HOUSEHOLD. 



209 



which is, to say the least, annoying; 

 but this objection can be overcome, 

 and cannot be justly considered a dis- 

 advantage. The disadvantages of the 

 hot-air system lie in the comparative 

 high cost of operation, in the rapidity 

 with which it loses heat when the fire 

 becomes low, and in the difficulty of 

 even heating on windy days. , 



The question of the ventilation pro- 

 vided by a hot-air furnace is an im- 

 portant one. The system presupposes 

 a very generous supply of air, which, 

 in properly erected systems, is fresh 

 when brought to the furnaces, is then 

 heated and distributed to the rooms. 

 When so constructed that the air 

 brought to the furnace is taken 

 from the interior of the house 

 itself, the furnace is a source of 

 danger, for the air will become so de- 

 vitalized that it will be absolutely un- 

 fit to 'breathe. The air that is brought 

 in to the furnace from out of doors is 

 likely to lose a great deal of its supply 

 of oxygen, unless care is taken to pre- 

 vent the furnace from becoming too 

 hot. 



Steam Heating. 



Heating by means of steam came 

 perhaps first as a development of a 

 method of heating to overcome the 

 disadvantages of hot- air heating. The 

 essentials of the system consist of the 

 boiler with the furnace beneath, a 

 system of disfributing pipes for the 

 steam, and radiators through "which 

 the heat of the steam is liberated into 

 the rooms. The theory concerned in 

 the operation is quite simple: the 

 water in the boiler is heated, and 

 steam is generated which rises 

 through the pipes to the radiators, 

 some condensation will result, and 

 this is either brought back to the 

 boiler or dispo.sed of in some other 

 way. 



There are two general systems of 

 heating, in the first of which, known 

 as the Gravity Circulation System, the 

 water of condensation from the radia- 

 tors flows by its own weight into the 

 boiler at a point below the water line; 

 in the second, ihe water of condensa- 

 tion does aot flow directly back to the 

 boiler, but is returned by special 

 machinery or in some cases wasted. 

 The latter system is sometimes called 

 the High Pres?ure System, because 

 steam of any pressure can be generat- 

 ed in the boiler, part of which can be 

 used for power purposes. High-pres- 



sure steam, however, is seldom used 

 for heating, but is reduced to not 

 more than 10 pounds by throttling 

 from the boiler or by passing through 

 reducing valves; sometimes the ex- 

 haust steam from engines and pumps 

 is used. 



The iboiler for house heating with 

 either steam or hot water should be 

 chosen very carefully. It should be 

 large enough to contain a suflScient 

 amount of water; the firebox should 

 ■be deep and spacious; it should be 

 easily accessible for cleaning; it 

 should have no joints exposed to the 

 direct action of the fire; a sectional 

 boiler is the better, since no general 

 explosion can occur, should one sec- 

 tion give out; the construction should 

 be durable and good, the very best 

 gauges, safety valves, and other fix- 

 tures should be used, and it should be 

 capable of working to its full capa- 

 city with the highest economy. 



The systems of piping ordinarily em- 

 ployed provide for either a partial or 

 a complete circulatiag system, each 

 consisting of main and distributing 

 pipes and returns. Three systems of 

 piping are in common use. 



In this system the main pipe is led 

 to the highest part of the building, 

 usually the attic, from whence dis- 

 tributing pipes are run to the various re- 

 turn risers, which extend to the base- 

 ment and discharge into the main re- 

 turn. The supply for the radiators is 

 all taken from the return risers, and 

 in some cases the entire return circu- 

 lation passes through the radiators. 



In this system a large steam main, 

 elevated close to the ceiling of the 

 basement, runs around to a point 

 -where the last radiator is taken off, 

 and is then connected into a return 

 main to the boiler. All the water of 

 condensation returns through the 

 same pipe. This system requires 

 only one connection to each radiator. 



Hot-water Heating. 



Heating 'by means of hot water is 

 accomplished by means of circulating 

 hot water in the radiators instead of 

 steam. The entire system, radiators, 

 circulating pipes, and boilers, are filled 

 with water; this water is heated in 

 the boiler. The hot water in the boil- 

 er is light, and has a constant ten- 

 dency to rise, while the water which 

 has lost its heat through the radiators 

 is heavy, and has a corresponding ten- 



