A boiler is simply the most important part of a central heating system as it generates the heat that warms up the home or property. Basically, the appliance or small furnace makes use of gas, LPG or oil in order to fuel its operation. However in the UK, most boilers are usually fuelled by natural gas which is supplied automatically from the national gas grid. And depending on how it operates, there are various types of boilers.Typically, a gas central heating boiler will have multiple pipes entering from underneath. While one pipe supplies the boiler with gas from the mains gas supply, another pipe allows cold water to enter the boiler to be heated, the last pipe then enables hot water to exit the boiler so it can be distributed around the home.✓ There are fuel jets and heat exchangers inside the boiler. When the heating is turned on, a valve is opened to allow the mains supply gas to enter a sealed combustion chamber in the boiler. There are multiple little valves which permit the entry of the gas before being ignited by an electric ignition switch. These jets heat a metal component in the boiler known as a heat exchanger which works to transfer the heat to the cold water pipe and heat up the water.✓ Once the water has been heated to the target temperature, it’s then pumped through a circuit of pipe which runs around your home by an electric pump.✓ The heated water enter each radiator, is then transmitted via a closed loop and radiates heat into each room.✓ Once done travelling through all radiators, the water then returns to the boiler at which it must have been cooled. Therefore, the boiler will have to reheat following the same process before circulating. The water can only be drained by a professional Gas Safe engineer