Question about pushfits

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Having grown up with compression and solder fittings for copper pipe I guess I've missed the introduction of pushfits, but as I'm still young enough to learn new tricks......
I understand the basic principles of pushfit connections. But the thing that has put me off a bit has been that under pressure I felt they might give way. Obviously that's not the case otherwise other people wouldn't be using them.
So how do you release a pushfit joint after you've made it? If the thing has the ability to increase its grip when the pipe tries to come out (as it must do) then I'm curious as to how you "persuade" the joint that you want it to break.
And (assuming you can release it) can these joints be re-made afterwards, or do you replace the fitting?
Finally for the pushfit beginners course, are there different pushfits for copper and plastic pipes, or are the pushfits common?
Sorry if these are real dumb questions from plumbing 101, but like all these things you have to start somewhere and because I've always had a viable alternative I've been reticent to give pushfits a try.
PoP
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AFAIK pushfits have a separate 'key' which fits around the pipe and gets pushed into the collar of the fitting, this releases the catch and you can remove the fitting. AFAIK you can then remake the joint.
AFAIK there's copper pushfits (look in Screwfix I think) for copper pipes, though these are more expensive. I'm not sure if these are a cosmetic choice or required.
AFAIK I've never handled pushfits or used them... ;) But I've looked at them in catalogues!
D
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David Hearn wrote:

Some people have this 'gut feeling' they're bad, but I've never heard of any problems if they're assembled properly.

Speedfit have a little collar you depress to release the fitting. It can be a bit of a bugger to do!

Certainly can with Speedfit. I think there's a permanent flavour of Hep2o if you want it.

Just cosmetic. You can use plastic or copper pushfits on plastic or copper pipe. If you use pushfits on plastic pipe you must use pipe stiffening inserts. With these you can use regular compression joints on plastic pipe too.

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They are about the same price now as plastic fittings. Coppe pipe is far cheaper than plastic
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wrote:

The pressure tends to force the pipe more against the serrated gripping ring. If you think about the barb of a bee's sting or the back pointing teeth of a constricting snake, the idea becomes clear.
There are also pipe inserts, which stiffen and locate the pipe better in the fitting.
I quite like JG Speedfit because their insert also has an additional O-ring and there is a twisting lock ring on the top as well.
Try getting a length of pipe and attaching a fitting. Then try to pull it off.....
I also found that their technical department was very helpful in providing advice on use of their products.

It varies between brands. There is generally a plastic ring at the mouth of the fitting, which when pushed in releases the teeth of the gripper. On some this can be done by hand, on others a special release tool is needed.

I've done this, but it's probably not a good idea. I wouldn't use the fitting more than once more, and on a high pressure system would replace.

There are pushfits for copper, but the ones for plastic will take copper tube to allow connection to a copper system.

In some cases it's a real time saver. The flexibility is useful when pipes need to be routed awkwardly - for example through holes in successive joists. However, the pipe does need more support than copper as heat tends to let it sag.
It's essential to have one of the proper slicing pipe cutters, because having a good cut end that is square and free of swarf is important. You can also cut on the pipe markers and then know that the pipe has been pushed fully home into the fitting.

.andy
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This insert is also plastic. Other makes have steel inserts which stiffen up the fitting more. Marley Equator has steel inserts and steel encapsulated fittings too. Polyplumb and Hep2O are very bulky fittings and look awful.

The makers always say replace the fitting, as the O ring can be cut on pipe serrations on the pipe made by the grab rings in the fittings.

But may warp with high temperatures under stress which the copper or brass fittings will not.

But make entail far more time in the future.

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Well so far they don't give way too much. Come back in 25 years time. I was talking to the maintenance plumbers of a large developers, who install Speedfit for the first fix and copper where the customer sees pipe. None of them are complimentary of Plastic pipes. As the Speedfit is under floors they are constantly taking up floors, or cutting in access hatches to get at the pipes that have failed. they said with soldered copper they only had a faction of the problems. generally, if soldered copper held for the test period before handover it was fine.
The problems with plastic fittings is not stressing the joint, so not putting them too near bends and having them well clipped reduces future failures.

A realse tool, which is cheap. Each make is different.

All makers of plastic fittings say their fittings can be used on other makes. But most say don't as tolerances may vary between makes. All say their fitting can be used on copper pipe.

