Plastic pipe connections ... everywhere

Fredser

Gweetings

Had a plumbing guy give me an estimate for a new central heating system I want installed in a house of mine (the asbestos laden one!!).

He reckons he can use plastic pipe and push-fittings all over including the connections to cylinder and storage tank? I have never seen plastic pipes connected to a cylinder or storage tank before...

Any ideas?

F

rooferPete

Hi Fredser,

The Qualpex pipe has a very high temperature rating, I think about 80 degrees and can be used direct from the cylinder.

He has to come off the boiler in copper for at least 2 metres (I think), make sure the pipe and the fittings are marked Qualpex, there is some very strange plastic turning up with zero standards.

Depending on the system he may have to run copper to the coil in the cylinder.

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gregos

Qualpex plastic pipe is fine for heating. There's an absolutely superb system called Unipipe, about 20% dearer but with fittings as good as Tectite, and bendable by hand. Swedish as far as I know.

GreeBo

Once you go Qualpex you will never go back.
Damn you copper, Damn you!
Lets not even mention Gun Barrel /me shudders

Wobs

Unipipe is availble here from Unipipe.ie. They are based out in Bray. Their main business is Geothermal and Underfloor heating. The pipe has a metal core which acts as the diffusion barrier and which makes it bendable by hand and keeps its shape. I reckon I will be specifing this pipe to my plumber!

Fredser

General question regarding the use of copper and qualpex...

Can brass compression fittings be used with qualpex once a brass insert is used or will a plastic insert do here also?

rooferPete

Hi Fredser,

The insert used to be brass, Qualpex changed them to plastic and compression fittings is what they were designed for.

Qualpex upgraded a while back and have a reinforcment that helps with the bends and the Tectite fittings work wit Qualpex as well.

Tectite are an expensive fitting, try and stay with the plastic or standard brass (Conex) fittings.

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Fredser

Thanks for the swift reply Pete

Just keeping my plumber guy on his toes!! He said he was going to use plastic inserts with brass compression fittings and I nearly fainted!! ... but as you say all seems ok with that.

It shows its a while since I did DIY plumbing becuase I remember driving for miles looking for brass inserts for my DA because he kept shouting that the plastic ones were useless etc...

Cheers

F

flocker

Fredser,

if the cylinder is going to be piped using qualpex, make sure that the plumber clips the pipework securely and regularly.

I think it's still hard to beat copper in places where you can see it ( hot press, up to rads etc). It doesn't take that much longer, the materials are cheaper (soldered fittings) and it looks tidier. Leave the plastic for joists and roof spaces.

Most boilers have to be piped away from them in copper. Plastic isn't suitable.

antoinolachtnai

Plastic is actually pretty strong, maybe even a little more rigid than the copper one.

It's the guys who couldn't be bothered using inserts at all that you have to watch out for ...

This is just my opinion, but it sometimes seems to me that Qual-pex is the Visual Basic of plumbing. It's a fantastic material, and it makes it easy, but maybe it makes it a bit too easy. It might make someone think that it's easier to throw in a system than it actually is. Planning a heating system is still a serious undertaking that needs to be done by someone with real experience. I'm sure your plumer is excellent, but you're dead right to keep tabs ... you need to be happy that the guy knows how to set up the expansion tanks properly, and if there's gas involved ... well, you can guess what I was going to say next.

flocker

Plastic is actually pretty strong, maybe even a little more rigid than the copper one

Can't agree with this

Planning a heating system is still a serious undertaking that needs to be done by someone with real experience.

Do agree with this

Lex Luthor

I worked for a large equipment manufacturer before that supplied machinery to the semiconductor industry and the large machine they supplied over here had a water cooling system on it simlar to a small house, in plumbing terms.
95% of teh fittings were push in type Festo fittings and we never had a problem and the water pressure was 2-3 bar on it.

Rubens

Plastic insert's for brass compression fittings???? Are u sure - sounds ropey to me!!

Rubens

rooferPete

Hi Rubens,

If I say the plastic inserts are for compression fittings without using words like maybe, possibly, I heard etc.

Then take it as Gospel and if you choose not to believe me or the other people who posted either buy the book I'm sure there are plenty, or look up Qualpex through a Google search.

We have used so many I couldn't begin to count, but if you don't have faith in the system (any system) then do like most people who have doubts, just don't use it.

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rooferPete

Hi Flocker,

Your words of caution are well earned from the the abuse I have seen the Qualpex system put to.

Attic tank : Pipes not clipped the Qualpex turned the ball valve and flooded the house.

Attic Tank : The Qualpex expansion pipe not clipped properly and the house was flooded when the immersion stat gave out.

Hot Press : pipes all over the place and couldn't take the weight imposed, result flooded house.

All were Qualpex but all were badly fitted and not DIY either.

Skills and knowledge are needed possibly more when a user friendly product like Qualpex is used, it can appear to be so easy, but the copper pipes need the skill and attention to detail that can be the difference in any job with any material being good or bad.

