Have I found the leak? (picture)

[ajsdoc]

I posted before that I've had to top up the central heating pressure more recently.

I initially isolated the boiler and thought it was a leak from the boiler as I got a pressure drop. I then realised I probably didn't have the system completely cool when I isolated it like an idiot. Did again, topped to 1.5 when completely cold, left for 48 hrs and it didn't move at all. When I opened the valves the pressure dropped on the guage indicating a pipework issue I think.

Balloon over prv pipe dry.

I've been under the house and lifted a few easy carpets upstairs, no obvious water loss. None from radiators or valves.

I noticed there was an access panel in the boxing carrying pipes from the boiler to upstairs so in desperation I stuck my camera in and took a picture. The angle's a bit odd but they are pipes running upwards in boxing then I think there may be a leak at an elbow at the top under the bathroom floor.

My question is have I found it, or does this look like something you might get after soldering? It looks not right to me! It's on a pipe that gets hot when the water is on, 2 other pipes get hot with the heating on so I presume these are pipes heading to the cylinder coil.

So does it look like a leak and would a leak on this pipe cause my pressure loss? I hope so, finding this little leak has taken over my life!

Sorry that's a long post to ask a simple question! It's a plumber next to get to it and hopefully fix if you think I could have found it.

 

[terryplumb]

If its wet ,and its on a central heating pipe ,you would certainly lose pressure there. Is it wet ? I can't tell ,but it looks dry ????

 

[ajsdoc]

Just out of reach in the boxing! May try and make the hole a bit bigger.

When you say central heating pipe, this pipe (and the one next to it) gets hot when the hot water is on, not the heating. But I assume it's the same system water? (He says embarrassed at his ignorance)

 

[terryplumb]

I have no idea what boiler or heating system that you have ,but if you have a combi boiler and the pipe in question gets hot when you run a hot water tap ,that pipe will not contain water from your sealed central heating system. And will not cause a pressure drop if it has a leak.

 

[ajsdoc]

Sorry. Not combi. Worcester 30cdi system boiler, S plan, unvented cylinder. I put just the heating on for a bit, then just the hot water to identify which pipes are getting hot when.

It was found after having the boiler in a year or two to be on a one pipe system, so we had it repiped as a two pipe system just a year or two ago.

 

[Crofton Gas]

Looks like scale from a leak...

 

[terryplumb]

OK ,then the pipes that get hot ,when there is a demand for hot water are going to /from the cylinder coil. And if indeed they are leaking ,would result In pressure drop.

 

[terryplumb]

Looks like scale from a leak...

Also looks like a pain in the ass to get to !!

 

[ajsdoc]

Yep, of that much I'm sure!

 

[gasbanni]

Check visually the ceiling under the joint ....If it is leaking it will show some staining not be necessarily be wet, just to confirm that you have found it.

 

[ajsdoc]

It kind of sits over the void created by the boxing. I've left heating and hot water off overnight, managed to get my fingers up in the boxing to the crusty bit of pipe and no obvious water...

Is it possible to isolate the cylinder hot water circuit and just use the immersion for a couple of days. I presume then if pressure still falls the "hot water tank circuit" (I don't know the proper name) would not be to blame. If I top back up, use the immersion and just have the central heating on would this adequately isolate the hot water tank pipework?

 

[terryplumb]

On your boiler there are flow and return pipes for central heating ( 22 mm ),and flow and return pipes to the hot water cylinder ( I would expect these to be 15 mm) take a look and confirm. The pic may be misleading ,but the suspect pipes look like 22 mm to me. Anyway the flow and return to cylinder can be isolated at the boiler ,when cold, to take them out of the equation .

 

[ajsdoc]

Thank you. Pipes in question (heat up when water heating on) are 22mm as you say. It's 22mm coming from both 2 port valves under the boiler.

Unfortunately the area does seem completely dry, so guess this could be a red herring too.

This pressure drop is so frustrating.

Think plumber next, I'm really grateful for everyone's help.