Whichever fuel the boiler is running on whether it s mains gas oil or lpg it enters a sealed combustion chamber inside the boiler and an electric ignition sets it alight.
Combi boiler sealed central heating system diagram.
No external pump no tanks no external expansion vessel no motorised valves and in many cases item 6 is not needed either.
You should read this page in conjunction with the page on boilers and the page on heating controls.
How a combi boiler system works.
Hamworthy s upton condensing boilers and stratton mk2 wall hung boilers are suitable for installation in sealed heating systems only.
Your combi boiler doubles as a central heating unit by adding a radiator.
The diagrams below show three central heating types.
The boilers fitted to older central heating systems i e.
However our purewell variheat cast iron condensing boiler can be.
A primary heat exchanger.
For central heating 2.
Combi is short for combination.
Combination boiler system diagram often referred to as a combi boiler this type of installation heats hot water as you need it without the need for a hot water storage tank.
System boilers are slowly becoming more common.
Sealed system using a combination boiler the majority of modern combination boilers often include a pump pressure gauge expansion relief valve filling loop and expansion vessel in with the boiler.
A modern condensing boiler maximises fuel efficiency by extracting heat from the latent waste flue gases by means of a condensing system.
Nb not to be confused with vented and unvented hot water tanks which are explained in our guide to hot water cylinders many homes in the uk still have an open vented heating system and in some cases they are the better option for your home.
The vented boiler regular boiler and combination boiler systems probably account for over 95 of water based central heating installations.
Combi system this diagram illustrates how simple the heating system connected to a combi boiler is.
Everyone has a basic understanding of how a boiler works.
Central heating is a really convenient luxury to have.
So in places where space and hot water requirements are limited such as flats these can be very popular systems.
They house two heat exchangers.
Those over 10 years old have a simple heat exchange system which can be as low as 70 fuel efficient.
Hot water is made instantaneously so a hot water cylinder isn t.
An automatic bypass valve is fitted inside most combi boilers by the manufacturer these days.
Many manufacturers are now stipulating a sealed system to ensure system cleanliness and protect the boilers.
The combi boiler doesn t require a bulky storage cylinder and can easily fit into most kitchens or storage cupboards making them the ideal system for houses with limited space.
A secondary plate heat exchanger.
Central heating systems are either open vented or sealed systems.