the ceiling, from which point it is then carried down to the top of the boiler and connected, as appears in Fig. 307. If the flow pipe can be run higher than to the ceiling-to the ceiling of the

FIG. 307.-Heating of Range Boiler on Floor Below Range.

next floor above, for instance the results obtained will be so much the better.

In carrying the flow pipe vertically through the greater distance, it is given more opportunity to cool, and therefore falls to the boiler more readily. A difference in temperature is necessary in all circulation work. The greater vertical rise of the flow pipe

also gives a greater weight of water, which is essential in systems of this nature. By means of the method shown in Fig 307, a storage of hot water can usually be obtained, sufficient in amount if the demands upon the boiler are not too great. The chief

Not to
Xixtures

FIG. 308.-Boiler Heated by Range on Same Floor and Range on Floor Above.

difficulty in connection with the proper solution of this problem is the collection of air at the top of the loop. Unless provision is made to relieve this air, it will very quickly make the system inoperative.

If there are fixtures on the floor above the range, the remedy

is easily applied by taking a supply pipe from the top of the loop to some fixture that is in common use, as, for instance, a bath-room lavatory. If the system is under tank pressure, of course the expansion pipe from this high point will do the work. If, however, the system is under direct pressure, and there are no third-floor plumbing fixtures, the relief of the high point cannot be accomplished in a satisfactory manner. The only thing that can be done under these circumstances is to place a pet cock at the high point, by means of which the air may be relieved when necessary by opening it by hand. Since this method is not automatic, it is open to strong objection, and the only way in which it may reach any degree of satisfaction is to see to it that some. one opens the valve at frequent stated intervals. A drip pipe to the sink should be run from the pet cock. Another way in which this problem sometimes presents itself is to be seen in Fig. 308, where not only a range above the boiler, but also a range on the same floor as the boiler is to be used. This problem is not so common as the previous one, but sometimes occurs when the boiler must for some reason be located in the basement, and it is required to heat it from the laundry stove in the basement and the kitchen. range on the first floor. The best feature about these circumstances is that when the greatest amount of water is requiredthat is, for washing purposes-the laundry stove, which is connected in the ordinary manner, will be in operation, and will usually be able to provide amply, whereas it would be difficult often to get a sufficiently abundant supply from the upper range. The work shown in Fig. 308 does not bring in any features different from those encountered in the preceding problem.

CHAPTER XXVI

HOT-WATER SUPPLY FOR OFFICE AND APARTMENT
BUILDINGS, ETC.

THE principles governing hot-water supply are naturally the same, whether it be in relation to small residence work or to the more extensive systems of large buildings.

In the latter work there is not only a much larger quantity of water to heat and distribute to various parts of the building,

FIG. 309.-Connections for Horizontal Boiler and Tank Heater.

but, owing to the fact that there are often in these buildings hundreds of people making use of hot water, the perfect and continuous operation of the system becomes a necessity. This makes it necessary that the piping be run on correct principles, and that mains and branches be of sufficient capacity to properly perform

their work. On small hot-water systems a serious error may not prevent the furnishing of hot water after a certain fashion, serving only as a matter of inconvenience to a few, while the same error on large work would produce great inconvenience to a very large number of people.

Hot water is generally furnished to large buildings by a special heater, such as shown in Fig. 309, located in the cellar or basement and connected to a large hot-water tank, which may be of the horizontal type, as in the above-mentioned illustration, or of

FIG. 310.-Connections for Vertical Boiler and Tank Heater.

the vertical type, as in Fig. 310. The horizontal tank hung from the cellar timbers is the more generally used of the two types, the principal reason being that it is less in the way than the vertical tank. As far as the connections between heater and tank are concerned, they are similar to those of the kitchen range and boiler, and therefore whatever has been stated concerning the latter applied to the former also.

In addition to the use of water heaters for tank heating, live and exhaust steam are also used, in connection with steam coils