Pinholed pipe and fittings and pipe becomes brittle

[Ray Stafford]

Hi All

A customer of ours has this problem, and is looking for some bright ideas.

The property is a very large country house, with eight bathrooms. The water supply is from a well. He completely refurbed it about 2 - 3 years ago, including new pipe work for the entire hot and cold supplies.

The problem is pin-holes appearing in both the pipe and fittings. Also, where he has cut out affected sections of pipe, the pipe appears brittle, and snaps like the old thinwall Table Z. However, all the pipework is proper modern half-hard table X copper.

Fittings and pipe came from us, and are from different manufacturers. We have no other problems relating to pinholing from the same period.

The water has been tested, with no results that help address this problem. He does use Laco, but I thought the pinholing problems associated with Laco had been sorted out 25 years ago or more.

The only clue is that the problem seems only to occur in the pipework to bathrooms that are unused most of the time, and so are effectively dead-legs.

Any diagnosis or potential solution very welcome. Because of the scale of the job, he really doesn't want to have to re-pipe the whole house if that can be avoided.

Thanks

Ray

 

[mountainman]

Has the water from the 'dead legs' been tested and compared to the water in the more frequently used areas?

I assume that the pipework isn't running in an aggressive environment and is properly earthed.

 

[AlexGas]

Wow, that’s not pretty! Not sure if a sealer will do the trick, might have to rip it out. I use LA-CO, no probs with that at all as long as the system has been flushed. May be an installer was using an old stock!?

 

[AlexGas]

What about the CH? Is it fine?

 

[AlexGas]

Is there a water softener in the system!? You never know…

 

[chris watkins]

Sounds like it could be Blue Water Corrosion, Ray. Page 2 (there is more on the tintenet)
http://www.wras.co.uk/PDF_Files/Commissioning 9-05-01 Dec 08.pdf

 

[Ray Stafford]

Has the water from the 'dead legs' been tested and compared to the water in the more frequently used areas?

I assume that the pipework isn't running in an aggressive environment and is properly earthed.

The pipework isn't in an aggressive environment (already checked that), I have asked him to confirm the earthing, but he is a pretty experienced guy - I would be surprised if it isn't. Worth checking though.

I have also asked him about checking the deadleg water against the "ordinary" water.

Will report back.

 

[Ray Stafford]

Is there a water softener in the system!? You never know…

I will check

 

[Ray Stafford]

What about the CH? Is it fine?

Yep. CH seems ok.

 

[Ray Stafford]

Firstly a correction to timescales.

Install was completed about 4 years ago. First pinholes started to appear after about 2 years and more have appeared since.

Answers to queries:

Yes, water is softened.
No, environment is not aggressive.
Not sure on the earth bonding. I'm not sure whether he means "oops" or "so long as no one has buggered about with it since I did it". Is this likely to be a cause of the corrosion? Notwithstanding other important reasons for bonding.
No, there was not a comparison test between the water from the deadleg against the supply. What was tested was the supply water from the well. Will suggest that he draws some water from a deadleg and get it tested.

Thanks for your help so far...

 

[R1CKY]

I've seen it once before. About 5 metres of dead leg, running surface mounted in a bedroom, just started weeping, turned out to be a pinhole. This was water from a mains supply in South Wales which is a soft water area.

 

[mountainman]

My comment about earth bonding was targeted towards whether electrolysis or electrolytic action could be involved.

As has been said, soft water can be aggressive and maybe a combination of factors will be to blame.