Fitting ID

[Bon]

Hi, and good day to you.

I was wondering if any of you learned folk would be able to assist with identifying this fitting?

I'm referring ot the one with the black cap, not the lockshield

Thanks in advance

 

[MeldrewsMate]

It would help to know what is in the pipe....
It could be a rudimentary pressure or flow regulator, or a pressure relief valve (probably not with an isolating valve downstream though).

 

[Bon]

Sorry, you’re quite right!!

It’s a single-pipe heating circuit within a dwelling

 

[kidgreen61]

Looks a bit like a bypass valve?
Others will recognise it, not seen one like that before.

 

[Nige F]

It's a cyltrol valve = used to be fitted on the return pipe of a gravity circuit next to the hot water cylinder ( hence CYL con TROL ) basically like a thermostat in a car engine but adjustable . An unusual setup you have there