Anybody who has had to spend a night in a cold house due to a busted central heating system knows the importance of a heating system.
If you’ve ever thought of how your heating system boiler works, this is going to be an introduction to the domestic heating system.
The Easy Part!
Your home’s heating system works in the following way. A thermostat is placed in the living area with a temperature that is set to a lower limit at which the heat is to be maintained. Whenever the ambient heat drops below the limit, a circuit closes, which lets current flow towards the hot water circulator signaling the radiator to begin the heating process. In some countries, the heating system has been configured so that the water re-circulates continuously. This in turn, signals the boiler to turn up the heat.
The water then begins to circulate through a device which helps capture and purge air from the heating system. Domestic heating systems also include an expansion tank which controls the volume of water in accordance to the changes in water temperature. In the newer heating systems, the expansion tank is placed right next to the boiler. In the older systems it is placed in the attic.
Turns out, producing heat is easy. Getting it to where it is needed around the house is the hard part. The water (steam) passes into the distribution system that carries the heat throughout the home with the help of radiators. Hot water or steam radiators use an oil or gas fueled boiler to heat the water before circulating it through radiant baseboards or piping in walls and floors throughout the home. As the water begins to circulate through the pipes, convective and radiant equipment, it releases heat energy and cools down. While in some of the heating systems, gravity is used to get the circulating water back to the boiler. The newer heating systems use a pump that not only helps circulate the water throughout the entire home, but also pumps the water back to the boiler, and the whole process begins all over again.
Boilers only operate when the water has reached a certain temperature that is below its threshold. In many cases, is around 185 degrees Fahrenheit. Boilers use temperature sensors that signals when to ignite the burner or turn it off.
Oil fueled boilers use an oil pump to deliver oil to an atomizing nozzle at high temperatures which then sprays into the fire chamber. There the furl is ignited with the help of a high voltage spark that’s created by a transformer.
Gas fueled boilers use a control valve that allows gas into the burner before igniting the fuel with the help of either a pilot light or electric ignition.
Boiler combustion air
A burner blower or air intake provides the necessary combustion air in the fire chamber. Various safety devices ensure that the flame is present to consume the fuel or else the burner shuts down. The combustion gasses that result from the fuel burning are contained by the heat exchanger. They are passed through tubes and between steel plates of the heat exchanger. The gas then cool and is vented via an exhaust flue. The boiler stops firing once the temperature threshold of the water has been reached. The circulator then stops the flow of water once the thermostat indicates that it has reached the desired temperature. Boilers can also supply hot water to where it is needed around the house. Otherwise, you can install a separate water heater to do the job.