If you are comfortable with copper soldered joints and compression joints stick with them. See my other post re: plastic. BTW, I rate Marley Equator the best plastic pipe system.
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I'd say it's the crappy "tradesmen" that don't like plastic as they have to pay more than a few pence for the fittings and they can't just jam pipe anywhere or put in bends when they can't be arsed to move a section that doesn't line up with the joists etc. They have to spend time fastening runs up when they could be down the pub hanging their arses out after leaving a 30ft run of copper hanging in mid air coz it'll do or a joint that's nearly watertight but it'll seal up after a bit .... ;-)
Why do I say this? Coz I've been checking out any pipework I can anywhere I can after learning how to solder copper - if I'm shit then there's people doing it for a living who are a lot shittier than I am from the quality or lack of it in their work :-)
Mark S.
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wrote:

I do hope that wasn't intended as a slur on my character!
The reason I haven't moved to pushfits thus far is simply because I grew up with solder and compression joints, pushfit came along a lot later (when did pushfit arrive? I missed the announcement).
It seems to me that a lot of people around these parts are very happy with pushfits - and that gives me confidence to give them a try. I shall be installing a bath in a little while and I'm contemplating giving pushfits a go for the tap plumbing (generally speaking there is no room to swing a spanner nor to set the flamethrower in the gap).
But I don't think your comment is entirely valid - a crappy "tradesman" is going to be crappy with any type of fitting, and someone using pushfit doesn't necessarily make them a decent plumber.

I think you have to recognise that those tradesmen might have had their original work interfered with long after they left site. It is an unfortunate consequence of the have-a-go-heroes that operate in the DIY field.
PoP
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A neighbour had a Speedfit elbow fitting in a wall. The electrician of the conservatory company installing the conservatory, jammed plastic conduit over the plastic Speedfit. the pressure on the fitting caused it to leak and destroying a laminate floor. Firstly if it was a soldered fitting it would have been OK, Secondly, garbage tradesmen are well, just garbage tradesmen with any fittings, water or electrical.
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These are "new" un-interferred with heating system installs not years old stuff like mine was before I ripped it all out. I can solder better any day of the week than some i've seen being paid as qualified tradesmen to do it. I simply think some people are born sloppy/uncaring about the standards of work they achieve and do as little as possible to earn their money. The ones who do care are either scarce or too expensive for the places I've visited. :-)
No slurs on anyone intended just saying what I've seen now I've been paying attention to plumbing. ;-)
Mark S.
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faults that are being created by the builders. The main one being inadequate support of bends which gives rise to lateral pressure on the O ring. Three years down the road and the joint leaks. Also, how do we know if the pipe was cut using the correct tool, or with just a pair of secateurs (as I have seen 'recommended' on an under floor heating site).

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Andrew

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Hi PoP,
The Polyplumb pushfit fittings I've used have a screw-on cap that holds the O ring, spacers and metal-toothed grab ring in place. To remove the fitting from the pipe, you undo the screw-on cap. You can then cut the grab ring off with a pair of pliers - dead easy. To remake, simply replace the grab ring and all other 'innerds' and push a new pipe in.
You can use these plastic fittings on either Cu or plastic pipes. However, they're not suitable for use with chrome plated pipes - I guess because the grab-ring can't grab to the shiny chrome surface.
Hope that helps,
Matt
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Plastic is becoming the norm but like any fittings they need to be put on right, follow the instructions and they work fine. There have been very few reports of problems and most of the rubbish spouted on here from one particular source is uninformed babble.
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David

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writes

The "norm". It has been around for a long time and still only accounts for 15%, at most of the market.

I have been involved in pipes most of my working life. I advise you to Google my posts on plastic and take notice. Nothing worse than a know-it-all amateur with no experinece to back up the babble.
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Or a stick in the mud? ;-)
Mark S.
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writes

Yes, and these don't progress. Intelligent people assess matters correctly.
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writes

John, if you care to look back yourself, you'll notice I have been around since you started spouting off about plastic, remember all the belongs in the toy box stuff? You are slowly but surely changing your tune and accepting the inevitable. I believe your opinions are just that regarding plastic and you have very little plastic experience yourself to back it up, you really ought to stop inventing neighbours or "someone I was talking to the other day" to back up your theories, it really doesn't do your credibility any good. There are a number of us here who actually *have* plastic installations.
Please select from any of the following: uninformed babble calling me Maxie wears Cat boots know it all amateur colouring in DIY book
Please feel free to add to the list as necessary, your MO is pretty familiar to us all by now
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David

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writes

had an honours degree in computer science, was part of that heating?

weakening of position? Professionals are using plastic more and more, have a look in their vans, you won't see many (if any) without it now, times are a changing and you stick in the muds had better get used to it, its refusing to accept progress that's holding this country back, I expect you would vote against a land value tax and be against redistribution of wealth as well
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Maxie, you are confusing me with someone else.

Wow! a an amateur physiologist too!!!

Still only a tiny percentage of total used.

Are you referring to me or the other one in your mind?

Now a political speech.

Never in a million years. You have the wrong person. Go and find him and post to him.
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