It's as per photo at:

https://flic.kr/p/2hAcV3x

The photo is the front facing bleed valve from one of two double rads
and so I can easily get to these. All the other rads have the bleed
screw facing the wall so I have ~2" to work in.



But that *is* a square radiator plug/bleed valve. I wouldnt use a
hex socket on it though. Too much chance of rounding it off. The key I
posted a link to earlier should work on the ones behind the radiator.

Tim

Tim


Very short square - hence importance of filing the chamfered end off the
key - otherwise it won't fully engage.