CENWAT Hot Water Systems (Unvented/Vented) 2

Question 1

What is the recommended stored hot water temperature to prevent Legionella bacteria growth in domestic systems?

Accepted Answer

60 degrees C

Answer

40 degrees C

Answer

50 degrees C

Answer

70 degrees C

Question 2

What is the purpose of the expansion vessel in an unvented hot water system?

Accepted Answer

To absorb the increased volume of water as it is heated

Answer

To store additional cold water

Answer

To boost the water pressure

Answer

To act as a secondary heat exchanger

Question 3

How often should the temperature and pressure relief valve on an unvented cylinder be manually tested by the householder?

Accepted Answer

Every 6 months

Answer

Weekly

Answer

Monthly

Answer

Annually

Question 4

What is the maximum recommended length of the discharge pipe from a tundish to the termination point for D2 (22mm) pipe sizing?

Accepted Answer

9 metres

Answer

3 metres

Answer

18 metres

Answer

27 metres

Question 5

What must be visible at the tundish of an unvented hot water system discharge arrangement?

Accepted Answer

An air gap between the relief valve discharge and the downstream pipe

Answer

A pressure gauge reading

Answer

A thermometer reading

Answer

A flow meter reading

Question 6

Under Building Regulation G3, what is the maximum storage capacity of an unvented hot water system that does NOT require Building Control notification?

Accepted Answer

15 litres

Answer

No exemption, all sizes require notification

Answer

75 litres

Answer

150 litres