Joining galvanised conduit

[securespark]

In my view Conlock does not replace the real thing but it has some very good benefits. One of which is avoiding running couplers.

They were the fun part of conduit installation!

 

[pete01]

What's the big deal with a running coupler?

 

[Harry Bloomfield]

What's the big deal with a running coupler?

They needed a lot of effort, to cut the very long thread. The length of thread, needed to be as long as a coupling, plus a locknut, plus a bit for luck.

 

[pete01]

They needed a lot of effort, to cut the very long thread. The length of thread, needed to be as long as a coupling, plus a locknut, plus a bit for luck.

I know what one is I just dont see the big deal, just keep turning until its threaded enough

 

[JohnW2]

They were the fun part of conduit installation!

I've often sat in places like schools, hospitals, public buildings etc. looking at the (often large bore) 'iron'/steel plumbing, all seemingly held together with screwed joints, and have wondered how on earth it can be maintained non-destructively without dismantling the entire installation. It's all very well installing it in the first place, since one can start at one end of a pipe run and progressively screw things together until one gets to the other end - but what if one wants/needs to undo some connection in mid run (e.g. to replace a valve, radiator or whatever)?

Any approach I can think of would involve a hacksaw or grinder

 

[plugwash]

I think radiator valves usually have a union connection between the radiator "tail" and the valve. So you can undo the nut and the radiator seperates from it's valves. Having seperated the valve from the radiator you can then unscrew it from the pipe (you may have to remove some pipe fixings to give you enough wiggle room).

If you need to replace a component that is installed inline in a pipe run, I think you would have to cut the pipe, unless there is an existing union you can take apart. Then add a union to rejoin it.

 

[JohnW2]

I think radiator valves usually have a union connection between the radiator "tail" and the valve. So you can undo the nut and the radiator seperates from it's valves. Having seperated the valve from the radiator you can then unscrew it from the pipe (you may have to remove some pipe fixings to give you enough wiggle room).

Yes, that may be true of a rad, but some components (like in-line valves) look as if they have simply been 'screwed on' to the pipes?

If you need to replace a component that is installed inline in a pipe run, I think you would have to cut the pipe, unless there is an existing union you can take apart. Then add a union to rejoin it.

How does this 'adding a union to rejoin it work' (if the pipes, when cut, cannot be rotated and have no 'slack')? What sort of 'union'?

 

[plugwash]

Afaict (I am not a plumber) a union has three parts, a male and female cone that screw onto the end of the pipes and then a locknut that clamps them together.

RS PRO Stainless Steel Pipe Fitting, Straight Octagon Union, Female G 1/2in x Female G 1/2in | RS

uk.rs-online.com

I suspect in most cases there is enough play in the pipes to "pop" things together with a single union but if not then using multiple unions would seem to be an option..

 

[JohnW2]

Afaict (I am not a plumber) a union has three parts, a male and female cone that screw onto the end of the pipes and then a locknut that clamps them together.

RS PRO Stainless Steel Pipe Fitting, Straight Octagon Union, Female G 1/2in x Female G 1/2in | RS

uk.rs-online.com

OK, but is there not still a need for some slack in the pipes to 'get it in'? One really needs a 'slip' fitting of some sort.

I suspect in most cases there is enough play in the pipes to "pop" things together with a single union ....

Not, I suspect, in the sort of pipework I'm thinking of - not uncommonly around 2" OD, with 90° elbows and often emerging through 'tight holes' in floors and/or ceilings.

 

[Harry Bloomfield]

OK, but is there not still a need for some slack in the pipes to 'get it in'? One really needs a 'slip' fitting of some sort.

The cone takes care of that, they just need to be able to be sprung apart, a few mm, to get the cone out of the cone socket.

 

[trojanhawrs]

You're right john, often a complete section needs to be made up when these go. VJ couplings are often used where the pipe needs to be cut back and you've got no give, needs to be well supported either side though because the rubbers shouldn't be bearing weight of the pipework

 

[JohnW2]

The cone takes care of that, they just need to be able to be sprung apart, a few mm, to get the cone out of the cone socket.

I suppose I might be wrong, but I rather doubt that even "a few mm" of 'sprung slack' is available in the sort of pipework ('built like a battleship') I'm talking about!