Thanks plumbbob. With the mains off, the boiler now seems to have self-drained :( . Is there any reason I can't cap the pipes near the DHW cylinder (pipes 3 and 4 in the picture I linked above) instead? It's just that the boiler pipework is much less accessible, and amongst a rats nest of other pipe...
Hi. I have an old and now broken central heating (CH) and hot water (HW) system, which (I googled) is based around an 'open vented indirect hot water cylinder' (exactly like this [url]https://www.diydoctor.org.uk/project_images/domestic_hot_water_systems/Indirect%20cylinder.jpg[/url]. All the cold t...
