Page 289 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

Chapter 5 Cold water systems

Transducers

A transducer is an electronic sensor that converts a signal from one form to
another. In large-scale, multi-storey water systems, it senses system pressure
variations and converts a pre-set low pressure into voltage to activate either
the boosting pumps or the compressor feeding the pressure vessel to boost the
pressure to normal operating pressure. Transducers may also be used to sense
over-pressurisation.

Temperature sensors
Temperature sensors are often used to monitor the temperature of large volumes
of stored wholesome, potable water where the installation is of major importance, p Figure 5.41 Water pressure
such as in a hospital, prison or any place where there is a duty of care. transducer with pressure gauge
The Water Supply (Water Fittings) Regulations advise that stored
wholesome water should not exceed 20°C in order to minimise the risk of
micro-bacterial growth.

Cold water storage cisterns

Storage cisterns and the Water Regulations
Schedule 2, Paragraph 16, of the Water Regulations tells us that a storage cistern
supplying low-pressure cold water supply to sanitary appliances, or feeding a
hot water storage system, should be capable of supplying potable, wholesome
water. Various protection measures must, therefore, be included in the design
of the cistern to ensure the water supply does not become contaminated or p Figure 5.42 Water
temperature sensor
unwholesome. To comply with the Water Regulations, cisterns must:
● be fitted with an effective inlet control device to maintain the correct water KEY TERM
level, i.e. a float-operated valve Duty of care: in British
● be fitted with service valves on inlet and outlet pipework connections law, the moral and legal
● be fitted with screened warning/overflow pipes obligation imposed on an
● be covered with a rigid, close-fitting lid, which is not airtight but excludes organisation or individual,
which necessitates that
light and insects a standard of reasonable
● be insulated against freezing or undue warming care is adhered to. If the
● be installed so that the risk of contamination is minimised standard of care is not met,
● be arranged so that water can circulate, preventing stagnation then the acts are considered
● be supported to avoid distortion or damage that could lead to leaks to be negligent and
● be readily accessible for maintenance and cleaning. damages may be claimed
for in a court of law.

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