the open position. Open and close the valve slowly and at an even rate to reduce the
hazard of a hammer. Unless otherwise indicated, valves are opened by turning the
handwheel or key counterclockwise. Always consult the manufacturer's instructions for
operating a specific type of valve. It is good practice to operate (exercise) valves
Power Operation. Only minimal attention is required for operating power-
operated valves, except in the case of power failure. In this event, consult the
manufacturer's instructions for emergency manual operation. Most power-operated
valves are equipped with safety devices to allow for emergency manual operation.
General Maintenance of Valves, Valve Boxes, and Accessories.
A general valve maintenance schedule is presented in Table 25. Specific maintenance
procedures for various valve types and valve accessories are provided in literature
supplied by the valve manufacturer. Valve boxes should be maintained on the same
basis as the valve maintenance schedule shown in Table 25.
Distribution System Valves. Gate valves are normally used in the
distribution system. These valves are usually equipped with a 2-inch-square (50-mm-
sq) operating nut that requires a valve key for operation. Most distribution system
valves are buried and the operating nut is accessible through a valve box. Common
difficulties with distribution system valves are "lost" valves, inoperable valves, and
valve boxes that have been covered by road work or filled with foreign matter.
Lost Valves. The lost valve problem can be avoided by using an indexed
valve record book in which all pertinent data is recorded, including all valve locations.
The location should be referenced with respect to fixed, permanent markers. If a valve
is lost, use a dip needle, miner's compass, or metal detector to locate the valve box. A
good valve record includes information on maintenance operations performed, tells
whether the valve was opened or closed at the time of inspection, and lists any errors
in location. Keep one copy of the valve record book with the maintenance crew, and
keep one on file.