When extending an existing plumbing system, or installing a completely new system, it makes sense to fit valves of one form or another to the various pipe circuits so that they can be isolated for maintenance and repair work. These can be installed at the same time as the new pipework. However, many old plumbing systems may not have valves to control the various pipe circuits, which means that the entire system must be out of action while any work is carried out. This is far from satisfactory, so at the first opportunity you should remedy the situation.
In some cases, even the rising main may not have a stopvalve to shut off the water supply inside the house, which is something that should be attended to as a matter of urgency. Faced with a major leak, on a cold, wet night, the last thing you will want to do is scrabble about in the dark, looking for the cover of an underground valve that may be under water itself.
The step-by-step illustrations show the installation of a stopvalve and associated drain valve to an existing rising main, but the techniques can be used for installing any type of valve with compression joints. The job is quite straightforward, but it relies on the slight flexibility of the pipework to allow the valve assembly to be sprung into place between the cut ends. To make this as easy as possible, the pipe should be released from any clips in the immediate vicinity. Alternatively, a short length of pipe can be fitted to the valve, with a straight solder fitting slid over the end. This assembly should be fitted in the gap in the pipework, and the solder fitting slid over the joint between the two pipes and soldered in place.
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| Installing a Stop valve |
1:- If the stopvalve is to control the rising main, the water supply should be turned off at the water authority’s stoptap on the supply pipe to the property. Then you can assemble the stopvalve and a drain valve on a short length of pipe. The drain valve should be just above the stopvalve when installed, so that the system above can be easily and completely drained whenever necessary.
2:- It is essential to fit a stopvalve the right way round, otherwise it will not be able to do its job properly. An arrow will be cast into the body of the valve to indicate the direction of the water flow through the valve. Another clue can be gained from the shape of the valve body below the handle: it tapers away in the direction of flow. A gate valve can be fitted either way round; it will accept flow in either direction.
3:- Make sure that the short pipe between the stopvalve and drain valve is inserted fully into each fitting and that the capnuts are tight. Then decide where on the rising main you want to fit the assembly and hold it alongside. Use a pencil to mark the amount of pipe that must be removed from the rising main. A shoulder formed on the body of each valve will give an indication of the cutting point.
4:- Make sure that your pencil marks are accurate. Then carefully cut through the rising main pipe at the points marked. You can use a junior hacksaw, as shown, a small pipe cutter or a ratcheting pipe cutter if you have one. With the last two, you are guaranteed a square end to the pipe, whereas if you use a saw, you must take extra care to cut it squarely. A piece of tape wrapped around the pipe will help.
5:- The most difficult part of the job is springing the stopvalve/drain valve assembly into the gap between the cut ends of the pipe. First slide the olives and capnuts of the fittings onto the ends of the pipe; you can tape them out of the way. Then slacken the capnuts holding the fittings to the short piece of pipe. With everything loose, and a bit of effort, you should be able to spring the valves into place.
6:- Tighten each capnut in turn, setting the positions of the valves as required; the stopvalve handle should face away from the wall so that you can turn it off easily without skinning your knuckles on the wall. With everything tight, and both valves closed, restore the water supply and check the joints for leaks. If all is well, open up the stopvalve to supply water to the rest of the system.
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