Unless valves are installed properly, they will not operate efficiently and can cause problems in the system. There are certain precautions you should take when installing valves that will improve their performance and minimize the possibilities of a malfunction. These precautions may be summarized as follows:
1. Always clean out a valve before installation because dirt, metal chips, and other foreign matter can foul it. This can be done by flushing the valve with water or blowing it out with compressed air.
2. Clean the piping before installing the valve. If you cannot flush or blow out the foreign matter, the ends of the pipes
should be swabbed with a damp cloth.
3. Only apply paint, grease, or joint sealing compound to the pipe threads (that is, the male threads). Never apply these
substances to the valve body threads because you run the risk of their getting into the valve itself and interfering with its operation.
4. Install valves in a location that can be reached conveniently (see Figure 9-47). If the valve is placed so that it is awkward to reach, it sometimes may not be closed tightly enough. This can eventually cause leaks to develop in the valve.
5. When necessary, support the piping so that additional strain is not placed on the valve. Small or medium-size valves can be supported with hangers placed on either side. Large valves should always be independently suspended.
6. Sufficient clearance is particularly important when rising stem valves are used. Failure to ensure proper clearance
before installing the valve may cause damage to the disc sealing surface.
