QUESTION 11
(a) (i) State the purpose of a relief valve on a mains pressure hot water cylinder.
(1 mark)

  (ii)  A mains pressure hot water cylinder has two relief valves. State which valve should operate
first and explain why.

(2 marks)

(iii) State where relief valves are fitted on a mains pressure hot water cylinder.
(2 marks)

(b)   Name TWO devices installed on a high pressure cold water supply to ensure that other
components in the system are protected.
1
2
(2 marks)

(c)   Describe an alternative method to using a supply tank for a low pressure hot water cylinder that
does not require an open vent pipe.
(2 marks)

(d)  (i) What is the minimum temperature at which hot water should be stored in a hot water cylinder
(1 mark)

(ii) Give a reason for this.
(2 marks)
Total 12 marks

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