The diagram below shows how a central heating system in a house works.
Sample Response
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.
Introduction: First sentence. Overview: Second sentence.
Key features: Entry of cold water into boiler; circulation of hot waterto radiators and taps; return of waterto boiler.
Supporting information: direction of flow; types of boiler; location of radiators; radiator tubes
Paragraph breaks: The paragraph breaks mark stages in the process.
Linkers: and, from there, then, once, again Reference words: it, both, there, which, this
Topic vocabulary: enters, stored, roof, flows, ground floor, located, passes, pumped, system, circulates, heat, directed, returned, re-heated
Less common vocabulary: ensure, fuelled by, heats up, distribute the heat, warms
Structures: An appropriate mix of active and passive structures and a range of sentence types are used.
IELTS Writing Correction
- 1. Name the main components Original: the tank, boiler and pipes Suggested revision: the tanks, boiler, pump and pipes Why it matters: The diagram includes two tanks and a pump as important components of the system.
- 2. Distinguish the two routes Original: a constant flow of hot waterto both the radiators and the taps Suggested revision: hot-water circulation through the radiators and a separate supply to the taps Why it matters: The diagram distinguishes the radiator circuit from the domestic hot-water supply.
- 3. Distinguish the roof tank Original: a water storage tank in the roof Suggested revision: a water tank in the roof Why it matters: The roof tank is shown as feeding the separately labelled storage tank.
- 4. Repair corrupted wording Original: From there ü flows down to the boiler Suggested revision: From there, water flows down into the heating circuit Why it matters: The corrupted character leaves the clause without a valid subject.
- 5. Locate the small tubes Original: small tubes inside them Suggested revision: small tubes connected to them Why it matters: The diagram depicts the small tubes as part of the pipework connected to the radiators.
- 6. Identify the tap supply Original: Some of the water is directed to the taps Suggested revision: Hot water from the storage tank is directed to the taps Why it matters: The diagram shows the tap supply leaving the storage tank rather than branching from the radiator flow.
- 7. Identify the entry point Original: enters the house Suggested revision: enters the roof tank Why it matters: The diagram shows the incoming cold-water pipe feeding the tank at roof level.
- 8. Use concise process wording Original: through a system of pipes Suggested revision: through the pipe network Why it matters: Pipe network describes the connected distribution system more concisely.
- 9. Describe radiator circulation Original: flows into the radiators Suggested revision: circulates through the radiators Why it matters: The arrows show water passing through each radiator as part of the circuit.
- 10. Use precise installation verb Original: located Suggested revision: installed Why it matters: Installed is a more precise verb for fixed heating equipment.
- 11. Clarify heat transfer Original: to help distribute the heat Suggested revision: to transfer heat into the rooms Why it matters: The radiators release heat into the rooms rather than merely distributing it within themselves.
- 12. Tighten result link Original: this warms each of the rooms Suggested revision: thereby warming each room Why it matters: The participial link connects the circulation process to its result more smoothly.
Suggested Rewrites
- the tank, boiler and pipes the tanks, boiler, pump and pipes
- a constant flow of hot waterto both the radiators and the taps hot-water circulation through the radiators and a separate supply to the taps
- a water storage tank in the roof a water tank in the roof
- From there ü flows down to the boiler From there, water flows down into the heating circuit
- small tubes inside them small tubes connected to them
- Some of the water is directed to the taps Hot water from the storage tank is directed to the taps
Why this response received Band 6.5
The process description initially follows a clear sequence from water entry through heating, circulation and return, using mostly effective paragraphs and fluent language. However, it inaccurately merges the roof feed tank and storage tank, oversimplifies how hot water reaches the taps, and then appends substantial study notes that are not part of a Task 1 report. Remove the notes and describe the separate tanks, pump and connected flows precisely.
IELTS Writing Criteria Scores
Task Achievement
The main heating cycle is described and an overview is present, but the separate tanks and tap-water route are misrepresented and substantial irrelevant study notes are included.
Describe the roof feed tank, storage tank, boiler, pump, radiator circuit and tap supply as distinct connected components, and omit all commentary about the writing.
Coherence and Cohesion
The report section progresses logically through the process with effective paragraphing, but the appended labels and notes abruptly disrupt the unified response.
End after the process description and organize the body around cold-water intake, heating and distribution, and the returning circulation loop.
Lexical Resource
The report uses varied and generally precise process vocabulary, with only minor slips such as merged words and a corrupted reference word.
Proofread for small transcription errors and distinguish component names precisely, especially the feed tank and storage tank.
Grammatical Range and Accuracy
Complex and passive structures are used with good control in the report, while errors are occasional and meaning remains clear.
Refine pronoun reference and final proofreading so forms such as the corrupted subject before flows and merged words are corrected.
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IELTS Academic Writing Task 1
The diagram below shows how a central heating system in a house works.
Your response
Write the task yourself, then compare your choices with the annotated response.