Page 404 - 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

By using trace heating, the additional cost of the extra pipework for the
secondary return and its associated pump and running costs is removed.

INDUSTRY TIP

Trace heating can also be
used as frost protection on
cold water systems.
p Figure 6.39 Trace heating

System components and controls

You will be able to describe the layout and operational requirements of
hot water system components including the location and safety features
for unvented/vented hot water systems, with consideration of standard
components:

● line strainers
● pressure reducing valves
l single check valves
l expansion devices (vessel or integral to cylinder)
l expansion relief valves
l tundish arrangements
l application of composite valves
l safety features – including expansion and temperature relief pipework,
vent pipes
● thermostatic mixing valves (TMV2 and TMV3).

You will be able to explain the working principles of specialist components used
in systems including:
● infrared-operated taps
● concussive taps
l combination bath tap and showerhead
l flow-limiting valves
l spray taps
l shower pumps – single and twin impeller

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