Showers must have some kind of mixing valve to mix the streams of hot and cold water and thus to produce a shower at the required temperature. The two handles of the bath taps provide the very simplest mixing valve, and push-on shower attachments can be cheaply obtained. Opening the bath taps then mixes the two streams of water and diverts them upwards to a wall- hung shower rose. These very simple attachments work quite satisfactorily — provided that the design requirements already referred to are met. However, it isn’t always easy to adjust the tap handles to provide water at exactly the temperature required. Installing A Shower Mixer A bath/shower mixer provides a slightly more sophisticated alternative operating on the same principle. With one of these, the tap handles are adjusted until water is flowing through the mixer spout into the bath at the required temperature. The water is then diverted up to the head by turning a valve. Then there are manual shower mixers. These are standard equipment in independent shower cubicles and may also be used over a bath. With a manual mixer the hot and cold streams of water are mixed En a single valve. Temperatures, and sometimes flow control, are obtained by turning large knurled control knobs. Finally, there are thermostatic shower mixing valves. These may resemble manual mixers in appearance but are designed to accommodate small pressure fluctuations in either the hot or cold water supplies to the shower. They are thus very useful safety devices. But thermostatic valves cannot, even if it were legal, compensate for the very great difference of pressure between mains supply and a supply from a cold water storage cistern. Nor can they add pressure to either the hot or cold supply. If pressure falls on one side of the valve the thermostatic device will reduce flow on the other side to match it. Thermostatic valves are more expensive but they eliminate the need to take an independent cold water supply pipe from the storage cistern to the shower and can possibly reduce the total cost of installation.
Where a shower is provided over an existing bath, steps must be taken to protect the bathroom floor from splashed water. A plastic shower curtain provides the cheapest means of doing this but a folding, glass shower screen has a much more attractive appearance and is more effective. Electric showers
You can run your shower independently of the existing domestic hot water system by fitting an instantaneously heated electric one. There are a number of these on the market nowadays They need only to be connected to the rising main and to a suitable source of electricity to provide an ‘instant shower’.