Electrics and gas
A capped gas point sits beside a back boiler the seller says is unused. What cap was not dismantled to prove the boiler is isolated?
The cap itself was not dismantled, so the back boiler has not been proved isolated. A capped gas point sits beside it, and the seller says the boiler is unused. The survey can record the cap and the seller's words. It has not taken the cap off, not tested the pipe, and not confirmed that the boiler is disconnected from gas. A cap that stays on is a cap that was seen. Isolation is a gas-safety conclusion the inspection did not reach.
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?
Back boilers hide in fireplaces, and a cap on a nearby point is often offered as proof they are dead. Proof would mean someone competent opening the cap, testing, and saying what the pipe still feeds. The home survey does not dismantle gas fittings, and it did not do so here. The seller's statement is a statement. It may be right. It is not a tightness test and it is not a dismantled joint. Buyers should not remove the cap themselves to settle the question.
Ask a Gas Safe engineer to confirm whether the back boiler is isolated, by whatever check is proper, including the cap the survey left in place. Tell the solicitor the survey has not proved isolation and has only the seller's word plus a cap that was not opened. Do not write to a lender that the boiler is safely dead. The report has not said that.
What should you ask your surveyor?
- Did you see a cap without dismantling it?
- Has isolation of the back boiler been left unproved?
- Is the seller's 'unused' a statement rather than a test?
What are the typical next steps?
- Treat the cap as seen, not as a proved isolation.
- Do not take the cap off yourself.
- Ask a Gas Safe engineer to confirm the boiler is isolated.
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
If the fireplace is boarded up, is the boiler gone?
Boarding hides the opening. It does not prove the boiler has been removed or isolated. The cap beside it was not dismantled. The survey has the seller's word and an unopened cap. Neither one is a gas-safety proof that the appliance is dead.
Does an old service sticker on the boiler count as isolation?
No. A sticker is a mark from some earlier visit, not a cap the survey dismantled. Isolation was not proved. The sticker does not show what the pipe still feeds. Gas safety remains a separate inspection from reading an old label.