Thanks for all the help chaps.
We currently have threaded iron pipes and I believe the thread is 1/2"BSP as that is a standard size. Measuring across the threads major diameter comes to approx. 22mm, though there is a layer or three of paint on there. 15mm compression fit definitely won't...
We are trying to get our existing non-functioning radiator valves changed for new manual ones. We have 1/2" BSP iron pipe heating pipes and I am struggling to find a 1/2" BSP inlet valve (with 1/2" BSP outlet to the rad). Can anyone recommend a supplier?
Many thanks,
James