Page 324 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

The City & Guilds Textbook: Plumbing Book 1

low-pressure supplies. They are manufactured to either BS 5433 or BS 1010
for domestic use.

They consist of a brass valve body, a head gear with a rising spindle, a packing
gland and a re-washerable loose jumper plate. Stop taps have an arrow on the
valve body that shows the direction flow of the water.

Tap wheel head

Rising spindle

Packing gland
Packing
Head workings
Jumper and washer

Direction of flow

p Figure 5.87 Internal workings of a BS 1010 tap

Some stop taps have a drain valve built in to the stop tap body, but
Wheel head care should be taken with this type when installing internal water
meters as the drain valve position may allow water to be drawn from
the main without being metered.
Packing gland
Packing Stop taps are available with either capillary or compression
connections to suit copper tubes to BS EN 1057, compression
Non-rising spindle
connections for MDPE and push-fit connections for polybutylene pipe.
Rising gate
Olive Full-way gate valves (low-pressure isolation) to BS 5154
Compression fitting Gate valves are used on low-pressure installations such as the cold
feed to vented hot water storage cylinders and the cold distribution
p Figure 5.88 Internal workings of a full-way
gate valve pipework for indirect cold water systems. They do not have a washer,
instead using a brass, wedge-shaped gate that rises inside the valve.

They are known as ‘full-way’ gate valves because the design allows water to
flow at full bore without much restriction to the flow rate. However, they
should not be used on high-pressure supplies as they tend to allow water to pass
by the gate when the valve is under pressure. They consist of a brass valve body
and a head gear with a non-rising spindle.
Gate valves are also available with a lockshield head to prevent the valve being
tampered with.

Spherical plug valves (isolation)
Spherical plug valves are used for isolation of appliances and terminal fittings
such as taps and float-operated valves. A variety of styles are available, including
with or without a handle (these use a screwdriver slot to isolate the water), or
p Figure 5.89 Full-way gate valve for use with an appliance such as a washing machine.
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