The Stop Tap:
The stop tap is a valve and a washer that is inserted into the mains pressure supply pipe to control the water flowing through it. A stop tap is usually kept turned on, being turned off only when necessary to cut off the supply. It must be fitted the correct way (there is an arrow to show the direction of flow). Most stop taps have a crutch handle. Vauxhall Plumbers tradesmen can work with all valves.

Drain Valve:
This valve is a tap without a handle and is opened by turning the spindle with a drain valve key. It is normally kept closed, but has a ribbed outlet for attaching a hose when a system is being drained. A drain valve is fitted in those parts of the plumbing system that cannot be drained through household taps, for instance, in the boiler or central heating systems and on the rising main.

The Gate Valve:
This valve is an isolating valve with a wheel handle, through, which the water flow is controlled by raising or lowering a metal plate (or gate). It can be fitted either way round and is normally used in low-pressure pipes such as supply pipes from a storage cistern. With the gate open, the flow is completely unrestricted. When it is closed, the seal is not as watertight as a stop tap. A Vauxhall Plumber is trained to drain systems.

The Service Valve:
The service valve is a small isolating valve and is operated with a screwdriver. This turns a pierced plug inside the valve to stop or restore the water flow. It is normally used in a low-pressure supply pipe to a tap or ball valve to cut off the water for repairs. A similar valve with a small lever handle and a threaded outlet is used to control the flow to the flexible supply hoses of a washing machine or dishwasher.