Academic Writing Task 1 · process diagram

The mechanism of a residential central heating system

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.

Central heating system mechanism

1.Cold water enters the house and fills the water tank
2.Water flows from the tank into the storage tank
3.The boiler heats the water
4.A pump circulates hot water through radiators
5.Hot water is also supplied to taps
6.Overflow pipe manages excess water from the storage tank

Chart redrawn by BandLadder from the data in the original IELTS practice task. Many IELTS practice tasks come from the Cambridge IELTS series (Cambridge University Press & Assessment); all rights in the original tasks remain with their owners.

Band 8 sample answer

The provided diagram illustrates the operational mechanism of a central heating system within a residential property. Overall, the system relies on a continuous cycle of water intake, heating, and distribution, involving both a boiler and a pump to maintain temperature control throughout the house.

Initially, cold water enters the house from an external supply and is directed into a water tank located in the loft, which subsequently fills a larger storage tank. From this storage tank, water is distributed through two primary channels. One path leads directly to the taps, providing domestic hot water, while the other connects to the boiler, which is powered by gas or oil.

Once heated by the boiler, the water is propelled by a pump through a network of small tubes. These tubes facilitate the circulation of hot water through various radiators positioned around the house, effectively heating the living spaces. The system also incorporates an overflow pipe connected to the storage tank to manage excess water. This integrated setup ensures that both space heating and hot water requirements are met efficiently through a single, automated infrastructure.

182 words. Every figure in the answer comes from the chart above.

How to write about process diagrams

Say how many stages there are and where the process starts and ends.
Use the passive and sequencers: first, after this, once, finally.
Keep every stage; a missing step costs task achievement.

interconnected: multiple parts or components linked together
facilitate: to make an action or process easier
subsequently: happening after something else in a sequence
integrated: combined into a single, unified whole system
operational: relating to the way a machine functions
distribution: the action of sharing or supplying something

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Frequently asked questions

What should the overview say?

The diagram illustrates the interconnected components of a domestic central heating system, highlighting the dual function of providing hot water to taps and circulating heat through radiators.

How long should an IELTS Task 1 answer be?

At least 150 words; 170 to 200 is the safe range. Spend about 20 minutes on it and leave 40 for Task 2, which carries twice the marks.

How do I describe process diagrams?

Say how many stages there are and where the process starts and ends. Use the passive and sequencers: first, after this, once, finally. Keep every stage; a missing step costs task achievement.