It seems incredible to think that 100 years ago, just before the outset of the First World War, that something invented by the Romans was still widely unavailable to the human race. In 1910 most houses were heated by a coal or wood fire via a fireplace. Each room requiring a separate fireplace if it was to be heated. Yet 2000 years earlier, the Romans were experimenting with central heating systems brought about by their love of bathing.
The basic idea of central heating is quite straight forward. An easily controllable boiler, fuelled by gas, in an easily accessible place uses water to make heat. This is moved by an electrically powered pump to carry the heat into all the radiators throughout the home. It is both simple and convenient and it makes grey, cold, winter days more endurable. That is if the increasing utility prices do not keep rising. For a property owner in the buy to let sector, having the boiler checked regularly is just as important as having landlord insurance.
The boiler is the most important part of a central heating system. When the home needs heating the boiler is switched on, a valve will then open allowing gas to enter a sealed combustion chamber inside the boiler through lots of small jets, and then an electric ignition system will set them alight.
The gas jets play onto a pipe which contains cold water, this then heats the pipes. The water pipe is just one small section of a large, continuous circuit of pipes that travel throughout the home. It goes through each hot water radiator in turn and then returns to the boiler. As the water travels through the radiators, it will give off some heat and warms all the rooms in turn. When it gets back to the boiler, it has cooled down quite a bit. To keep the water at a high enough temperature to heat the rooms in the home, the boiler has to keep firing. An electric pump will keep the water flowing around the circuit of pipes and radiators.
Gas boilers often double up as a hot water heater. When turning on a hot water tap a valve will open that lets water escape. The water will go through the network of pipes back to the boiler. The boiler will detect that the hot water tap has been turned on. It will fire up and heat the water. However if it is a central heating boiler, it normally has to stop heating the radiators while it heats the hot water, this is because the boiler can not supply enough heat to both at the same time. This is why the boiler can be heard switching on and off when the tap is switched on.