PB or PEX

[Guitar_man]

Which one is best for central heating install and hot cold water piping, The difference seems to be 37.84-26.98 at toolstation for a 25m 15mm roll. Do you prefer one over the other and why?
Thanks in Advance,

 

[twgas]

Copper, copper, copper!!!!

 

[Guitar_man]

lol, too damn expensive!

 

[Agile]

The tube may be a little cheaper in plastic but fittings are about three times that of copper endfeed.

And the performance of copper far exceeds plastic.

Seems you want a DIYer's bodge installation.

Tony

 

[Guitar_man]

On the contrary, plastic has many advantages.
Doesn't rust, doesn't condense, flexible, less joins required, vastly shorter fitting time so lower labour cost, lower parts cost, similar lifespan, easier servicing to name but a few. I wouldn't call that a bodge at all.

 

[Dan Robinson]

Does copper rust?

 

[Guitar_man]

Seen a few ghastly looking green installs over time.
Anyway let's not make this a copper versus plastic debate!

 

[SandyLyon]

On the contrary, plastic has many advantages.
Doesn't rust, doesn't condense, flexible, less joins required, vastly shorter fitting time so lower labour cost, lower parts cost, similar lifespan, easier servicing to name but a few. I wouldn't call that a bodge at all.

You missed a few out.

Cooler to the touch,
Quieter in service (expansion / contraction) on Central Heating
No lime scale build up in Hard water areas
Can use in Soft water areas where copper corrodes
No scrap value
Up tp 50 year warranty
No Hot Works
Comes in coils so less wastage.
Less likely to burst due to freezing

Always PB more flexible and easier to work with.

 

[SandyLyon]

No it doesn't rust, but I worked in an area of the Lake District near Coniston with very Soft water and the copper pipe was only lasting a few years before corroding and perforating. The cylinders lasted a little longer due to them having a sacrificial anode

 

[Agile]

Water can be dosed with whatever you like.

Copper is not chewed by rodents!

Copper withstands at least 250 C ( which melts the joint solder ).

Copper does not sag.

Copper can be removed and reused elsewhere.

Copper has a scrap value which can be reclaimed at any time in the future.

 

[SandyLyon]

Water can be dosed with whatever you like.

Copper is not chewed by rodents!

Copper withstands at least 250 C ( which melts the joint solder ).

Copper does not sag.

Copper can be removed and reused elsewhere.

Copper has a scrap value which can be reclaimed at any time in the future.

Tony,

Both products have their merits, all visible pipework in my own house is copper, radiator tails, boiler and cylinder cupboard etc.

Water can be dosed with whatever you like. - yes you can, you can also dose plastic within the guidelines.

Copper is not chewed by rodents! - Rodents also will chew through electric cables etc, there is nothing in the material that attracts them. If there is a big rodent problem I would a) use copper and b) advise them to get Rentokill in.

Copper withstands at least 250 C ( which melts the joint solder ). - Plastic has it's limitations and has strict guidelines where it shouldn't be used (gas, oil, compressed air, steam) and is ok up to a short malfunction temperature of 118 deg c at 3 bar. Seeing some boilers are set at 82 deg c max (condensing boilers less) temperature shouldn't be an issue.

Copper does not sag. - if surface fixed use copper or trunking.

Copper can be removed and reused elsewhere. - So can plastic

Copper has a scrap value which can be reclaimed at any time in the future. - Exactly but not always by legit persons, metal thefts are a major problem

 

[Agile]

Plastic has it's limitations and has strict guidelines where it shouldn't be used (gas, oil, compressed air, steam) and is ok up to a short malfunction temperature of 118 deg c at 3 bar. Seeing some boilers are set at 82 deg c max (condensing boilers less) temperature shouldn't be an issue.

The temperature limitation of plastic does become an issue when there is a boiler malfunction.

There was a posting I think on this forum several years ago when an installer had fitted a sealed system conversion to the older c.i. boiler and used plastic pipe.

The boiler overheated and the plastic pipe burst in the loft and brought down the ceiling and did about £3500 of damage.

The installer blamed the boiler maker because the conversion had not turned the boiler off before the temperature got so high the plastic burst.

He lost all the arguments and was held responsible for paying for all the damage. He could not see what he had done wrong!

It makes interesting reading if you can search for it !

Tony

 

[SandyLyon]

I am aware of a few instances of similar happening, it's usually been on older boilers or going back about 10/12 years a contract boiler was launched that had very basic controls.
That boiler manufacturer added number of safety features, off memory it was a new modified H/L stat and a pump over run.
Also different manufacturers will stipulate that the first 1m, 2m or 3m should be in copper.

 

[Guitar_man]

Always PB more flexible and easier to work with.

Thanks,
I did a little google, and came up with this, seems like PEX is better in high pressure installations.
http://www.pexmall.com/difference-beetwen-pex-and-pb-pipe

I spoke to a mate today who advised that the limiting lifespan of plastic is the Orings in the joins, over time they go hard and leak. Not sure how long this is but of the order of 10years.
I suspect that the PEX is also more difficult to straighten out if you buy it on a coil, there are a few comments to this effect on toolstations website,though i have not used it myself hence the question.
Cheers,