Shower connection problem

[jlacd]

I'm currently fitting a new shower in a 1200x800 recess. I've mounted the concealed mixer on a noggin on one of the short walls, and run a braided flexihose from the outlet, round the corner, to a central point on the long wall, where the sprayhead and rail will be. I'm currently sheeting up the long wall with 12mm Hardibacker, prior to tiling.

I'm struggling to figure out how to properly finish the pass-through of the feed to the threaded chrome "cap" type thing the shower hose itself screws onto - was provided with the shower rail/hose/head set. If I drill 20mm hole for the last compression joint after the flexihose - enough to get some thread through, with the depth of sheeting plus tiling - what's to stop the cap just spinning and pulling everything through? How do I keep it all properly located and tight?

Hope I'm explaining myself properly - it's kind of hard to describe. I think I'll post same message in decorating / tiling too - is it a plumbing or a tiling problem ?!?

 

[wanleg]

try some pictures to explain...

 

[jlacd]

Yeah, hard to explain, I know. I'll have another attempt - posting pictures looks like a lot of hassle (not having a public album on the web). Anyway.....

I have the 15mm flexihose running along a noggin in the stud-partition wall, the shower side of which is currently unsheeted. The flexihose is not flexi enough to make a 90 degree bend within the space of the wall, so it ends in a 90 degree pushfit elbow (A).

When the sheeting goes on, there obviously needs to be a hole in it so the feed for the shower can come through. If I make it a 15mm hole, and take a short length of pipe from elbow (A) through the sheeting, it will need another fitting (B) on *this* side of the sheet for the shower hose/elbow cap to screw onto. That obviously won't work, as the fitting B is thicker than thickness of tiles.

Alternatively, I could make a hole larger than 15mm, so fitting B sits within the depth of the sheeting, leaving just the required depth of thread sticking out (6mm tile +2mm adhesive +about 8mm thread = about 16mm). Aside from trying to get that kind of precision, it will mean (because the hole is greater than the size of the fitting B) that when I screw the shower hose/elbow onto it, it's simply going to pull fitting B through the hole towards me..... there's nothing behind the sheeting, attached to B, that is going to pull up against the back side of the sheeting. Imagine those old plasterboard fixings that have spring-loaded legs that pull up against the back of the board as you screw the thread.

Anyway, the result of that is a loose, not watertight fixing.

I'm looking for a way to get a tight connection through the sheeting / tiling, so that screwing on the shower feed / hose elbow pulls "something" up against the back of the sheeting.

Or do I just embed the fitting B into the sheeting with polyfilla and hope it dosen't pull through or turn as I screw the shower hose connector on? (YUK)

Wow. Long-winded, but I hope you get the idea?

Cheers

L

 

[namsag]

Don`t use a flexible hose if you cannot get access to it they are not designed for this and you will have to rip tiling out to get to it when it leaks use either copper or plastic water pipe .

 

[jlacd]

Eh?! Are we taking about the same thing - 15mm metal braided hose with chrome compression fittings? Never said anything about not using them behind wall on the packaging! Was the only thing that was going to go "round the bend" at 90 degrees through a 4x2. How prone are they to leaking?!?

 

[TicklyT]

A 15mm flexi hose will very likely only have about an 8mm effective bore. Some are as little as 6mm through the end fittings. That will greatly restrict the flow, giving a disappointing performance.

You would be much better off using 15mm copper or plastic plumbing, They have at least a 12mm bore. That's about 4 times the effective area of a flexi. Some showers even recommend 22mm connections. That's twice the capacity again.

You could use a wallplate elbow on the end of your pipe, mounted on the studwork.
e.g. http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=100122&ts=84218&id=17416 with a male iron nipple poking through the wall to connect to the shower fittings.

 

[jlacd]

All I can say is "oh b4lls". I thought the flexi hose was a great idea - I'd already tried to bend one of those flexible "concertina" type lengths of copper round, but it wouldn't go through the joist (it has to go through a 4x2 that has been drilled through two adjacent sides, so it's pretty sharp bend).

I'll check the bore, but might have to rip it out and rethink the run ..... would there be more pressure loss through the 1m flexihose, or would I lose more if I have to drop the feed from mixer down to the floor and up again - say 4m run with 6 90degree bends in 15mm pipe?

The stud-mounted elbow looks like what I need - thanks for that.

Cheers.

 

[jlacd]

Sodit - why make work for myself: I'll connect the whole lot up dry tonight, and see what the pressure at the shower head is like first!

 

[PilotPete]

Try one of these http://www.screwfix.com/app/sfd/cat...BGFUN0CSTHZOSFFA?cId=100122&ts=96053&id=23401 for your 90 bend which didn't work with a copper flexi. Alternatively, if your soldering is up to it (easy once you give it a go), try one of these http://www.screwfix.com/app/sfd/cat...BGFUN0CSTHZOSFFA?cId=100123&ts=96264&id=32367 they cost pennies and together with a length of 15mm copper pipe and a few simple tools will make your installation much better.

Good luck.

PP

 

[jlacd]

OK, checked the bore on the flexi, and ran up the shower - you're right: not as good pressure as before. Removed the flexi, "made space" for the compression fittings, and redid the run in plastic... that joist didn't look structural anyway

Still left with the question of how to keep everything tight. TicklyT - your stud-mounted elbow looks good, but my shower fitting is 15mm female, and that elbow is 1/2" - I've not seen any couplings that go one t'udder - 1/2" male to 15mm male. Somebody show me the way, or give me another idea

Cheers

L

 

[TicklyT]

Is your elbow designed with a tapered or parallel thread?

Most 15mm fittings use 1/2" BSP threads, so a 1/2" male nipple will usually marry the two together.

Wallplate adaptors will usually accept a tapered thread, and seal on the thread form with PTFE tape. This allows you to adjust the amount of tape you use, and how far you tighten it, so the fitting ends up pointing in the right direction when assembled.

Some fittings are designed with a parallel thread, and seal by clamping a soft washer between two flat faces, so you don't get so much choice about which way they point once assembled.


If you've got any odd compression pipe fittings around you could try one for size just to see if the threads match, or take the elbow with you to a plumbers' merchant (or even B&Q etc.) and check what bits will fit properly.