Fig. 277 illustrates a method of connecting the horizontal boiler which is often made use of, but which is open to objection. In the first place, it will be noted that the boiler supply is taken into the bottom of the boiler, at a point directly beneath the outlet of hot water to the fixtures. This means that a stream of cold water will be thrown directly up into the body of hot water, and into the entrance of the flow pipe from the boiler, which would naturally be detrimental to securing the best results from the boiler. Not only should the boiler supply be conducted to the bottom of the boiler, as indicated in the two preceding illustrations, but the hot-water supply pipe to fixtures should be taken out of the end of the boiler which is entered by the flow pipe from the range. Fig. 278 represents another common method of connecting horizontal range boilers, which is open to objections similar to those named in connection with Fig. 277, though the errors are not so serious. As to the use of materials for range connections, lead, brass, and galvanized wrought iron are commonly employed. Probably galvanized wrought iron is most commonly in use. The selection of proper material for this work depends largely on the chemical properties of the water supply, as also, the selection of piping for the entire house supply system. Some waters act very rapidly on wrought-iron pipe, the action being so severe in many eases, that the range connections must be renewed at comparatively frequent intervals, if of this material. Under such conditions, the use of brass or lead is necessary.
Fig. 277. - Wrong Connections for Horizontal Range Boiler.
Brass connections are perhaps the most satisfactory. Lead connections are more liable to sag and form traps, which, as already seen, results in unsatisfactory work. When lead is used on the range connections, it is necessary to use brass boiler connections and water-front couplings. A range and boiler thus connected are shown in Fig. 279. The brass connections make tight by means of ground joints, whereas, in the use of wrought iron, unions with gaskets, or right and left couplings must be used. In the use of lead pipe, wiped joints must be used to connect the pipe with the brass connections. Brass boiler couplings and water-front couplings are also often used in connection with work constructed of wrought iron or brass.
Fig. 278. - The Horizontal Range Boiler Improperly Connected.
Several forms of boiler couplings are shown in Fig. 280. As seen from this illustration, they may be obtained in either the straight or bent pattern, for either lead or screwed pipe. Those designed for lead have plain ends, in order to allow solder joints to be wiped to them.
In Fig. 281 are seen several fittings for range boiler work, made either of brass or malleable iron. Water-back couplings are made in several styles, as seen in Fig. 282, for both lead and screwed pipes. These also are made straight or bent, with short or long spuds. They may also be obtained with an inside thread on one end. In range boiler work, it will often be found that the flow pipe gives out more quickly than the cold-water connection. The reason for this is that there is much more expansion and contraction on the flow pipe, due to the fact that it carries hot water. The continual expanding and contracting of this pipe, as it alternately heats and cools, will in time weaken the pipe and its joints, and cause leakage. Even if the heat of the pipe is comparatively even, and the alternate expansion and contraction not great, it is a well-known fact that a heated pipe will not give as long service as a cold pipe.
Fig. 279. - Lead Pipe Range and Boiler Connections.
In Fig. 283 is shown a special device for use in taking range-connection measurements, known as the center-meter. The device consists of a number of small steel rods and several specially constructed joints. These joints are of aluminum, in the form of small cubes. Through each joint, two holes, slightly larger than the diameter of the steel rods, are drilled at right angles to each other. These two holes are so drilled that they break into each other slightly, at the point where they cross. By so constructing them, a single set-screw tightens both rods. Four of the rods shown in the illustration referred to, are provided with 1-inch pipe plugs. The center-meter is used in the following way: In measuring for the flow pipe, for instance, the two rods having plugs are screwed into the boiler opening and into the water-front opening. By means of the joints, the rods are then placed in the same position that the flow pipe will take. Measurements can now be taken from center to center, and from end to center, or, if desired, the device may be laid flat upon the floor, and the same measurements taken. The joints are also made with a third hole drilled at 45 degrees, thus enabling the workman to take 45-degree measurements. It is, of course, impracticable to provide steel rods long enough to use on long-range connections, and if provided, the plumber would find them awkward to carry. In the case of long connections, the rods may be built out as far as possible from the range and from the boiler, and the measurement for the long run of pipe taken in the usual manner between the two last measuring points. The use of this device will be found to save much annoyance to both workman and customer. In the event of wrong or incomplete measurements, it often becomes necessary for the plumber to return to the shop to get out additional pipe, which is usually much disliked by the customer. The center-meter, if used properly, cannot make these mistakes, even in the hands of an unskilled person.
Fig. 280. - Boiler Couplings.
Fig. 281. - Malleable Iron Boiler Fittings.
Fig. 282. - Water Back Couplings.
Fig 283. - Use of Center-Meter, a Device for Taking Range Connection Measurements.
In the running of hot-water pipes, there is often opportunity for the exercise of judgment. For instance, in Fig. 284 are shown two methods of running such pipes, one of them a correct method and the other incorrect. The tendency of hot water is always to rise. Therefore, the practice of carrying the pipe from the top of the boiler directly down to fixtures on the same floor as the boiler, and to fixtures below, does not afford a natural path for the hot water. It means that the hot water must take a downward and unnatural direction, rather than an upward, natural direction. This practice of running hot-water pipes is, nevertheless, a common one. In the instance of Fig. 284, where a connection is taken from the high point, to supply fixtures above the boiler, any accumulation of air will rise in this connection, and escape through the highest hot-water faucet, whenever it is opened. If it were not for this connection, however, there would be danger of the accumulation of air at the high point, which would interfere with the circulation, and very often cause the circulation to cease entirely.
Fig. 284. - Method of Running Hot-Water Pipes.
The collection of air in high points in the hot-water pipes, is an evil which must always be avoided, as it is the means of endless trouble in both supply and heating systems. The correct method, shown in Fig. 284, consists in carrying the flow pipe from the boiler horizontally above the boiler, and dropping down with branches to the several fixtures. This method provides the more natural path for the hot water, and is in all ways the more satisfactory method of the two. Ordinarily the hot- and cold-water pipes are run parallel and close together. When so run, the hot-water pipe should be carried above the cold water. The reason for this is that as heat rises, the heat from the hot-water pipe will have less effect upon the cold-water pipe, if run above it.
Fig 285. - System of Hot Water Supply without Circulation.