Central heating - how it works?
A central heating system provides warmth to the whole interior of a building (or portion of a building) from one point to multiple rooms. When combined with other systems in order to control the building climate, the whole system may be an HVAC (heating, ventilation and air conditioning) system.
Central heating differs from space heating in that the heat generation occurs in one place, such as a furnace room in a house or a mechanical room in a large building (though not necessarily at the "central" geometric point). The heat is distributed throughout the building, typically by forced-air through ductwork, by water circulating through pipes, or by steam fed through pipes.
The most common method of heat generation involves the combustion of fossil fuel in a furnace or boiler. Increasingly, buildings utilize solar-powered heat sources, in which case the distribution system normally uses water circulation.
In much of the temperate climate zone, most new housing has come with central heating installed since the Second World War, at least. Such areas normally use gas heaters, district heating, or a oil-fired system, often using forced-air systems. Steam-heating systems, fired by coal, oil or gas, are also used, primarily for larger buildings. Electrical heating systems occur less commonly and are practical only with low-cost electricity or when ground source heat pumps are used. Considering the combined system of central generating plant and electric resistance heating, the overall efficiency will be less than for direct use of fossil fuel for space heating.
Źródło: https://en.wikipedia.org/wiki/Central_heating
Boiler - what is it?
A boiler is a closed vessel in which water or other fluid is heated. The fluid does not necessarily boil. (In North America the term "furnace" is normally used if the purpose is not actually to boil the fluid.) The heated or vaporized fluid exits the boiler for use in various processes or heating applications,12 including water heating, central heating, boiler-based power generation, cooking, and sanitation.
Źródło: https://en.wikipedia.org/wiki/Boiler
Number of persons employed in the company hydraulic
Hydraulic Company may be established by a qualified plumber who already has some experience. Prior to founding the company will have to obtain the necessary permits for this to officially start a business. Therefore, in addition to plumbers, employ the accountant and secretary, and benefit from the support of legal counsel. Then the professional conduct of the hydraulic will not be a problem at all, and only worry remains the employment of suitable plumbers who will conscientiously carry out their tasks. The larger company hydraulic may be employed for about ten plumbers and those responsible for its daily functioning.