There are several types of valve other than taps:
• The stopvalve (or stopcock) is fitted on the rising main, and may incorporate an integral drain valve. The internal pattern of this valve is similar to a tap, with a spindle, jumper and washer. Unlike a tap, it usually has compression fittings at each end, and is marked with arrows to indicate the direction the flow of water must take through the fitting.
• A gate valve contains a ‘gate’, or paddle, which is raised or lowered by a spindle to control the flow, Usually by turning a wheel handle. It should be kept in the fully open position (or just slightly closed to prevent jamming), and may be fitted either way round. Again, compression fittings are standard.
• A ball valve has a ball with a hole in it to control water flow. It needs only a quarter turn from fully open to fully closed, and is usually fitted with a lever handle that clearly shows whether the valve is open or shut. In the fully open position, this valve provides a full bore opening, which offers less resistance to flow than other types of valve.
• A servicing valve is a form of ball valve, but is usually turned on and off with a screwdriver in a slot, or a knob or short lever, such as is common on washing machine valves. Servicing valves should be fitted before all taps to allow easy maintenance, and to allow easy system balancing, which is important on mains-pressure and unvented systems.
All of these types of valve rarely give problems. Gland
packing can fail in time, and can be replaced in the same
manner as that of ordinary taps. Washers rarely fail.
With the exception of ball valves, all are prone to sticking in the open position, simply because they are not moved often enough. Stopvalves and gate valves should be turned off and on regularly, if only a few turns, to make sure they do not seize up. They should be left a quarter-turn closed after being opened fully. This won’t affect flow, but should prevent sticking in the future.
If a valve does jam, a little penetrating oil or spray should be applied, repeatedly if necessary, until the valve is free. Undue force should not be used; it may damage the valve, or even the pipe.
 |
| Types of Valve |
Above right Quarter-turn ceramic disc mixer with pull-out spray.
Centre right The Speedfit tap connector allows for simple hand
tightening to provide a leak-proof seal.
Right A ‘%in stopvalve showing typical signs of leakage from the gland around the shaft, together with a chrome-plated 15mm stopvalve for exposed positions.
117
Unknown I like the way you present the post. Very clear and useful for a newbie like me. Absolutely great Bathtub Taps with valuable tips. I enjoyed reading your blogs. Thanks for sharing such points. I am impressed!!