a diverter valve, which directs the flow to a domestic hot water calorifier or central heating circuit. The calorifier is tightly packed with small copper tubes, through which secondary water flows the moment the hot water draw off is opened. As the water flows it picks up heat from the surrounding primary water in the calorifier. The central heating system is pressurised and needs a relief valve to protect against any build up of pressure in the system.

A pressure gauge on the appliance indicates the operating pressure. A by-pass, connected across the primary flow and return, ensures that an adequate flow of water is maintained. This by-pass may, or may not be a built in feature of the appliance.

The flue arrangements for combination boilers may be open, room sealed, fan assisted & room sealed, fan assisted open, miniature flue/condensing or se-duct. The primary heating circuit of combination boilers should be pre-commissioned, cleansed and treated with a corrosion protector in the same way as any other heating system. In hard water areas, the secondary domestic hot water should be treated with an in-line scale reducer or water softer (See projects section for info on both of these) This will prevent the build up of limescale on the instantaneous water heater and the accompanying reduction in flow rate and water outlet temperature.

With a direct combination boiler the secondary water is heated in one of two ways. The water may pass through pipes which run down the inside, or next to the primary pipes in the heat exchanger, or by passing through a separate heat exchanger which is bolted on top of the main heat exchanger. A direct combination boiler does not need a diverter valve or a secondary calorifier.

In a domestic hot water system where the (condensing) boiler is a replacement for an existing storage cylinder system or a conventional boiler, it is essential that all redundant pipework is removed to eliminate "dead legs" which can hold air and cause air locks. These can also cause cold spots and slow burner shut off.

Example of What we do :

-All domestic & some commercial plumbing heating repair, maintenance, service, installation work carried out , for restaurant, factory, large buildings, large offices, supermarket, shops, schools, colleges all domestic and commercial customers

- recommended by "Time Out" London magazine

- Gas appliance inspection service repair installation

- Boiler diagnostic, Back boiler services repairs

- Dishwasher repair & replacement & installer

- Emergency boiler breakdown

- Emergency commercial and domestic boiler repairs

- Tumble dryer repair

- Plumbing heating diagnostic

- Warm air unit repair maintenance service installers

- Valliant combi boiler installation & repair

- System boiler installation & repair

- Led pipe repair & replacement

- Under sink water filter repair

- D.I.Y. Plumbing Technical consultancy service

- D.I.Y. heating Technical consultancy service

- Poor water pressure or noisy pipes services

- Frozen blocked, leaky burst pipes repair

- Blocked sink repair & services, Blocked toilet solution

- Kitchen drainage, toilet internal drainage

- Internal Kithen Drain, Toilet drain service

- Kitchen & Toilet plumbing installation and repair

- Gas safe (corgi) registered engineer

- Some commercial plumbing and heating service engineer

- Some commercial, all domestic heating and plumbing service engineer, Shower installer

- Low pressure on boiler corgi engineer repair and maintenance

- Kitchen toilet basin sink replacement

- Toilet not flushing

- Radiator leak repair and service maintenance plumber

- Potterton boiler repair and installation

- Biasi boiler services repair and installation

- Pressure drops on boiler

- Burst water pipes gas leak emergency repair

- Energy efficiency boiler system installer

- Gas tightness test

- All service emergency, Plumbing some commercial & all domestic service engineer

- Heating domestic service engineer

- Tilling service