Boiler servicing and why is it necessary

There are many reasons, so let us have a look at some of the main ones:

For many of us after our house and car our central heating system will be the third biggest single expendure. Our boiler is the most important part of our heating system. The manufacture of our boilers, like the manufactures of our cars, insist on servicing. The boilers will not do what they are designed to do which is to get the best possible heat from a quantity of fuel burned efficiently in a safe and controlled manner with minimal emissions from combustion and minimal ware and tare of component parts.

Combustion (in this case the burning of heating oil, hydrocarbons in oxygen)

This takes place when the oil comes in contact with oxygen at a temperature high enough for combustion to take place for diesel above 56c and for kerosene above 38c each kilogram of oil requires a precise quantity of air to burn completely, for oil boilers each kilogram of oil requires approximately 8.6 cubic meters of air to give 7.0 kilograms of combustion gases typically between 1100 and 1700 degrees centigrade this varies somewhat on the calorific value of the oil and boiler design. incorrect oil- air ratio causes. bad combustion. poor efficiencies. flame impingement. and pollution of the environment due to unnecessary production of the poisonous gases, sulphur dioxide, nitrous oxide and the killer carbon-monoxide.

Boiler main parts and their functions

1 Fire box

This is where combustion takes place the burner is fitted on to this box with an air tight seal. The box has a refractory lining the flame should not touch any surfaces of the box or the burner. When the flame does touch surfaces we get a common condition called flame impingment. Flame impingment can be caused by incorrect oil-air ratio, incorrect nozzle type fitted or blockage or even part blockage of nozzle by contaminates in fuel , dirty fuel oil filters, build up of soot on nozzle. incorrect oil ? air diffuser ( blast tube ) fitted or build up of soot on diffuser flame impingement on blast tube and nozzle will eventually cause over heating of burner and components parts resulting in burner failure and expansive repair bills. Flame impingment on fire box and bottom baffles surfaces will eventually burn firebox refractory lining and bottom baffles.

2 Boiler heat exchanger

This is where the heat from the hot gases of combustion are transferred to the water in your heating system. The water in your heating system passes through an arrangement of water passes which draw the heat from the hot combustion gases through the heat exchange surfaces there is also an arrangement of baffles usually steel in the spaces between the water passes these channel the combustion gases to the water passages surfaces increaseing the time it takes the combustion gases to travel through the heat exchanger to obtain the most suitable heat transfer rate for that boiler design the gases continue to the atmosphere through the flue arrangement. baffles may be arranged so there is small passes in to flue gas expansion areas. soot build up on heat exchanger surfaces, soot is a good insulator so the build up on heat exchanger surfaces reduces the heat transfer rate to the water resulting in a loss of heat up the flue to the atmosphere, more oil has to be burned to achieve the required temperature, end result poor efficiencies.

3 Burner

This is made up of many component parts each with its own particular function designed to work in conjunction with all the other components to supply the fuel, air, ignition and burning of oil with some built in safety precautions in place: electric motor / oil pump / air intake fan / control box / solenoid valves / transformer or electronic spark generator / high tension leads / electrodes / atomising nozzle / air diffuser, blast tube / photoresistor /

Sunday, March 15th, 2009 Uncategorized