Pex pipe and combi

[lancenotalot]

Will be piping up my loft extension soon for ch and wanted to use pex pipe.Have someone coming to fit a combi for me once the pipe work is in place.My tutor at college mentioned about having to have copper from the boiler to start with then connect to the pex.

I've lost my notes and can't remember the distance in copper.Can any of you guys remind me please?

 

[glasgowgas]

it tells you in your boiler MIs

 

[Agile]

Its usually 1m.

But didn't your college teach you how to do copper pipework?

In any case why are you not asking the gas registered installer you say is coming ???

Tony

 

[lancenotalot]

Yes have done copper at college and at our old house but have been told by a couple of plumbers that plastic is both cheaper,quicker and less mess (no soldering) to install.

Haven't picked a boiler yet so can't refer to MI.

Just asked installer if I got pipework ready and tested would he connect up the boiler.Don't really want to call and ask him but I suppose I should to be sure.

I'm thinking now that this post should really have been "should I use plastic?"

 

[neds]

Any DIY monkey can put some pushfit together, yes its cheaper and quicker but any self respecting plumber would not choose this over copper if it can be avoided. At least you are using barrier pipe so doing something right!

 

[russella]

If it's any use, I'll add my massively inexperienced perspective on this one.

I've got a combi boiler setup, and I've just repiped all of my downstairs rads in plastic - 22mm JG Speedfit, with pushfit reducing tees and 15mm pipe coming up under each rad. Compression fitting joins the upstairs pipe to the plastic. In short, the install was an absolute doddle - took me a morning to run most of the pipe, and probably a day's work to connect up the rads and test everything.

However, when I did a similar job upstairs, I did NOT use plastic - I used copper. There were three reasons why:

1. Would struggle to get plastic to bend through some of the tight spaces that copper has bent nice and neatly using a pipe bender

2. If the joints fail upstairs, I've flooded all my ceilings. If the joints fail downstairs, I've just got a damp concrete crawlspace to deal with.

3. I kept a lot of the existing pipework upstairs, and didn't like the idea of mixing plastic and copper so much.

So my thoughts would be if you're going to use plastic in a loft conversion, might be worth looking at using compression fittings so there's less chance of a fitting blowing off? At worst you'll get a slow leak which you can find and fix before it does too much damage.

PS - I think it's recommended a MINIMUM of 1m copper from the boiler unless your boiler manual says otherwise - but I've erred on the side of caution and used around 2m.

Russ

 

[fazedup71]

I would use copper, plastic is for DIY and is very amateurish to say the least. If you have been to collage why are you messing around with plastic?

You should try moving a plastic joint in a few years time, you can swivel them round when they are new but after a few years that kind of movement will create a leak.

Having tried to power flush the stuff and failed!! I wouldn't touch it! We did 4 or 5 on an estate with faulty mains feed cylinders, ended up cutting a lot of it out

 

[russella]

I would use copper, plastic is for DIY and is very amateurish to say the least

Not meaning to have a dig at anyone on here, but this kind of statement is a little irritating - quite often I've seen plastic dismissed on here just "because it's plastic" and there seems to be a resentment because it's too easy? (Which of course it is)

You should try moving a plastic joint in a few years time, you can swivel them round when they are new but after a few years that kind of movement will create a leak.

That however is a fair point - and the reason why I didn't use it upstairs. Is there a specific brand you've worked with when you say this?

Russ

 

[fazedup71]

i had to alter some Hepworth in a fairly new build, lets just say things got moist! I don't like the idea of the o ring, we all know o rings go hard and start to letby, plus it really can be come blocked if the system is ever allowed to get in a mess

 

[neds]

What really irritates me is how the plastic manufactures can give the massively long guarantees for these pipes when they haven't even been around for that long!

 

[tamz]

What really irritates me is how the plastic manufactures can give the massively long guarantees for these pipes when they haven't even been around for that long!

It has been around since the late 70's. First one i remember was the Bartol Acorn (the brown stuff). Never come across much of that anymore.
It has its uses and every plumber will use it at some time because it is easier or to pull them out a hole but generally, for anyone with a bit of pride in what they do, it is a last resort. Shyte.
It is used on new builds all the time tho.

I would use copper, plastic is for DIY and is very amateurish to say the least

Not meaning to have a dig at anyone on here, but this kind of statement is a little irritating - quite often I've seen plastic dismissed on here just "because it's plastic" and there seems to be a resentment because it's too easy? (Which of course it is)

Russ you have stated in your previous post just how confident you are with having plastic. Yes it is easier to fit, infact simple but you still don't trust it upstairs? If it leaks it is usually a flood.

The only plastic worth a shout is MLC which is good stuff. Have a look at this
http://www.pexgol.ru/support/Articles/multilayer-pipes.pdf
Unipipe is the most common but that link will give a better idea.

Here is a Unipipe link too for anyone who might be interested
http://www.uponorhousingsolutions.co.uk/