MANUFACTURED GAS IN THE HOME. 17 
e. Flues should be fitted to prevent back drafts and smothering 
of flames. 
STEPS NECESSARY FOR CORRECT HOT-WATER HEATING. 
a. The gas must be burned in a Bunsen (blue-flame) burner with 
perfect combustion. Yellow flames must never be used. The inner 
cone of the Bunsen flame must not touch the metal surface of the 
water heater. 
b. The heat produced by the burning of the gas must be trans- 
ferred to the water in the most direct manner possible. The low 
efficiency of so many heaters is due to the inadequate heating surface 
so that the water does not have a chance to properly absorb the heat 
that has been produced. 
c. The combustion products should be cool when they leave the 
heater and carried to a flue. The flue should be fitted to prevent 
back drafts and smothering of flame. 
d. Automatic water heaters are of two classes : 
(1) Instantaneous, where the flow of water starts the gas. These 
use gas for short periods at high rates of flow and may disturb the 
pressure conditions in the neighborhood. 
(2) Storage with thermostat control. These use small rates of 
gas flow for longer periods but only to maintain a set water tempera- 
ture in the tank. 
e. If any form of storage is used, the heat delivered to the water 
should be held in; that is, the storage tank should be property insu- 
lated to cut down the radiation losses. Insulation of hot- water pipes 
from heater to where they enter walls is also desirable. 
/. With any form of storage tank the use of a thermostat for 
controlling the gas will result in better service and less gas con- 
sumption. 
g. The heater or tank must be properly connected, cold water 
introduced at the bottom, and the hot water removed at the top. 
Provision should also be made for draining and blowing out of 
sediment. 
LIGHTING SHOULD BE FROM INCANDESCENT MANTLE LAMPS ONLY. 
The incandescent gas mantle lamp is simply a Bunsen burner where 
the burning gas heats the material in the mantle to incandescence, 
thereby producing light. The lamp must be closely adjusted if effi- 
cient and satisfactory results are to be obtained. Hissing or roaring 
sounds are indicative of excessive or bad adjustment. Adjust the 
lamp by adjusting the air shutter and gas needle valve of the 
