How Does a Gas Boiler Work: Complete Beginner’s Guide

In this article, the topic “how does a gas boiler work” with several facts will be summarize in a brief manner. Gas boiler is a comparative simple design mechanism device.

Process of how does a gas boiler work:

The process working of a gas boiler is given below,

  • At the beginning of the process the source of the heating, which gives the power the whole mechanism of the gas boiler is actually a natural gas. With help of the pilot light the natural gas is ignited and heat up the boiler’s reservoir tank.
  • In the next of the process when thermostat is started automatically or manually the natural gas of the chamber is allowed to ignition. The mechanism of the process is a gas piping systems which have a numbers of dents to creating an effect of jet.
  • After that, the heat exchanger is heated by the heat which is mainly comes from the flame of the natural gas. The heat exchanger of the boiler included with small fins. The fins of the heat exchanger are made with metal which have higher thermal conductivity, around of it have a pipe which is filled by water.
  • The pipe around the heat exchanger is the part of system of central heating. The pipes are go through by the radiators. Home is the place where thermal energy is transferred from the fins of the heat exchanger to the radiator is.
  • Now the heat is radiate. The process accommodates the boiler in any house to heat by a simple constructed thermal exchanger.
  • A pump which is driven by electric is situated in the same line with the piping system. When the water come back to boiler repeatedly the heat is loosen more than the heat is paddled by the home and boiler gets heated again.

In a boiler fuel combustion explosion can be appear when the flame of the burner is came out. The reason behind the fuel combustion explosion in the fuel is happened for loose valve, ignition failure, fault in the gas lines can allow for the build-up of combustion gas in a higher temperature in the vessels of the boiler. The reasons are not only responsible for the fuel combustion explosion but also gasses can be leak for these facilities.

how does a gas boiler work
Image – Gas boiler;
Image Credit – Wikimedia Commons

Gas boiler diagram:

  • A standard gas boiler at the beginning of the process burns the natural gas and heat up water and supply the hot water to the needy. In the process of burning the natural gas a chemical reaction takes place and two by product is produced during this process.The first by product is carbon dioxide and another by product is water vapour.
  • After completing the process the excess amount of waste gas go through by a flue and finally release into the surrounding.
  • Now if we talk about the working principle of the condensing boiler in that case burning the fuel the latent heat of water is produced. Effectiveness of the boiler is increases in this process. For burning up the units are mainly used the vapour and also stretch out additional heat, the water in condensed from the vapour to receive the latent heat.
  • For the heating system of central domestic the units are generally used and heat is cover from the wastage of the gases.
  • The gases are passes by the heat exchanger and the temperature is decreases. After that the gases are condensed and take form of liquid which is directed as condensate. In this way very effortlessly cover some amount of heat which can be ruined. The heat which is used to heat up the cool water, which is comes from the radiator to boiler. A good unit can get a desired amount of energy efficiency which is near about 90%.
  • The gas boilers are all time perfect to use during the replacement of be present gas unit.
  • Perhaps, one of the major efficiency benefits of this unit is the fact it has a pretty large heat exchanger. Large radiators make it possible to lower return temperatures, pushing efficiency higher. An additional benefit is the fact the boiler is cost effective, as the system is considerably under-loaded for the major part of the heating season.
  • Today such boilers become more and more popular due to the great savings they ensure. However, many people state they are prone to major breakdowns. That really depends on the manufacturer, venting and maintenance. Such models are more expensive to buy, but still there are many grants available, which can help to cut down expenses.
  • Gas boiler diagrams can help to find out how the boiler works and whether it suits your needs for heating and hot water. Today they’ve become indispensable during installation of any gas unit. Before buying, make sure the manufacturer has provided you with one.

Gas boiler dimensions:

The gas boiler dimensions which are used are depending upon the size with the number of shower or bathroom. The dimensions needed for the gas boiler in the room is listed below,

  1. For 2 bedrooms house minimum 26 kilowatt to maximum 29 kilowatt gas boiler is required.
  2. For 3 bedrooms house minimum 29 kilowatt to maximum 35 kilowatt gas boiler is required.
  3. For 4 bedrooms house minimum 29 kilowatt to maximum 35 kilowatt gas boiler is required.
  4. For 5 bedrooms house minimum 35 kilowatt to maximum 35 kilowatt gas boiler is required.

How does a gas back boiler work?

The lifespan for the boiler is in between 10 years to 15 years. If the maintenance of the boiler can be done in a proper way then the function of the boiler can go more longer.

A gas back boiler use to heat a fireplace with the help of gas fire or electricity. The cold water comes from the storage tank and reaches to the primary system. After reach to main system the cold water begins to warm and after heating when the temperature of the cold water reaches to desired position, a pump is used to distribute the hot water to output.

The reasons behind the replace a gas boiler:-

The reason behind the replace of a gas back boiler is listed below,

  1. The parts of a back gas boiler maintained and repairing is very difficult for the reason of lack of spare parts.
  2. Back gas boiler are not energy efficient whereas, the modern gas boilers are energy efficient for this reason the electricity bill of the a back gas boiler is too high and electricity bill of a modern gas boiler is too low.
  3. With reports of explosions a back gas boiler is very dangerous.
  4. For government safety and regulation the back boiler are no longer to establish.
800px Energy intensity of economies OWID.svg
Image – :Energy intensity of economies Energy intensity level of primary energy is the ratio between energy supply and gross domestic product measured at purchasing power parity. Energy intensity is an indication of how much energy is used to produce one unit of economic output. Lower ratio indicates that less energy is used to produce one unit of output;
Image Credit – Wikipedia

How does a gas boiler thermocouple work?

Gas boiler such as, gas water heater for maintaining unchanged temperature maintain a periodic cycle which follow on or off system. A huge range of gas boiler contain standing pilot light. Every gas boiler who carried standing pilot light has thermocouple. The function of the thermocouple is to stay open the gas valve when pilot is tight.

Water heater and boiler not the same device but their function is almost same. When the point of maintenance comes at fixed temperature at that time the working principle of water heater and boiler is same. The major difference in between the heating system and boiler system is heating system works in a closed loop system.  

Hot steam or hot water is supplied for a under floor heat system or baseboard radiant. Improper a heating system which turns refilled by cold water whenever hot water is used, with the help of the boiler same water is circulates again and again. Reheating the temperature is important for keeping the house warm.

Will gas boiler work without electricity?

No, without electricity the boiler could not work.

For the working purpose of the boiler need very little amount of electricity but still to run the function of the boiler electricity is required. For ignition of the boiler electricity is required and also to run the function of smart thermostats, back lighting and display screen to heat the home electricity is supplied.


When a gas boiler is working a valve is connected to a gas boiler opens and natural gas is enter to the combustion chamber which is stays at sealed position. After that a ignition system which is driven by electricity or permanent pilot. Then natural gas is ignited and start to burn the natural gas. Hot jet are connected to the heat exchanger within the boiler and heat is transfer from the boiler to water that flows over the heat exchanger.