Pipe leak behind plasterboard?

Cap066

I've noticed a drop in boiler pressure in the past few weeks ( topping up every 10 days or so)
 The only thing I have done recently is put up a small lightweight shelf above a radiator. Just one screw either side of the radiator not directly above. I cut down the rawl plugs and used very short screws but obviously I'm thinking I may have gone into a pipe. So I'm thinking, take the shelf down, pull out the rawl plugs and try to work out if the leak is behind this plasterboard.  Once the holes are there I'd push a long cotton bud through the hole to see if it gets wet.
 If there is a hole in the pipe, then how do I stop the leak? I've read about some special putty to seal the hole... Would this be OK or is there a better method? 

MikeJXE

It only takes one screw, if you take it out it will leak more, even squirt 

AFAIK you will have to access the leak, cut it out and rejoin the pipe, have the parts ready before you start 

Is it copper or plastic ? 

FFHillbilly

if the cotton bud is wet, you'll need to expose the damaged section and repair the pipe, or call a plumber.

Cap066

MikeJXE said:

It only takes one screw, if you take it out it will leak more, even squirt 

AFAIK you will have to access the leak, cut it out and rejoin the pipe, have the parts ready before you start 

Is it copper or plastic ? 

Yeah, worried about opening the leak up even more.   I think it's copper but not sure until I expose it

MikeJXE

Cap066 said:

MikeJXE said:

It only takes one screw, if you take it out it will leak more, even squirt 

AFAIK you will have to access the leak, cut it out and rejoin the pipe, have the parts ready before you start 

Is it copper or plastic ? 

Yeah, worried about opening the leak up even more.   I think it's copper but not sure until I expose it

Cap066 said:

MikeJXE said:

It only takes one screw, if you take it out it will leak more, even squirt 

AFAIK you will have to access the leak, cut it out and rejoin the pipe, have the parts ready before you start 

Is it copper or plastic ? 

Yeah, worried about opening the leak up even more.   I think it's copper but not sure until I expose it

Look where the pipes enter the radiator they should tell you what the material is 

ThisIsWeird

As said above - if you have caused a hole, then the only way to fix it is by gaining proper access to it - messy, but completely sortable. (We can give ideas on this should it come to it. And if you do find it's a punctured pipe, then it may be best if you do this bit rather than leave it to a plumber.)

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, then bleed a rad until the pressure is zero. (Obvs make sure the heating is off first.) The flow from the leak should largely 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.

FreeBear

If you have punctured a pipe, there will be a distinct wet patch around the area of the screw. Does the wall look/feel damp ?

Cap066

MikeJXE said:

Look where the pipes enter the radiator they should tell you what the material is 

of course , yeah ! .. Copper then 

Cap066

FreeBear said:

If you have punctured a pipe, there will be a distinct wet patch around the area of the screw. Does the wall look/feel damp ?

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 ?

nofoollikeold

1. It is perfectly normal to use plastic pipes under a floor / in walls, then a copper "tail" to the radiator.  You can't necessarily tell what a pipe in the wall is from the radiator tail.
2. You can isolate the pipe by freezing it before and after the puncture.  Not usually very easy to do, particularly with pipes in walls.
3. A more certain, more time-consuming, but less expensive solution is to drain the heating system.  How you do it depends on the type of system you have.  Various Youtube videos available.  If you go this route, a good opportunity also to renew the inhibitor.  

FreeBear

Cap066 said:

FreeBear said:

If you have punctured a pipe, there will be a distinct wet patch around the area of the screw. Does the wall look/feel damp ?

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 ?

I would expect a damp patch to be several inches across, and most of it below the leak (if there is one).

To isolate the pipe, you need to know where it runs and then gain access to the ends - Quite likely to be underneath the floorboards upstairs unless you are in a bungalow. If the pipe is leaking, much easier & quicker just to drain down the system (don't forget to add corrosion inhibitor when refilling).