Pipe leak behind plasterboard?

danrv

nofoollikeold said:

You can't necessarily tell what a pipe in the wall is from the radiator tail.

It may give an idea where it is though.
Would have thought the pipe would be above and inline with the entry into the wall.
Was going to suggest a metal pipe detector. If plastic, the pipe maybe wrapped in foil tape.

ThisIsWeird

Cap066 said:

No, but the immediate area is covered by the shelf and the only way to take the shelf off it to get the screw out & I`m nervous about water then leaking worse. 
 How can I isolate the pipe if needed ?

If you fully depressurise the system, very little water will come out that hole - if hole it is. And you can then stop it using tape as a temp measure.

Before undoing the screw, have a radiator bleed key ready - and check it's working - and a wee bucket. If water does start to come out from a puncture, then bleed a rad until the pressure is zero. (Obvs make sure the heating is off first.) The flow from the leak should stop - and then replace the screw...! Do up the bleed screw when the pressure reaches zero - ie when no more water comes out the bleed screw.

Before any of that, tho', a few Qs:

1) What pressure does your system normally sit at?

2) Have you noticed any largish fluctuations in this pressure, say between when the boiler is off and cold, and when running your CH?

3) Can you ID the safety discharge pipe heading outside through your wall near the boiler - it's 15mm, copper, and either points at the ground, or bends back on itself against the wall? Any drips from the end? If in doubt, rubber-band a wee plastic bag over the end.

Cap066

ThisIsWeird said:

) Can you ID the safety discharge pipe heading outside through your wall near the boiler - it's 15mm, copper, and either points at the ground, or bends back on itself against the wall? Any drips from the end? If in doubt, rubber-band a wee plastic bag over the end.

I`ll look when I get home . So if its dripping , is this the culprit for loss of pressure ?

MikeJXE

Cap066 said:

ThisIsWeird said:

) Can you ID the safety discharge pipe heading outside through your wall near the boiler - it's 15mm, copper, and either points at the ground, or bends back on itself against the wall? Any drips from the end? If in doubt, rubber-band a wee plastic bag over the end.

I`ll look when I get home . So if it's ost dripping , is this the culprit for loss of pressure ?

Most likely 

Lorian

Send photos of the radiator the shelf and where the pipes enter the wall close up. It might be possible to guess which side hit

FFHillbilly

depending on the wall construction, its quite unlikely that the fixings for the shelf have caused this leak if you can't actually see any signs of moisture around there. 
If the fixings do turn out to be dry and you still need to find the cause of your pressure loss have a look here:
https://www.youtube.com/watch?v=KHogrs_OkxM
or here if you have more time:
https://www.youtube.com/watch?v=TW1y3YbGOLE

Cap066

3) Can you ID the safety discharge pipe heading outside through your wall near the boiler - it's 15mm, copper, and either points at the ground, or bends back on itself against the wall? Any drips from the end? If in doubt, rubber-band a wee plastic bag over the end.

Bag over the end 2 days, not a drop. Thanks for the tip though 

ThisIsWeird

Cap066 said:

3) Can you ID the safety discharge pipe heading outside through your wall near the boiler - it's 15mm, copper, and either points at the ground, or bends back on itself against the wall? Any drips from the end? If in doubt, rubber-band a wee plastic bag over the end.

Bag over the end 2 days, not a drop. Thanks for the tip though 

Shame.
Another test, if the pressure drop occurs fast enough to be noticed reasonably quickly, say within a couple of hours, is to pressurise the system back to 1 bar or just above, note the exact reading, turn off the boiler, and close the two isolating valves you'll find under it that go to the CH flow and return.
Your installation instructions will help you ID these two pipes, but they'll be 22mm and in copper.
You then leave the boiler until such time has passed that a drop would usually be noticed - a couple of hours or so? - then you check the gauge. 
If the pressure has dropped, then the loss must be from within the boiler.
If no drop, then open the isolator valves and look for an instant drop then. If so, the leak is on your radiator side. So chances of a bad screw are higher.