Page 282 - 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

7 THE SYSTEM LAYOUT FEATURES

OF COLD WATER SYSTEMS FED

FROM PRIVATE WATER SUPPLIES

The UK has more than 500,000 people whose only source of potable drinking
water is from a private supply. There are two methods of pumped supply from a
well or a borehole:

1 pumped supply with pressure control
2 pumped supply with level control.
We will look at each of these methods separately.

Pumped supply with pressure control

This type of system provides directly drawn water at the point of use. Pressure
is maintained within the system by the use of an accumulator (often called
a pressure vessel) and a pump. The accumulator is a vessel that contains air
under pressure and water. The water is contained within a neoprene rubber bag
inside the accumulator, which expands when water is pumped into it under
pressure. The air is then compressed and the pressure rises. As the water within
the accumulator is used, the pressure will drop. At a predetermined pressure,
the pump will start and the accumulator is refilled, raising the pressure to its
operating level. These systems generally operate at 1.5 to 3 bar. This system is
preferred when water treatment is being considered.
Storage cistern

Pressure vessel/accumulator
Impervious strata Pressure switch
/flow controller
Sandstone aquifer
Pressure Gravity
gauge feed
Gate/isolator Non-return
valve valve
Pressurised
distribution
usually to
kitchen sink

Submersible pump

p Figure 5.32 A typical borehole installation with pressure control

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