Electrics and gas
An expansion vessel on the heating side of the heat pump has no charge written down. Was the vessel pressure tested?
No. The vessel was not pressure tested. It is on the heating side of the heat pump and no charge is written down, so the pre-charge was neither recorded nor tested. The survey saw the vessel and a blank where a figure might have been. It did not fit a gauge and did not decide the vessel is correctly charged. There is no pressure result. The missing test is the whole of the answer.
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?
The vessel gives heating water room to expand. A wrong charge can drop system pressure or push water out at a valve, but none of that was shown here because the vessel was not tested. An empty label is not a reading. The survey does not issue a building-regulations certificate. Approved Document L is guidance for building work, not a certificate from this visit. The Boiler Upgrade Scheme was not assessed, no eligibility was decided, and no grant figure is stated.
Ask the solicitor for any commissioning sheet that states the vessel charge. A heat-pump engineer can test the vessel and write the figure down. The survey has not booked that test and has not passed the heating side. Do not tell a lender the heat pump was proved because the vessel was there. The charge is blank and untested. Grant questions are separate and are not decided by this report.
What should you ask your surveyor?
- Is the vessel labelled as serving the heating side?
- Does a commissioning sheet elsewhere record a charge?
- What test would put a figure where the label is blank?
What are the typical next steps?
- State that the vessel was not pressure tested.
- Ask for the commissioning record.
- Have an engineer test the charge rather than guessing it.
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
Does the blank label decide a Boiler Upgrade Scheme grant?
No. The survey does not decide eligibility and states no grant figure. The Boiler Upgrade Scheme is a grant route in England and Wales toward a heat pump or biomass boiler, not in Scotland or Northern Ireland. A blank charge is an untested vessel on the heating side. It is not an application. The vessel was still not pressure tested.
Did this visit issue an Approved Document L certificate?
No. Approved Document L is energy-performance guidance for building work. The survey does not issue a building-regulations certificate. It did not pressure-test the expansion vessel and did not record a charge. Any compliance paper is for the solicitor to collect. This visit did not create one.