Electrics and gas
Is a discharge pipe, together with the unvented cylinder tundish, any evidence on where that pipe actually ends, or only a note of what was visible?
No. A discharge pipe seen with the unvented cylinder tundish is not evidence of where that pipe actually ends. The tundish is the open break in the safety discharge, and it shows only the part the surveyor could look at. The pipe may continue to a gulley, a stack or a place the visit never reached. The survey did not trace the end, did not test the safety valves, and has not decided that the termination is suitable. The sentence is a note of what was visible.
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?
An unvented cylinder stores hot water under mains pressure, and the tundish is there so a passing safety valve can be seen dripping. That visible break is not the end of the pipe. The rest of the discharge should finish somewhere water can get away without scalding anyone, but the surveyor often loses the pipe inside a duct, a cupboard or an outside wall. Seeing the tundish and a short length of pipe records the fitting. It does not map the outlet. No valve was operated.
Ask a heating engineer, Gas Safe registered where the heat source is gas, to trace the discharge and test the safety devices. The home survey has not done either. Tell the solicitor the end of the pipe is unknown, so do not write that the cylinder was passed. A dry tundish on the day only means it was not dripping then. It does not show where water would go if a valve lifted. Keep the visible pipe and the unknown end as separate facts.
What should you ask your surveyor?
- How far could you follow the discharge pipe beyond the tundish?
- Was the tundish dry, dripping, or simply not clearly seen?
- Did the pipe disappear into a duct, a stack or an outside wall?
What are the typical next steps?
- Treat the tundish as the visible part of the discharge only.
- Ask an engineer to trace where the pipe ends and to test the valves.
- Tell the solicitor the termination was not confirmed.
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 a dry tundish mean the valves are sound?
No. A dry tundish means no water was passing at the time of the visit. It does not test the temperature or pressure valves, and it does not show where the pipe ends. The survey recorded what was visible. An engineer still has to test the controls. Do not read a dry fitting as a pass.
Is the cylinder itself condemned because the end was not seen?
No. The survey has not condemned the cylinder. It has not traced the discharge past the visible tundish, and it has not tested the safety valves. The unknown end is a limit of the inspection. Whether the termination is suitable is for an engineer who can follow the pipe, not a verdict the report has already given.