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Types of Valve

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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.

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Fitting and Replacing Taps

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Taps are fastened to sinks, baths, basins, etc, with washers and nuts. In the bathroom, they may have mastic between the body of the tap and the fitting instead of a washer or gasket, with a plastic or rubber washer underneath. Sink pillar taps are usually fitted with a plastic or rubber washer/gasket above and a ‘top hat’ washer underneath.

In either case, the nut must be tightened with a special basin spanner, designed to reach up behind the sink, basin or bath. This spanner is also used to turn the nut on the tap connector fitting. Alternatively, proprietary fittings, such as the Speedfit tap connector, may be used. These need only be tightened by hand.

With sink, bidet and basin mixer taps, the tap tails are often plain pipe. These allow push-fit fittings to be used as an alternative to the conventional compression or soldered fittings.

Fitting and Replacing Taps

For ease of fitting, flexible connectors can be used, or lengths of plastic pipe. Alternatively, flexible corrugated copper tube connectors can be used, but these must be handled with care. Do not flex or bend them more than once, otherwise they may crack and leak.

To replace or fit new taps, the water supply to both t~ps must be turned off and the pipes drained. The old taps should be disconnected from the supply pipes (use an old towel to mop up the water that may spill from the broken joints). After removing the old taps, clean away any old mastic from around the tap holes, taking care not to damage the surface. Then fit the new taps, with their washers in the correct positions. Reconnect the pipes to the taps (adjusting the length if necessary), and restore the water supplies.

Above left Two-hole bath/shower mixer.

Left High-neck kitchen pillar taps.

Improving Taps Appearance

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An inexpensive way of improving the appearance of old taps is to use a conversion kit to replace the cross-head and easy-clean cover with a shroud head, which simply fits on to the top of the spindle. Sanitaryware manufacturers produce ceramic tap heads, colour matched to their suites, but these may only fit their own ranges of taps, so check before buying.

Improving Taps Appearance

Mixer Taps

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There are several types of mixer tap, so called because they have two inlets and only one outlet. There are major differences between them, and the correct type must be selected to comply with the Water Byelaws.

Mixers may have divided flows, where the mixing only occurs at the end of the spout, or they may be designed so that the hot and cold water mixes in the body of the unit. If the hot and cold water are both supplied from a cold water cistern, either type may be used. However, if the cold water comes from the mains supply, and the hot water from the cold storage cistern, only the divided-flow type may be used.

If both hot and cold water come direct from the mains, either type of mixer may be used, but if the unit is a bath/shower mixer with a flexible hose, each supply pipe, or the shower hose, must be fitted with a double check valve to eliminate any possibility of back~siphOflage. This assumes that an air gap exists between the tap outlet and the overflow level of the basin or bath. If not, double check valves must be fitted to the pipes from the mains.

The single-hole mixer usually has supply pipes of 12mm, or possibly 15mm, diameter and may, or may not, incorporate a connection for a pop-up waste. Three-hole mixers are similar to two-hole mixers, but have the extra hole for a pop-up waste.

Mixer Taps

Most two- and three-hole mixers have screwed BSP connections, but most single-hole mixers have plain (or plated) copper tube. Basin mixers have inlets at 102 or 210mm (4 or 8in) centres, and bath mixers at 18 1mm (7¼in) centres.

Two- and three-hole mixers have normal tap heads, or levers, on each supply to control the flow. Single-hole mixers may be operated by separate tap heads on each supply, or by the more modem single lever. The latter controls both the rate of flow and the mixing proportions of hot and cold water in the one action.

Bib Taps

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At one time, the bib tap, which is screwed into a fixed wall plate elbow, was rarely used for anything other than garden water supplies. However, the development of in-wall pipe systems has led to outlet connections that are wall plate elbows, fixed so that they are flush with the wall (tiled) surface. These require a form of bib tap, which screws into the wall.

Bib Taps

Pillar Taps

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Single taps, normally called pillar taps, are usually mounted one on each side of a washbasin, through purpose-made holes, or side-by-side on the bath. Each tap is secured by a backnut screwed onto the threaded portion, or tail, which fits through the hole. The threaded portion is normally ~4in BSP for basins and sinks, and Y4in BSP for bath taps. (Note Kitchen sink taps are usually much taller than basin taps. This allows room for a bowl to be placed in the sink, underneath the taps.)

Pillar taps

There are several types of pillar tap:

• The rising-spindle type, where the whole spindle moves as the tap is opened.

• The more common, non-rising spindle type, where the spindle lifts the washer assembly.

• The Supatap, no longer made, but for which replacement washers are still available.

Taps and valves

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Both taps and valves perform exactly the same function:

they control the flow of water. The difference between them is that a valve is fitted in a pipe run, while a tap is fitted at the end of the pipe. Also, since valves are usually hidden, they are not normally given the decorative finish applied to taps which, invariably, are highly visible and often need to blend with a room’s decor. A tap’s decorative finish also prevents corrosion, which otherwise would occur on the bare brass from the effect of soaps and other chemicals in normal household use.

Taps and valves

Although many different styles of tap are available, actually there are only a few types. Tap selection will depend on personal choice of style, in combination with the type required and the system in which it is to operate.

The latter is an important point, because continental taps, designed to operate on high-pressure systems, will not work well on the conventional low-pressure systems common in the UK, where the hot and cold supply is fed from a cistern (usually in the loft). Similarly, taps designed for low-pressure UK systems may not work effectively on mains-pressure or unvented systems. The type of tap is also important, particularly in the selection of mixer taps.

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