One of those weekends... plumbing

[David Hearn]

Long story cut short.

Got a BIG problem...

Decided to replace rad valves with TRVs. The 2 drain c**ks were scaled up and leaking. Replaced them using compression T's with screw in drain c*ck (previously inline drains). Also had used a compression coupling due to the difference in lengths of old and new. When doing up either coupling or T, noticed pipe rotated as was tightening. Thought it was bad. After finishing and refilling noticed the next T (compression) under the middle of the living room floor is now leaking badly. What's the chance I just need to tighten up the T joint that's leaking? How do I stop the pipe from rotating as you are tightening?

Also a lot of the radiator valve tails are leaking (the ones which go down to the floor). I suspect its down to me using new olives where (or near) old ones had been. What should I do about this then? Should I cut off where the old olives go? If so, I then need to lengthen the pipe.... without having a blowtorch I can't do solder fittings, which means I can't do 'nice' joins (ie. where visible - ie. for extending the tail). Incidentally, the whole reason I'm doing the work now is because we were left with a weeping solder joint on a radiator tail!

After 2 days work I now have a leaking central heating system and the dread that I've got to replace most of the radiator tails to stop them from leaking....

Please - suggestions on how to sort out this mess, and preferably a nice easy way!

Thanks

D

[Dave Plowman]

You don't need an expensive blowlamp to do capillary joints - a tenner should be enough. And you'd save that in the cost of the fittings. Done with a little care, a soldered joint never leaks.

[Mungo Henning]

If anyone doubt me I can send them some brass bits: I have (to my absolute horror) found different compression fittings with different threads.

I found this out to my cost when performing some acrobatic contortion in at the eaves of the roof whilst plumbing. When the old compression nut didn't hand tighten further than a single turn my lazy mind decided to use the water-pump pliers.

Tightenened up style-A nut onto a style-B compression body and then I found that the joint leaked. About an hour or so later I decided to cut my losses and replace the section with a nut and body bought together.

So please take care - there are some older compression joints out there with a different thread pitch than "usual". Check that the new component's nut fits on the old body that you have disconnected just to be sure.

HTH

Mungo

[Set Square]

You're absolutely right that not all compression fittings have interchangeable bits - but a lot *do*. For instance, I recently changed the gate valves on my pump - and the new valves fitted straight onto the pipes, using the old olives and nuts.

You will note that I asked a question about whether the old nuts would have fitted the new fittings - rather than stating categorically that they would. The OP might well have come back and said they didn't fit - but I suspect that he hadn't even considered it.

[Ed Sirett]

Yep. The threads on most 15mm compression fittings are standard 1/2" BSP.

Some older stop valves, and some other fittings especially with 8 sided nuts seem to be different.

With the 22 mm none of the threads seem to be 3/4" BSP. Mostly the threads seem to be interchangeable except for motorized valves which have a very fine thread and again some older fittings with 8 sided nuts.

[Phil Addison]

I know Boss White is theoretically not required on new, well aligned joints, but I find that it's lubricating properties allows the joint to be smoothly tightened up without that awful screech and sudden stop that sometimes occurs when dry assembled parts gall (cold weld) together. I now always smear a very light trace of Boss White over the olive mating surfaces (not the threads).

To get the water out, cut the pipe and re-join it with a straight coupler (For other's benefit, Ed, I know you know this).

Possibly, but surely better to disassemble, clean, and start over? In this case the trusty Drayton Drain Plugs allow you to disconnect a joint without draining down, and you loose only 1/4 pint of water.

-- Phil Addison The uk.d-i-y FAQ is at

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[Dave Plowman]

I tried the 'new' Fernox jointing compound the other day - it appears to be some form of silicone by the smell. Can't really say if it worked or not, but I'd no leaks out of about 20 joints.

[Set Square]

In

What are these? Are they the bungs with which you block up the feed and vent pipes?

[Ed Sirett]

Yep they are conical on one end for jamming into the tank outlet from inside and the other end fits over both 15 and 22mm pipe to seal the vent. Although a speedfit end stop would be OK. It is amazing how little water comes out after plugging. Golden rule is always work on one joint at a time, and if possible close of a nearby valve on one side of the joint as well.

[Phil Addison]

That is because if you have two open joints air will enter the higher one allowing water between it and the lower one to drain out. Water will be retained only above the highest opening. However, I have had some success removing both valves to a radiator where both openings are on the same level, but you do that at your own risk!

Phil Addison The uk.d-i-y FAQ is at

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[njf]

Hummm, I prefer to put a little lube the threads as well, though years of using expensive stainless fittings (Swagelok) that will gall the threads if the silver plating is damaged/worn away is probably why, on those a little lube can save a lot of future time/cost.

Niel.

[Peter Andrews]

though I'm daft... (well perhaps they are right!).

Peter

[Dave Plowman]

Tried the sheds? Got mine in B&Q, but some time ago.

[Phil Addison]

Got mine from B&Q 3-4 years ago. Try [e-mail], or Website:

they own them now.

This is Drain Easy data sheet

Phil Addison The uk.d-i-y FAQ is at NOSPAM from address to reply