Pinholed copper pipe - how much to replace?

No. Remove just enough so you can easily insert and secure a couple of straight connectors.

Might be worth investigating what caused the puncture in the first place?

Daljit

Thanks Daljit

There was no evidence of _external_ damage to the pipe and AFAIK nothing in the insulating sleave that could have worn a hole in the pipe. What concerns me is the possibility that the whole section is partially perforated throughout it's length - but then that could equally apply to all the pipe that BG used, couldn't it? Happy thought, no? ;-)

Richard

It sounds like it had impurities in the copper, possibly iron. This was common in an earlier period of poor quality copper tube turning up in a number of places. I wouldn't be at all surprised if that length of tube failed again at some point.

A-ha. But where would be a sensible place to stop? With that length? Surrounding pipes?

Daljit

If it was mine I would replace the whole section at the very least. What about the rest of the installation though? As Daljit says, where does one stop? Or can BG be persuaded to accept any responsibility. Andy has 5* cover which seems to mean that they fix anything to do with the CH system, but would that include pipework and consequential damage?

Richard

Usually erosion, downstream of fittings, but there shouldn't be any flow into a CH F&E tank, should there?

Where is this? I've heard of erosion problems with water drawn from deep bore holes (Bromley, ISTR). Is/was a water softener involved?

Probably just one bad component.

You could go to a sealed system if the boiler is suitable. On fit a low water cut-off on the F&E tank and isolate the mains water supply. Many heating systems had no make-up connection originally.

Indeed. It was static water within the feed pipe to the ball c*ck controlled top-up to the CH header tank

Bromley/Bellingham boder

Nope

I hope so!

I doubt that funds will be forthcoming for such a change

On fit a

Mm. It's a thought.

Ta

Richard

supply.

VERY interesting. I had an incident last year in one of my rented flat in Bromley South where pipes were pinholed, but these were installed just post war in a 1950's bomb damage replacement shop block, heavy (by present day standards) walled 1/2" pipe. So what is the mechanism?

AWEM

I worked for the ILEA once upon a time. They had issued an engineering note about corrosive water causing problems with copper pipes in school properties in the Bromley area. I have it in my library (the loft), somewhere. ISTR stainless tube was mentioned. I'd have to dig it out. The water supplier would probably have more details.

Most strange; the one area I'd heard of this, in the entire UK, is near where this should be.

Is the flat fed with softened water from the launderette?

installed

heavy

mechanism?

No, it's got it's own mains feed and header tank, and the water is pretty hard. The tank is (grimace) still the original galvanised steel one and I had wondered if there was some electrolytic reaction, but the pinholes (there were 3 or 4 iirc) were quite a long way down the run of pipe in a horizontal section.

AWEM

"Richard" wrote

Neighbours of mine recently suffered similar leaks. Theres were due to mortar having been splashed on the pipe during construction of the house 35 years ago. This had eaten through their rising main and cause a couple of small holes. Fortunately it was within boxwork and they heard the hissing noise as the water hit the inside of the plaster box

Phil

I have read that US practice when plumbing dissimilar metals does avoid electrolytic action, by breaking the plumbing joint with a non-conducting insulator.

BTW: We had a sudden rash of pinholes in the h/w tank and a failure of the cold tap nearest the rising main. The beautiful salmon pink inside the tank and the suspiciously clean innards of the tap made me suspect something incoming had caused etching of the copper. In our case I suspected the disinfecting chemicals they regularly dose into the reservoir.

I've had a rummage. It says this.

"Corrosive Water from Bexley Wells Sites that fall within the following general areas may be fed with mains water originating from wells in Bexley. This water is extremely corrosive due to the high concentration of dissolved CO-(approximately

So it seems you are, or were, getting naturally sparkling mineral water. Points to note about the above; It dates from about 1987, so things may have changed. Thames Water may have fitted de-gasification plant or the Bexley well water may now be diluted by supplies from elsewhere. Thames Water should be able to tell you. If it's still going on, it should be common knowledge in the plumbers' merchants in the affected areas.

Aluminium sacrificial anodes are now verboten. Most commercial stainless steel water heaters come with an electronic gizmo that does away with the need for sacrificial anodes.

LSS was the GLC/ILEA's in-house chemical consultants, they were good ISTR. I think they had a management buy out when Heseltine killed off the GLC/ILEA for incorrect pinko-leftiness.

Ignore the specification for stainless; use PEX plastic. It wasn't available then.

Heated & vented water pipes (DHWS & LTHW) weren't at risk because the CO2 comes out of solution on heating.

Should be dissolved CO2. I'd scanned it.

CO-(approximately

..ho - ho that could account for the milk in the coconut !

AWEM

In cars with aluminium heads and iron blocks, this is why anti-freeze is a must. It inhibits electrolytic corrosion

anti-freeze

Not a lot of good for drinking water though (unless you are making Italian wine )

AWEM

That was the Austrians. At least it was they who were caught.