Can a pipe be capped off with a radiator valve?

[Enver]

I just had to have the ceiling replaced due to a leak caused by a fractured solder joint in a pipe (which was repaired) but when the ceiling came down, we found a disused pipe which appears to be capped off with a radiator tap or valve. We moved in a couple of months ago and have an unvented system pressurised at 1.5 bar. I’m a bit concerned whether this is a proper way for the pipe to have been left. Unfortunately the plasterer showed me the photo after he had repaired the ceiling. Is it only a matter of time before we get another leak or is it safe to leave it alone? I’d appreciate any advice thank you.

 

[Ricardo Napoli]

Best thing would be to solder a cap on it but that’s just what I would do. Unless it’s dead and just rip it out

 

[Aire]

That looks like an old 10mm radiator feed that has just been pushed under the floor instead of capping it off, probably to save draining down. I'd personally remove it where it tees off the system.

 

[firemant]

Is it definitely water? Is your system piped in microbore?

 

[JCplumb]

It probably won't leak, but you can never say never. If you can get the floorboards up above it then I'd recommend capping it off as close to the tee as possible.
Otherwise I'd leave it as you'd need to undo the work the plasterer did to get to it.
If it does start to pass you'll probably just see a stain in the ceiling and at that point you'll have to sort it out.
It's a dead leg and very lazy plumbing from whoever did it, dead legs can cause issues in heating systems but it looks to be downhill to the valve so won't trap air and may not be a problem.
There's also a chance it's not even connected to the heating circuit anymore, may be worth asking the plumber who sorted your leak out if he saw it and if he checked it out.
You'll notice a lot of 'if's', 'may's' and 'probably's' in what I've just written, nobody can say for sure.

 

[Enver]

Thanks all for your advice.