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Plastic Pipe Supply for shower 15mm or 22mm (Read 15953 times)
bevo
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Plastic Pipe Supply for shower 15mm or 22mm
Nov 10th, 2007, 6:02pm
 
I am installing a normal thermostatic mixer shower on an unvented system.
I have read that the pipe inserts in plastic pipe reduce the pipe diameter in 15mm pipe to about 10mm. Would this affect the pressure of the shower?
Would I be best using 22mm pipe if I use plastic as this would probably be about 15mm internal diameter.
I only want to use plastic under the floor boards and go back to copper for the final feed to the shower as it would be a lot easier than trying to use copper under the floor. Should I use 22mm plastic and a reducer to 15mm copper for the final feed to the shower?
What do you all think??
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thescruff
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Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #1 - Nov 10th, 2007, 6:12pm
 
The answer depends on the pressure, what it can deliver and more importantly what the shower valve spec is.

I'm not a lover of plastic pipe in and size shape or for, and although it has its uses I would always use compresion fittings where it not accessable.

The inserts will make no difference to the flow, but plastic pipe is considerably thicker than copper, so the bore will be smaller.
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Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #2 - Nov 10th, 2007, 7:46pm
 
Copper all the way!

Good practice running it under the floor!

Working as a spark, I have seen several push fits blow apart when being on site when plumbers are filling a system.  Isn't there also a poor guarantee on push fits?
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bevo
Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #3 - Nov 10th, 2007, 9:05pm
 
Ok guys, I admit defeat. I will try and do it in copper.

The plastic would be accessible as I was going to only use push fit fittings when the pipe had come through the floor under the shower tray (which is raised up to allow access) and in the wall where there would be an access panel with isolation valves.
It is hard to know who to believe. I have read about people who swear by push fit like speedfit and other people who ony trust copper and soldered joints. Has anyone else got any opinions?

On another issue my stopcock has started leaking because of turning it off and on. The leak is comong from around the tap spindle. If I shut of the water supply by closing the stopcock can I re-pack the gland nut to stop this leak while the water is still on from the supply?
The reason I ask is I can't see a stopcock in the street. I have a severn trent water meter that has a disk in the body of the meter that says "on". Do some meters have a built in valve to shut off the supply instead of a stopcock in the street?
Regards, Bevo
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thescruff
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Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #4 - Nov 10th, 2007, 10:18pm
 
You miss read my post Bevo.

Use plastic by all means but use compression fittings instead of the plastic rubbish, but stick with copper for any surface work.

Just one thing to remember though, if you suffer from vermin at any time especially under ground floor floors then use copper.

The stopcock you can re-pack with a couple of turns of Loctite 55 string, just undo the gland nut and wind it around the spindle and push it in.

The outside meter will have a little plastic sq which should have a plastic stick about 200mm long.

`warning they can be a Bin Laden to turn back on as they do stick.
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bevo
Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #5 - Nov 10th, 2007, 10:30pm
 
Hello thescruff,
sorry for being a donkey but do you mean use metal compression fittings on the plastic pipe????? instead of the push fit fittings.

Regarding the stopcock can I wind the tap in so the supply to the house is off, but the mains supply from the street is still on and then undo the gland nut without water shooting out everywhere?

Can you explain a bit more about the meter. When you say it should have a plastic sq what do you mean?? I work in computers. Perhaps I should stick to what I know and get a plumber in!!!
I only want to do this myself as I like learning new stuff.
I'd better check my house insurance to see if it covers a computer idiot flooding the house!!!!!
Thanks fo your replies though. It is good to get advice from people who actually know what they are doing!!!!!

Cheers, Bevo
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Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #6 - Nov 10th, 2007, 11:05pm
 
Must be very cramped in a computer or are they big ones  Grin

yes I mean brass compression fittings, you still need the inserts though.

The stopcock you turn off first then undo the gland nut, the little brass bit under the handle, you may have to move it back and forward to free it up.

The outside jobbies you clearly see the plastic square knob would normally be white.

If you have a problem post a pic looking down on the water meter.
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bevo
Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #7 - Nov 10th, 2007, 11:32pm
 
Hello thescruff, good job these computer things are more intelligent than me. Perhaps I could get some software to plan my plumbing for me! and a robot to install it!!

I will perhaps post a picture of the water meter if I can't see the off switch.

I read some advice that some people have packed the gland nut with the water supply on. I didn't understand from your last post as to whether I do need to turn the water off in the street to do this. Can you advise??

Thanks for sticking with me with the advice. At least I can give you a laugh at my inexperience!!!!

Cheers, Bevo
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Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #8 - Nov 11th, 2007, 1:49am
 
You should just need to turn the inside stopcock off.

