On Fri, 30 Oct 2020 18:56:25 +0000 (GMT), Dave Plowman (News) wrote:

In article ,
PeterC wrote:
Assuming you have a rad in that room, why not a combination gate
valve/drain point. With some hose to get it outside.

Not sure that I'd want to use a gate valve anywhere, judging by their
'performance' on open systems. Had more fail to work than have worked.

The gate valve on a rad is only to balance the flow. Works fine for that.
Although some these days are the same valve as you get with the TRV.

Not so critical then, also any additive in the system should keep it
working.
--
Peter.
The gods will stay away
whilst religions hold sway