You should spend about 20 minutes on this task.
The diagram below shows how a central heating system in a house works.
Summarise the information by selecting and reporting the main features, and make comparisons where relevant.
Write at least 150 words.
Sample answer
This diagram provides an overview of a domestic central heating system. It shows how the tank, boiler and pipes ensure a constant flow of hot waterto both the radiators and the taps.
The cold water enters the house and is stored in a water storage tank in the roof. From there ü flows down to the boiler, located on the ground floor of the house.
The boiler, which is fuelled by gas or oil, heats up the water as it passes through it. The hot water is then pumped round the house through a system of pipes and flows into the radiators, located in different rooms. The water circulates through the radiators, which have small tubes inside them to help distribute the heat, and this warms each of the rooms. Some of the water is directed to the taps to provide hot water for the house.
Once the water has been through the pipes and radiators, it is returned to the boiler to be re-heated and circulated round the house again.
(171 words)
