528 



AGRICULTURAL ENGINEERING 



EXPANSION 

 TANK 



and over. The hot-air system of heating is much less expen- 

 sive, as far as cost of installation is concerned, than the hot- 

 water or steam system. 

 The cost of a first-class 

 furnace with double pip- 

 ing to protect the wood- 

 work from becoming 

 over-heated, in a house 

 of six rooms, ought not 

 to exceed $200. 



The Hot-Water Sys- 

 tem. The hot-water fur- 

 nace with suitable radi- 

 ators represents the most 

 perfect system of house 

 heating, but it is the 

 most expensive of all and 

 is slightly more difficult 

 to regulate. Water is 

 heated by the furnace, 

 and the consequent ex- 

 pansion and reduction in 

 weight cause it to flow 

 to the radiators above, 

 where it becomes cooled 

 and consequently heav- 

 ier, causing it to flow 

 downward to be heated 



Fig. -320. A hot- water heating system, again. An expansion 



The locomotive type of furnace or boiler, . • 1 i i 



although not in general use, is said to be tank IS prOViaeCl aDOVe 



quite satisfactory. ,, ., ,. . , 



all the radiators to ac- 

 commodate the extra volume of the heated water. The 

 success of the hot- water system consists in providing a fur- 



