Important components of a boiler

A boiler is made up of many individual components which are responsible for the whole heating process. If you are planning to upgrade or buy a new boiler, it is important to understand the most important components of a boiler and their roles. This knowledge will also help you to handle the boiler more effectively and safely. Though there are many types of boilers available all of them have 4 primary components that make up the whole system.


The burner is the most important part of the boiler as it acts as it generates the heat required for the system. The boiler may be manually switched on or by a signal from the thermostat which is pre-programmed by the user, it will indicate the burner that heat has to be produced. On receiving the signal, fuel is pumped inside the boiler from the fuel tank. The role of the burner is to ignite this incoming fuel and start the combustion process. The fuel can be either oil or natural gas and varies from the boiler to boiler, but the responsibility of the burner is to ignite the fuel and start the combustion.

Combustion chamber

This is the where the heat is actually produced by burning the fuel. The combustion chamber is usually made up of cast iron which can withstand very high temperature and pressure. The temperature in the combustion chamber can go up to few 100 degrees in a short period of time. The heat that is generated in the combustion chamber is then transferred to the heat exchanger.

Heat exchanger

This is where the real magic happens. The objective of the heat exchanger is to heat the water from the combustion chamber. It uses a high-pressure zone and a filter to circulate the water around it and distribute heat evenly. It uses a combination of flue passages to flow the water around the combustion chamber and heat the water. The heated water is then transferred to the radiators for heating the rooms.

Fuel sources

Boilers can generate heat from a variety of heat sources like oil, kerosene, natural gas, etc.

Though there are many other smaller components for a boiler, these are the most important parts. It is extremely important to keep these main components in the best of their condition for the boiler to work efficiently. This is why doing an annual boiler service is mandatory in the UK. The annual service not only increases the operating efficiency of the boiler but also ensures your safety. It is also significant to hire only highly skilled and Gas-Safe certified engineers to install or repair boilers in your home. As mentioned above, the temperature in the combustion chamber can raise up 100s of degrees and if the boilers are not installed properly it might lead to a disaster. Combustion chamber should be thoroughly cleaned during the boiler service. It is possible that debris might get accumulated in the combustion chamber over time. They have to be removed and kept in clean condition for it work smoothly.