Cast Iron Heating pipe weeping

[darriusdax]

Hey guys, Unusual problem here, working on an old building where the heating pipes are cast iron, the general condition is good so I dont think this is a rip out and replace scenario. The problem is a small area on a pipe where there is no crack or visible hole, but water is slowly weeping through what must be a micro sized hole. I patched this about 2 years ago with.... dont laugh..... water proof sticks like **** followed by denzo wrapping. It worked but as I told them at the time it would probably only last a while and they would eventually need to properly repair it.The basic question is - does anyone know if it is possible to patch this or does it need a proper cast iron expert to cut a length out and replace.One repair i thought about would be a patch or rubber with 2 big jubilee clips ( the pipe is 3.5 inch)Any ideas would be great.Thanks.Nick.

Forgot to add, is Unibond epoxy metal repair an idea ? with the jubilee and rubber as a back up??

 

[stevetheplumber]

you can get mechanical couplings for cast iron though ive never used them on heating only on mains are you sure its cast rather than threaded steel got any pictures?

 

[SimonJohns]

Bss sell special clamp repair kits

I don't see how it's cast iron. Can you just cut. Unscrew and put a new peice in using a union?

 

[Chalked]

Bss sell special clamp repair kits

I don't see how it's cast iron. Can you just cut. Unscrew and put a new peice in using a union?

Plenty of large old heating systems done in cast with cement joints ( cement had the same expansion rate)
generally to fix you need to cut out the section, being careful not to disturb any joints. Then replace with a new piece of similar size steel with mechanical couplings.


EasiClamp
FEATURES & BENEFITS TECHNICAL SPECIFICATIONS
CUSTOMER BENEFITS


Can be installed underpressure -no costly mains shutdown, disruption to customers, dirty water complaints)-
Minimised health & safety risks to operatives
Available in three popular sizes DN80, DN100 & DN150
The 'waffle' design gasket is constructed in EPDM which is WRAS approved for use with potable water
Ensures a reliable seal with a working pressure of 16 bar and test pressure of 24 bar
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PRODUCT DESIGN BENEFITS


1. Corrosion Protection
All cast components are fully coated in Black Rilsan Nylon 11 which has excellent resistance to impact, abrasion, weathering and chemicals as well as good thermal stability and flexibility to accommodate for rough site handling

 

[darriusdax]

aye its definitely cast, and the problem is that the weeping spot is on one of the couplings, so a 3.5inch clamp wont fit. I will try a rubber patch with 2 large jubilee clips. Its a bodge but the leaking pipe is in a cupboard where noone will be offended by an uigly bodge, no reason why it cant hold for many years.

 

[Dotty]

is it leaking from the thread?

 

[happyflyer]

Send us a photo it will be better than text, greenhouse joint is what you need but if its in a confine space it may be difficult, Nick the ball tap washer and jubilee clip will do and see you out, it should last forever, the hole will be a sand hole in the original casting of the pipe, some old churches and some old schools still have cast iron, not many people around now who can do the joints.

 

[justlead1]

Hi Have a good look at the area leaking, perhaps grind a bit and find pin hole. Once found drill and tap then put a bolt in with some form of washer / sealant (you can now get bolt that drills and taps in one. Caulking with a bit of slate some times works as does iron filling mixed with a very small amount of cement (7:1) it was used of soil and drain cast iron, pressure was less of a problem

 

[happyflyer]

Justlead1,

Good suggestion, but it mean draining down, old system that could be a nightmare. the ball-tap washer and jubilee clip will see us all out, 10 min job. I went into the roof space of a University to trace some BMS cables and the 50mm copper HWS must have developed pinholes, about ever metre someone had put ball-washers and jubilee clips, the chap who did it was still there he had done this about 20 years before, not saying this is good practice but it worked.