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tapest

rooferPete wrote:

Hi Flocker,

Your words of caution are well earned from the the abuse I have seen the Qualpex system put to.

Attic tank : Pipes not clipped the Qualpex turned the ball valve and flooded the house.

Attic Tank : The Qualpex expansion pipe not clipped properly and the house was flooded when the immersion stat gave out.

Hot Press : pipes all over the place and couldn't take the weight imposed, result flooded house.

All were Qualpex but all were badly fitted and not DIY either.

Skills and knowledge are needed possibly more when a user friendly product like Qualpex is used, it can appear to be so easy, but the copper pipes need the skill and attention to detail that can be the difference in any job with any material being good or bad.

.

Hi Rooferpete

Now I'm not doubting you ....so don't get the hump. Looking for info .

I've used the metal inserts (I thought they were copper not brass) with qualpex and compression fittings and found them great. I've no confidence in their push fittings ( 1/16 of pipe held with tear ring and O seal).I'd always be worried.....I know they were designed for the job...but....
I'm rambling Here's the question ....Is there any possibility of the plastic inserts splitting even when put under unnecessary excessive pressure?
Regards
t

rooferPete

Hi tapest,

I was a bit worried the first time I was given the plastic inserts, in fact I called two plumbers because one still had a stock of the old inserts and hadn't seen the new ones yet.

The answer I was given is the plastic is supposed to be better, it didn't make much sense to me because I was looking at the obvious difference in strength.

Appears the purpose of the insert is to allow even compression on the pipe, which did make sense.

The new plastic insert came out when the reinforcement was made better in the pipe, I can only presume the the upgrade of the pipe allowed the plastic insert to used.

I can't think of a situation where the insert would split ? the compression fitting can only be tightened as far as the thread will allow, that would mean a lot of swinging out of the fitting.

If the pipe was put under very high pressure the ring would have to tear the pipe as it worked it's way free.

I have used compression fittings on copper for an air line that was under high pressure, I think if either was to break it would be the copper because the compression ring bites into the pipe and may weaken the copper but the plastic would have to be cut.

I hope they have thought that one through or there will be a lot of buildings needing the pipes replaced.

Yes you are correct the old inserts were copper not brass, I got the habit of calling everything to do with Conex brass, sorry about that.

The O rings have been around a long time, the first time I saw them used was for an under sink water heater to say I was concerned would be an understatement the heater is still in place working with no leaks.

I sometimes wonder how sure the manufacturers are that the pipes will be clean and not have something corrosive that can attack the ring.

Similar type fittings both for plastic and copper have been in use in the UK for a long time, even on gas boilers, I remember the first time I saw the Acorn plastic fittings at the NEC Building Exhibition and with a building supplier, we both agreed they would never catch on.

Maybe we should have read the brochures and test sheets

I think a lot of the success depends on the method used to cut the pipe, a proper pipe cutter for the Qualpex gives the insert or the fitting a neat seating at the joint, pipe slice for the copper gives an even cut and allows the tectite to slide on without tearing.

Disclaimer :

All of the above are based on the writers / posters experiences and observations, sad to say he had no book to hand to refer at the time of posting

Nobody should ever have to defend asking question,

I apologise for making it appear that I am always right or Heaven Forbid that I am never wrong.

.

flocker

Slightly off topic.

I apologise for making it appear that I am always right or Heaven Forbid that I am never wrong.

From lurking and the occassional posts, your info Pete always seems to be spot on and unbiased in my opinion. You have obviously, "have been there and done that", experience and good work practice counts.

Back on topic Acorn/Hep20 have a stainless steel insert, Qualpex and John Guest have plastic inserts. The only small issue l would have in using a plastic inserts would be the smaller bore diameter as the plastic insert has a heavier wall.

I am sure the manufacturers have done all the field and in house testing before they release it on the market, particularly when they are offering 25 year+ guarantees.

The trademens l know don't use the qualpex fittings anymore they seem to have switched to use compression and use Uniwhite/Boss white.

I saw a demo of acorn being pressure tested to well over 10 bar the component that eventually failed was the fitting. The pipe didn't pull out or split it, the grab ring and O ring remaind in tact.

GreeBo

flocker wrote:

The trademens l know don't use the qualpex fittings anymore they seem to have switched to use compression and use Uniwhite/Boss white.

Why anyone would use Boss White versus acorn/qualpex I dont know
Unless of course they are charging by the hour..... :eek:

rooferPete

Hi GreeBo,

I can understand your surprise at copper being preferred over over Qualpex and other systems, but there is a lot to be said for copper.

You can fit valves or even take tees off the pipes without twisting the plastic pipes around, the copper is self supporting to a point and the fittings are cheaper.

Also using a bender the use of elbows or hoping to keep pipes tight when going around corners without kinking them is eliminated.

Opening or closing gate valves is easier and doesn't put strain on the joints, also (to me) copper can look neater and doesn't need as many clips.

Some of the old systems still have there place in the market

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