Electrics and gas
The report places a one-pipe circuit, the furthest radiator and heat the survey did not run in one paragraph. Which of those were inspected, and which were merely named?
The one-pipe circuit and the furthest radiator were identified by sight, as far as the pipes and the radiator could be seen. The heat was not inspected, because the survey did not run it. A one-pipe layout serves radiators in series, so the far radiator can run cooler when the system is working, but that effect was not checked. Naming the circuit is not a temperature reading. The survey has not decided the far radiator is cold, and it has not decided the layout is performing as it should.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
On a one-pipe circuit, water passes from radiator to radiator, and each one gives up some heat before the next. The furthest radiator therefore sees cooler water than the first, which is how the layout behaves, not automatically a fault. You only know what this house is doing if the system is run and the radiators are compared. This visit did not run the heat. The surveyor could name a one-pipe arrangement and point to the far radiator. They could not report how hot it gets.
Tell the solicitor the layout was recognised and the heat was not run, so a heating engineer still needs to fire the system if performance matters to you. Do not describe the furthest radiator as failed. The survey has not said it is cold. If the boiler is gas, a Gas Safe registered engineer is the right person to run and check the appliance. Balancing, if it is needed, is part of that later work. The report has not carried it out.
What should you ask your surveyor?
- Which pipes did you actually see, and where was the circuit only assumed?
- Which radiator did you take to be the furthest on the one-pipe run?
- Was the heating off for the whole visit, or only not run long enough?
What are the typical next steps?
- Treat the one-pipe layout and the far radiator as identified, not heat-tested.
- Do not call the furthest radiator failed.
- Ask a heating engineer to run the system if you need to know how it performs.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Is a one-pipe circuit always worse than a two-pipe circuit?
Not as a finding of this visit. A one-pipe layout can leave the last radiator cooler, which is how that layout works, but the survey did not run the heat and did not compare temperatures. The circuit and the furthest radiator were named. Performance stays untested. Do not replace the pipework on the name alone.
Could the far radiator still heat the room well?
Yes, that is possible, and the survey has not decided either way. The heat was not run, so there is no temperature to quote. Identification of a one-pipe circuit explains where to look. It is not a result. Have the system run if the room matters to you. Until then the output stays unknown.