Hot-Water System of Heating

63. Equipment for Hot-Water Heat. The hot-water system of heating a house consists of a boiler in the basement or below the level of the lowest radiator. This boiler is designed to heat water as it circulates through coils over the fire (Fig. 30). From the boiler, pipes lead to radiators and an expansion tank, and return pipes bring the cold water back to the bottom of the boiler (Fig. 31).

The heat from the furnace fire causes the water to circulate through this system of boiler, pipes, radiators and tank, due to the fact that hot water is lighter than cold water.

64. Heating Unit. The heating unit of a hot-water system is like any stove consisting of a fire pot and grate. Some are adjustable so that different kinds of fuel may be used. A gas burner is sometimes placed in the fire pot and used for heating a furnace, but this is one of the most wasteful ways of using gas. A real gas furnace is much more economical. The fire and heat from the fire circulate around the coils containing the water. If the coils are not constantly kept full of water, they will be injured by the heat.

65. The Management of the Fire. When burning coal, spread the coal all over the surface of the fire in a thin layer so as not to smother it and thus make it burn with a smoky flame. Keep the ashes cleaned out from underneath the fire and around the fire pot. Clean the flues every forty-eight hours. Soot on the coils is more effective than asbestos would be in keeping heat from penetrating to the water. Regulate the fire with the drafts. Open the one below the fire box to let in air to aid combustion. Open the one found in most furnace doors a very little. This aids in the combustion of gases, thus making more economical use of the fuel, while opening it wider checks the burning of the fire. Broken and warped doors and drafts let in too much air and destroy the efficiency of the heater. Open the chimney damper, shown in Fig. 2, Sec. 3, admitting air to check the draft. Close the chimney or pipe damper of the type of cook stove shown in Fig. 2, Sec. 3, to check the draft up the chimney.

66. The Pipes. The pipe carrying the hot water from the boiler out to the heating system leads to the expansion tank, the sometimes separate pipes lead from the boiler to a radiator. Insulate each pipe, except the part in the room to be heated, with asbestos or some other covering, to keep the heat in it. Keep the pipes full of water. When they are installed, see that they are put in so that they gradually rise upward. If they dip downward at any point, air will collect at these places and check the circulation of hot water thru pipes.

67. Expansion Tank. The expansion tank (A, Fig. 31, and Fig. 32), placed somewhat higher than the top of the highest radiator, is fitted with an overflow, for water expands as it is heated. If the expansion tank is closed so that the overflow pipe will not open except under pressure after the air in the tank has become compressed by the expansion of the water, a higher temperature in the pipes may be reached, but such a furnace must be given more careful attention than one with an open expansion tank. Learn to know the parts of a heating system and how they operate before trying to manage it.

68. Water. Fill the boiler and radiators full of water, and add enough more to partly fill the expansion tank. From time to time, note the height of water in the tank, to know if more must be added. Do not add water when unnecessary, as fresh water tends to rust pipes faster than water from which the carbon dioxide and air have been exhausted. To note the height of water, read the gage.

If there is much sediment in the water used, this must be drawn off from the bottom of the boiler to prevent its accumulating there. When this is done, fresh water must be added to replace the water drawn off. Loss of water from evaporation must also be replaced. No water should be put into the system except to replace such loss. Do not draw the water out of the system, and refill it from time to time. The practice of changing the water in the furnace rusts it more than keeping the same water in it all the time.

69. Radiators. Radiators (B, Fig. 31) are made of rather complicated coils of pipe, so often an accumulation of air lodges in them. This interferes with the circulation of the water and the radiator does not get hot. There usually is a vent (A and B, Fig. 33) attached to each radiator to let out air which collects there. If a radiator does not heat well, open the air vent until the air ceases to flow from it and water comes; then close it. Valves should be placed at places where cold water collects in bad plumbing.

In very cold weather, do not entirely shut off the valve of the pipe leading to any radiator, as the circulation of a little warm water is needed to keep it from freezing. Radiators may be placed under the floor (Fig. 34) when so desired.