Sealing a weeping soldered pipe joint.

[chris French]

Arse - messing around with the CH/HW system plumbing and I seem to have managed to make a soldered pipe joint weep (presumably the joint was bit marginal and I forced it in a way that caused it to finally fail). I'm loathe to drain down enough so I can remake the joint right now as I recently put in some X400 cleaner and was planning on leaving it a bit longer before draining down anyway.

Any suggestions for something I could put on the joint for now that would seal it until I can do a proper job on it?

[The Natural Philosopher]

I've had partial success with ptfe tape covered with car body filler.

[fred]

In article , chris French writes

A few turns of self amalgamating tape[1] compressed by a jubilee clip over the leak to resist the pressure.

If no self amalg then a couple of turns of inner tube rubber (car or cycle) with jubillee clip will do.

[1] Correct application it to stretch it 30% as you apply it and it will bond to itself but it will need the clamp to resist pressure.

[chris French]

In message , fred writes

Ah, thanks, should have thought of something like that really :-)

I should have some self-amalgamating tape in the garage.

[Dave Liquorice]

You probably won't need to clamp it as well, good stretch when applying and decent overlap on each turn and well each side of the leak will be enough. I've use SA tape around the top hose on a car just on its own, CH isn't going to be anything like as hot or as high pressure.

[dennis]

Hmm...

CH pre pressured to about 1.5 bar rises to about 2 bar @ about 70C

Car radiator cap blows off at about 1 bar or less @ about 105C

I would drain it into a bucket, fix the leak and put the stuff back.

[Tricky Dicky]

Freeze the pipe either side of the weeping joint, cut out the joint and insert a repair joint which is like an extended straight compression coupling about 100mm long. Repair permanent and no draining down.

Richard

[Roger Chapman]

And if the CH works off a header tank ...

You will need a rather large bucket. When I have partially drained down my CH I used my redundant plastic rubbish bin and that wouldn't have been large enough for the whole system. Next time I will use a wheely bin but even then I doubt that that gives sufficient capacity for a complete drain down. Getting it back could prove interesting. I used an electric submersible pump and a garden house. Dennis will have to say how he would get his bucket full back into his pressurised system.

[dennis]

In a block of flats or a bungalow? It wouldn't be much of a problem to drain and refill from the bucket if it were a vented system.

What makes you think it all needs draining?

That's easy you use a pump. Do you think its difficult to do that?

[Roger Chapman]

Neither situation would result in a pressure rise when warmed up.

Just how much of the system would be accessible if you drained off just a bucket full? That wouldn't do much more than empty the header tank.

What makes you automatically jump to the wrong conclusion?

Do tell how you would do that. I will tell you how difficult I think it is once you say how. I don't have a pressurised system to experiment with.

[dennis]

How big is your bucket?

What makes you think your ch is anything like the OPs?

In that case you won't know how difficult/easy it is.

If you did have a pressurised system you would know its only pressurised once it above about 98% full, the (auto) vents are open to let the air out until you actually want to get the head up to 1.5 bar so you could fill it from a bucket with a syphon on the filling valve.

[Roger Chapman]

snip

I generally use 3 gallon buckets but I wouldn't want to climb a ladder into a loft with one anywhere near full or pour it into an open header tank with restricted access.

I was talking generally not having had an inside line to the op as you clearly think you had.

Maybe not but your description below doesn't seem to fit what little I know about pressurised systems, particularly those that have the filling loop permanently plumbed in.

[Andrew Gabriel]

At the Screwfix expo some weeks back, there was a company demoing and snap close repair cover for sealing around leaky joints like this. I don't seem to be able to find them on screwfix online.

[newshound]

I've had good permanent results with the epoxy putty which is made for this. This will stick on damp surfaces but you *might* have to drop the system pressure to ambient. If it is on a "warm" pipe and really is only a weep you might get away without depressurising. The nice thing about the putty is that you can apply it in tight spaces where it would be difficult to wrap with self amalgamating tape or to fit one of the repair systems.

[dennis]

Ah so you know lots that are not done legally? Just what is going to stop the rubbish in the system getting back into the mains water if there is a pressure drop, not just the "faulty" valves I hope. You disconnect the loop so there is an air break to be certain it can't suck the cr@p back in.

[Roger Chapman]

What makes you think I know of any personally? Fixed connections have been mentioned on this ng in the past.

As for your syphon you will have to explain how that would work since your solution would need both a negative head at the filling loop and a bucket sized void within the system.

[JonT]

[dennis]

Well if you have emptied a bucket out of the de-pressurised system there will be a bucket sized void in it. Full of air that will escape through the vents.

As for siphon I suggest you google for it.

If a siphon won't work you can go back to using a pump like I said the first time.

[newshound]

Don't modern hoses include a double check valve which, I suspect, is assumed to be sufficient without making a physical disconnection. Similarly a check valve is mandatory for garden hose taps.

[Roger Chapman]

Hardly a void since it is full of air. Air in the system will rise as far as it can but that still leaves the system with a considerable head of water. To expel the air that head needs to be overcome. You will not do that with a siphon unless you elevate your bucket above the level of the water in the system since siphons only work when the discharge end of the pipe is lower than the liquid level in the container being emptied.

Why? What would I learn if I did?

You know a siphon won't work. If it did you would be sure to tell me how.

Using a pump you still have to overcome the head in the system so you would need to plumb the pump in securely. Not exactly as simple as running a hose up to a header tank.