Rayburn regent back boiler pipe work

[Guitarguy]

Hi, at mums house there is an old Rayburn Regent solid fuel which was probably installed in the 60’s. It works well enough but today we noticed damp below where the back boiler pipe work goes up to the hot water tank so I ripped off the boxing and found this.
It seems to be an old tee fitting which has been seeping for years causing a bit of a mess- not too fussed about that as it’s a rolling restoration project the house!
My question is, what is this? It it just an old blanked off tee or is it some sort of valve? obviously I need to stop it leaking whether fit a blank to the leaking end or replace it if it is some sort of valve?

 

[Exedon]

It's a old spring safety valve, is boiler just connected to the cylinder?

 

[Guitarguy]

Hi, it is but via a small black tank which seems to have a 15mm feed to it off each big pipe going to/from the Rayburn. Difficult to say exactly how it’s set up without being there

 

[Exedon]

Difficult to say without a clearer picture of cylinder pipework what's going on.
If cylinder/expansion tank is installed correctly you should be able to get rid of safety valve. Need a clear picture of cylinder pipework from floor to ceiling including tank to be certain.

 

[Guitarguy]

Ok, I’ll have to try and get a better look when I’m over there. Thanks.

 

[Hugh Jaleak]

For what they cost, I'd just swap it out. Piece of mind, especially with a solid fuel appliance. Spring Safety Valves - Brass - Pressure Relief-7513 (bes.co.uk)

I'd also be questioning the suitability of a plastic F&E cistern on a solid fuel appliance, plastic cisterns have been known to collapse when filled with boiling water on several occasions, with tragic consequences.