CENWAT Central Heating System Types

Question 1

In a fully pumped central heating system, how is water circulated to both the heating and hot water circuits?

Accepted Answer

By a single pump with motorised valves directing flow

Answer

By gravity to both circuits

Answer

By two separate boilers

Answer

By thermosiphon action only

Question 2

What is the primary disadvantage of a gravity-fed hot water circuit compared to a fully pumped system?

Accepted Answer

It has slower hot water recovery times due to lower flow rates

Answer

It requires a larger cold water storage cistern

Answer

It cannot be used with a conventional boiler

Answer

It requires a pressurised expansion vessel

Question 3

Which British Standard covers the specification for forced circulation hot water central heating systems in domestic premises?

Accepted Answer

BS 5449

Answer

BS 7593

Answer

BS 6798

Answer

BS 7074

Question 4

In an S-plan central heating system, which valve configuration is used?

Accepted Answer

Two 2-port motorised valves

Answer

One 3-port mid-position valve

Answer

One 2-port motorised valve

Answer

Three 2-port motorised valves

Question 5

What is the minimum height requirement for the open vent pipe above the water level in the feed and expansion cistern?

Accepted Answer

450mm

Answer

150mm

Answer

One pipe diameter above

Answer

Twice pipe diameter above

Question 6

In a W-plan central heating system, what distinguishes it from an S-plan?

Accepted Answer

It uses wireless thermostatic radiator valves for zone control

Answer

It uses a single 3-port diverter valve

Answer

It has no motorised valves

Answer

It uses gravity hot water with pumped heating