In our current gaff we have a shower pump to boost two feeble showers.

 

The pump has taken to running for a couple of seconds a few times a day for no obvious reason, or maybe there was a good reason because I've just seen this damp/wet patch (I poked the little hole in the centre) :

 

 

This damp patch is probably in line with the plumbing to one of the showers so I'm guessing that's the culprit. It's tiled above, so I'm about to cut a big hole in the ceiling to try and find out what the problem is.

 

My good lady suggested that I seek your (collective) wise council before I set about it with my multi tool.

 

What's the best way to attack this?

 

Cutting a trap in a ceiling and then patching up with a new bit of plasterboard and skim or tape and fill would be a lot easier than lifting tiles upstairs.

 

Cut a small hole to start with to see how the joists run.  Ideally then cut the trap back to the centre of two adjacent joists once you can see what is where.

Before you cut a hole, is there any chance you can take the downlight out and have a look inside to see if the leak is where you think it is?

 

Water has a habit of running along pipes and dripping down some distance away, so you could end up cutting a hole, only to find that the leak is some distance away.  I've got a USB endoscope thing that works reasonably well if you want to borrow it for a look see.

3 minutes ago, ProDave said:

lot easier than lifting tiles upstairs.

 

@ProDave that's definitely my view, thanks for the backing, I'll pass that on to the good lady. 

@JSHarris

4 minutes ago, JSHarris said:

Water has a habit of running along pipes and dripping down some distance away

 

Thats a very good point that I hadn't considered because my damp patch could be yonks away from the leak.

 

I'll see what I can discover and thanks for the endoscope loan offer.

Take the bulb out and put your mobile up and take a few pics. 

@Declan52 as it happens, we've just been doing exactly that.

 

Great video quality it has to be said but inconclusive results. It turns out that the ceiling we can see is suspended below the original ceiling by about 30mm, so the water has come through 2 layers of plasterboard and a 30mm gap before it's decided to show its face and there is no obvious sign of a leak above the upper (hidden) layer of plasterboard but some dodgy looking plumbing about 8" away.

 

 

I think as @JSHarris said, the leak could be some distance away.

 

Ho-hum

I am guessing that the joists run the "wrong way" and looking from the downlight hole to the drip mark, crosses one or more joists so you can't see that part?

@ProDave no, that second picture I posted is looking through a downlight hole that is not in the first picture and can clearly(ish) see all around the area of the damp patch. That second picture is looking past the wet patch, to the pipes beyond. There is no obvious sign of damp or drips anywhere (apart from when you look up in the kitchen)

Is the bottom layer foil backed by any chance?

 

I guess it's time to have a look through all the downlight holes to see if you can see anything.

No, neither are foil backed,.

 

10 minutes ago, ProDave said:

time to have a look through all the downlight holes to see if you can see anything

 

I think you're spot on with that, good job I didn't set about the ceiling with my saw straight away!

just as an aside to the problem 

you see the green stuff on the copper pipes --thats showing the plumber did not clean all the acid flux off after doing the joints 

In time that could  cause corrosion of the copper pipe ,as you already have the tell tale signs

probably will not rot pipes right through -- but cleaning all copper pipes very carefully after soldering is highly advised  so no active acid flux left behind 

which is why i have already decided to have no joints anywhere that is boxed in by using a pexi  pipe system and manifolds , junctions are in places you can get at  them  in the future

7 hours ago, scottishjohn said:

i have already decided to have no joints anywhere that is boxed in by using a pexi  pipe system and manifolds

 

Likewise John, likewise.

So, I've cut my small hole and found the leak, it's the plumbing for a pumped shower, it doesn't seem to get any worse when the pump is running.

 

How do I fix this? The pipe is quite tight to the underside of the floor above and pretty snug up against a joist. Hints and tips gratefully received!!

 

 

 

 

 

Think I'd cut the 15mm side back and replace it up to the compression fitting. Maybe use another compression fitting if you're worried about the flame with soldering. 

That looks a bit of a b'stard.

 

It's the soldered 15-22mm joint that looks to be leaking.  To re solder there would be tricky, you would want an aluminium plate or some other heat shield slid between the pipe and the flooring before attempting to re flow.

 

I would be looking at a compression repair. If you cut the 15mm tight to the soldered fitting with a hacksaw, or multitool (but it won't do the blade any favours) and de bur with a file I think there is just enough to get a nut and olive for a compression fitting on.  You might also have to cut the existing 22mm back a bit depennding how you do the reduction.

7 minutes ago, Vijay said:

if you're worried about the flame

 

I am, doesn't seem to be enough room to me.

 

7 minutes ago, ProDave said:

That looks a bit of a b'stard.

 

That was my first thought. 

And second thought.

 

9 minutes ago, ProDave said:

depennding how you do the reduction

 

I have no clue!

3 minutes ago, Russdl said:

 

I am, doesn't seem to be enough room to me.

 

 

That was my first thought. 

And second thought.

 

 

I have no clue!

Easiest way is 15mm compression coupler on the right hand end, 22mm compression coupler on the left hand end and short bit of 22mm. reducing coupler, and 15mm in the middle.  That bit can be soldered as it will be soldered out of place.  The coupling piece may end up being too long so you may have to cut back the 22mm end.

 

When you cut the pipe you will be able to see if either end has any slack to push the pipes apart a little.  If not, one of the couplings, probably the 22mm one will need to be a slip coupling,

 

 

I have some bimetal blades for a multitool that will cut copper pipe without too much hassle if that would help.  If anyone is after decent multitool blades for a reasonable price, then I can recommend these people, I've bought quite a lot of blades from them: https://www.saxtonblades.co.uk/fein-multimaster-bosch-makita-compatible-blades

@ProDave thanks, that sounds like it could be a good solution.

 

@JSHarris as I was cutting the hole in the ceiling I was thinking that I needed some new blades for my multitool so thanks for that link and the recommendation, I'll hopefully be armed with a bimetal blade early next week and then I'll set about the repair.

 

What could possibly go wrong?

Keep a bucket handy. In case as you cut into it you find you have not shut off the water to that pipe.

Just now, ProDave said:

Keep a bucket handy

 

Oh, I'll definitely do that.