Electrics and gas
The heating was drained down because the house is vacant. What firing of the boiler could the survey not watch?
The firing of the boiler could not be watched. The heating was drained down because the house is vacant, so there was no water in the circuit and no call for heat that the appliance could answer. The survey has seen a cold, empty installation. It has not watched a burner light, has not felt the system heat, and has not carried out a gas-safety inspection. Vacancy explains the drain-down. It does not replace the missing firing.
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?
What a firing would have shown is whether the boiler starts, whether it locks out, and whether heat actually leaves it. A drained appliance cannot do those things, and a surveyor must not invent the result. The case, the flue and the pipe routes can still be described as objects in the room. Gas work, including any safety check, is a different appointment. This visit did not make it. An empty house is a reason the demonstration did not happen, not evidence the boiler is sound.
If you need to see the boiler fire, ask for the system to be filled and then for a Gas Safe engineer to run it, or for the surveyor to return only if watching it run was part of a further look. Tell the solicitor this report did not see firing. Do not write to a lender that the heating was proved. Keep the note as a vacant house with a drained appliance.
What should you ask your surveyor?
- Was the boiler left unfired because the heating was drained?
- Did vacancy prevent any observation of the burner lighting?
- Was gas safety left as a separate inspection that did not happen?
What are the typical next steps?
- Record that the boiler was not watched firing.
- Do not describe a drained appliance as tested.
- Arrange a Gas Safe visit once the system can be filled.
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 programmer screen lights, has the boiler fired?
A lit screen shows a control with power. It does not show the burner firing on a filled circuit. The heating was drained because the house is vacant. The survey still did not watch the boiler run. Power is not combustion.
Can last winter's bill stand in for the missing firing?
No. A bill shows past use of fuel, not this visit. The survey could not watch the boiler fire because the system was drained down. Historical paper is not a gas-safety inspection of the appliance today. Past use is not today's firing.