Page 529 - 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 7 Central heating systems

Test your knowledge

1 In a modern sealed CH system incorporating a condensing type boiler,
what is the expected temperature difference between the flow and return
if designed correctly?
a 12°C
b 20°C
c 22°C
d 30°C
2 Which pipe within an open vented central heating system allows the
system to remain at atmospheric pressure?
a Cold feed and expansion pipe
b Open vent pipe
c Warning pipe
d Discharge pipe
3 Which heating system incorporates 2 × two-port valves?

a The C-plan
b The Y-plan
c The W-plan
d The S-plan
4 The image below shows a three-port mid position valve. How will the
system function in its current position?

A B

AB

a Hot water only
b Heating only

c Heating and hot water

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