Figure 7-3. - Typical building water supply system.

Figure 7-4. - Corporation stop.

provides for circulation of the hot water at all times. The circulation is created because warm water tends to rise and cold water tends to fall.

The circulating system shown in figure 7-2 is known as an overhead feed and gravity-return system because of its construction. This type of system tends to become airbound, preventing circulation of the hot water. Since air collects at the highest point of the distribution piping, the most practical way to relieve the air lock is to connect an uncirculated riser to the line at that point. Any air lock that develops is relieved when a fixture on the uncirculated riser is used.

Piping and Fitting General Requirements

A typical building water-service line is shown in figure 7-3. This line is composed of a corporation stop, a flexible connector, a curb stop, a stop and waste valve, and a meter stop or gate valve.

Figure 7-5. - Flexible gooseneck connector.

The corporation stop is installed at the location (fig. 7-4) on the water main where a tap is made. Its function is to make the removal of the taping machine and the installation of the remaining fittings easier by securing the water flow from the tap. A corporation stop may not be needed if you are installing building service lines from a newly installed, unpressurized water main.

When you install the line between the corporation stop and the curb stop, use some type of flexible connection for joining the pipe to the corporation stop. This flexible connection protects the corporation stop from strain or damage that can result from any movement of the water main or service pipe because of settling, earth movement, or expansion and contraction.

Several types of flexible connectors are used. The type you choose will depend on the type of material used for the supply line. A gooseneck (fig. 7-5) is used when galvanized iron or steel