Open the nearest tap and take the back pressure off the valve and providing the valve holds you should be able to work away at your leisure.

I would not expect it to be a problem but its alway handy to know you have another option for future use.
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JerryD
Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #9 - Nov 11th, 2007, 7:22am
 
Now, just to throw a spanner in the works.......

I use plastic pipe and fittings a lot.  On 15mm I use PolyPlumb and on 22mm I use Speedfit or PolyPlumb.

The PolyPlumb pipe inserts are stainless steel so very thin and have no effect on water flow.  The Speedfit inserts are plastic and quite chunky but I like the ability to 'undo' the Speedfit fittings.

Speedfit have changed the design of the fittings and now you can lock them shut by twisting the 'nut' on the fitting and you can even fit a collar between the nut and the end as added security if you want.  Old Speedfit fittings could come apart if the collar was pushed against something (a stud frame for example).

I've never had a fitting fail although I had one leak once.  This was due to the plastic pipe being badly scratched where we dragged it through a hole drilled in a wall.  The O ring couldn't make a perfect seal on the scored pipe.

I like the way plastic pipe fittings can rotate so avoiding the twisting torque you get with compression fittings.  They are also extremely quick to fit.

Plastic pipe also eliminates the need to supplementary bond the pipework in a bathroom.  I always use copper for the last bit up to the rad or towel rail (just for appearance sake).

The 22mm Speedfit I now buy in 3m straight lengths as the 50m coils do NOT want to straighten out!

So I now buy much less copper than I used to.  Plastic pipe is more resistant to freezing as it will not split (we all know copper will) although this does not mean you don't need to lag it!

Never mix 'n match makes.  If you want to join Speedfit to PolyPlumb or to Hep2o then use a short length of copper between as they are all compatable with copper.  Alternatively use a brass compression fitting to join them.   Smiley
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Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #10 - Nov 11th, 2007, 9:56am
 
Typical builder  Grin Grin  Chuckitin&Leggit  Grin Grin

This was due to the plastic pipe being badly scratched where we dragged it through a hole drilled in a wall

Good plumbers  Cool and DIYers always sleeve the pipe through the wall  Roll Eyes

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JerryD
Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #11 - Nov 11th, 2007, 10:13am
 
:-D  Yes but we can build the wall in the first place!  :-D

Tongue
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Andyco11
Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #12 - Nov 11th, 2007, 10:31am
 
Quote:

Can you explain a bit more about the meter. When you say it should have a plastic sq what do you mean??
Cheers, Bevo



Just for info my meter is the stopcock.
i have to turn the whole meter about 3/4 of a turn to kill the supply to the house.
and it was a real pain as the first time i tried to turn of the water the meter was so far down the hole that a couldn't reach it so i had to dig up the street to turn it of and then it still took 30 mins of grunting to turn it.

so i fitted one of these
...

And boy has it saved my bacon alredy as when we had a burst (an old compression fitting on the cellar) instead of taking 20 -30 mains to turn of the mains in the street again i just flicked the switch and of went the water
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bevo
Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #13 - Nov 11th, 2007, 11:44am
 
Hello guys, thanks for all the good advice.
I fixed the stopcock this morning thanks to thescruff's advice. Cheers.
I only had ptfe tape not the loctite string but this worked great.

I think I am going to try and use copper all the way for the pipework.
I only have a short run to do and I have read some other horror stories.
Some people jointed copper to plastic with a compression fitting but as copper and plastic expand at different rates this caused issues and the joints leaked.

Nice to see we have some friendly banter between the plumbers and the builders!!!! No fighting now gents!!!

Seriously, thanks for the help and I will let you know if I manage to do the pipework as this is my first attempt at soldering copper. I might try solder ring instead if end feed as I assume this is a bit easier.
Regards,
Bevo
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Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #14 - Nov 11th, 2007, 12:07pm
 
Strange as it may seem an end feed fitting is less likely to leak than a soldering fitting.

Clean the pipe and fitting, and apply Laco flux with a small brush to the pipe only.

Push together ad apply heat to the fitting, if you look closely you will see a slight change of colour, remove heat and the solder should melt into the joint if hot enough, otherwise add more heat.

Do not melt the solder with the blowlamp, but let the pipe and fitting do it, that way you know the fitting is hot enough without blackening it, try it on an offcut in the garage first.

When cool wipe with a damp cloth to remove an excess flux.
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bevo
Re: Plastic Pipe Supply for shower 15mm or 22mm
Reply #15 - Nov 11th, 2007, 12:21pm
 
Thanks thescruff, great advice. I am going to buy the suff and have a go!!!!!!!!!!
Cheers, Bevo
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