Which 25mm MDPE fittings?

[-rick-]

My flat is fed from a 32mm OD (25mm ID???) MDPE pipe. Today the water maintenance company were here to disinfect the tank on the roof and as part of that isolated the supply. When the supply came back on the right angle MDPE fitting in my ceiling started letting a lot of water out of it.

 

Seems like the fitting loses its seal when the pressure is off and then is at risk of blowing off the pipe when the pressure comes back. Managed to isolate at the meter and with extra hands reintroduced pressure while holding the fitting in place and now pressure is back on with no leaks.

 

However, my confidence in these fittings is now shot and I want to replace them. I assume I need to get compression type fittings.

 

Should I favour any specific brand? Any gotchas I should look out for?

 

 

[Nickfromwales]

There’s no way that should have pulled / blown off, unless it wasn’t seated fully into the fitting (Plasson?) properly.

 

Don’t choose compression onto MDPE as that’s garbage compared to a proper MDPE fitting + insert.

 

If you’re not sure, replace like for like, and mark on the blue pipe the depth of the fitting to the internal stop point (like a shelf that the pipe insert butts up against and then can’t go in any further) so you know the pipe is fully ‘home’ in the fitting.

 

I’d say it was poorly installed or being not fully home that caused this. 

[ProDave]

Check it has the proper insert into the end of the pipe.  Often missed out.

 

 

[-rick-]

51 minutes ago, Nickfromwales said:

There’s no way that should have pulled / blown off, unless it wasn’t seated fully into the fitting (Plasson?) properly.

 

Certainly once the pressure was off and I felt the pipe it was possible to push the fittings on by another inch with zero resistance. Pipe was completely free to move. When the pressure was turned back it pushed the fitting back out with some force as I was trying to hold it tight. Shouldn't the joint seem stiff/tight even with no pressure?

 

Just had a look on the Plasson site, nothing that matches these fittings on there (at first glance).

 

51 minutes ago, Nickfromwales said:

Don’t choose compression onto MDPE as that’s garbage compared to a proper MDPE fitting + insert.

 

I meant compression MDPE like this, in case that wasn't clear: 

https://www.pipestock.com/mdpe/mdpe-pipe-fittings/mdpe-elbow-90

[-rick-]

Looks like the existing are Talbot:

 

https://www.plumbingforless.co.uk/plumbing/atplas-talbot-mdpe-fittings/talbot-elbows/talbot-pushfit-90-degree-elbow-32mm-e2784

[-rick-]

FWIW these fittings are approx 20 years old. Google suggests a known failure of them is o-rings failing due to age (15-20 years).

[Nickfromwales]

5 minutes ago, -rick- said:

 

Certainly once the pressure was off and I felt the pipe it was possible to push the fittings on by another inch with zero resistance. Pipe was completely free to move. When the pressure was turned back it pushed the fitting back out with some force as I was trying to hold it tight. Shouldn't the joint seem stiff/tight even with no pressure?

 

Just had a look on the Plasson site, nothing that matches these fittings on there (at first glance).

 

 

I meant compression MDPE like this, in case that wasn't clear: 

https://www.pipestock.com/mdpe/mdpe-pipe-fittings/mdpe-elbow-90

Ah! Gotcha. Yes, that type of fitting is also robust.

 

Being able to push the pipe an inch means it wasn’t past the o ring, so you were living on luck there!!

 

 

yup. Just found the bugger lol. 

[Nickfromwales]

Just now, -rick- said:

FWIW these fittings are approx 20 years old. Google suggests a known failure of them is o-rings failing due to age (15-20 years).

I know the feeling. Some of my seals are less robust these days   

 

Sounds like an issue to put back on the leaseholder? Or have you signed your life away? 

[-rick-]

Just now, Nickfromwales said:

I know the feeling. Some of my seals are less robust these days   

 

😆

 

Just now, Nickfromwales said:

Sounds like an issue to put back on the leaseholder? Or have you signed your life away? 

 

I am the leaseholder. Would dearly like not to be but stuck here until the cladding issue on this building is fixed (even then flats in London are not in high demand right now so I'm likely stuck here for a while).

 

So what should I do? This is the second time this fitting has leaked after tank maintenance. Trust it, despite it being very loose (even after pushing back on as best I could with the access)? Replace with same fitting? Or something else?

[Nickfromwales]

31 minutes ago, -rick- said:

 

😆

 

 

I am the leaseholder. Would dearly like not to be but stuck here until the cladding issue on this building is fixed (even then flats in London are not in high demand right now so I'm likely stuck here for a while).

 

So what should I do? This is the second time this fitting has leaked after tank maintenance. Trust it, despite it being very loose (even after pushing back on as best I could with the access)? Replace with same fitting? Or something else?

Replace with new, I’d go Plasson. 

Edited 22 hours ago by Nickfromwales
My phone is dyslexic

[ProDave]

I would replace with this. https://www.screwfix.com/p/floplast-492015-mdpe-elbow-25mm-x-25mm/14096

 

Part of the locking mechanism when you tighten the compression bit is they physically dig into the pipe so there is no way they will pull out without dismantling the fitting.  You First push the pipe into the fitting and you can check it has pushed properly into the O ring seal only then do you tighten the compression bit which ensures it is not coming out, pressure or no pressure.

 

All my mdpe pipe is connected with that type of fitting.

[Alan Ambrose]

>>> Should I favour any specific brand?

 

+1 Plasson

[-rick-]

Right so Plasson it is.

 

Plasson Compression or Push fit?

 

For the elbow:

 

https://www.pipestock.com/plasson/pushfit-fittings/plpf-elbow-90 (350107 - 32mm push-fit)

https://www.pipestock.com/plasson/compression-fittings/plmf-elbow-90 (352354 - 32mm compression)

 

For the copper connection:

 

https://www.pipestock.com/plasson/pushfit-fittings/coupling-pe-x-copper (350068 - 32mm to 28mm push fit)

https://www.pipestock.com/plasson/compression-fittings/adaptor-male-bsp (352288 - 32mm to 1 1/4"/28mm compression)

 

Plus 32mm pipe liners x 3:

 

https://www.pipestock.com/pipe-liners

 

The order process recommended a Boa Strap Wrench as well for the compression fittings.

 

This will be my first time doing something like this so a few more questions:

 

1. Will I need to/should I be prepared to trim the ends off these MDPE pipes to get a good end?

2. If so, I assume I need pipe cutters. Deburring tool? Probably try and find a short length of pipe as well as a straight connector as there isn't much slack anywhere.

3. If using compression to the copper side, do I need PTFE/thread sealant? New olive?

4. If using push-fit, should I plan to cut the pipe and make a new fresh end? So pipe cutters and wire wool?

5. No pipe liner required for the copper end if using push-fit, right?

5. Anything else I'm not thinking of?

 

 

[Nickfromwales]

@-rick-

Firstly, a warning! If this is a block of flats and you’re not on the ground floor, this could be disastrous if you feck it up. Just saying that so I can sleep later  
 

Is it easier for you to cut out the elbow and convert to copper where it’s accessible there, then just run 28mm copper to where it currently converts?

 

No need for spanner’s and grips, nuts and olives, PTFE etc or other faff.
 

You only need Hep2o 28mm fittings then, including being able to cut off the nut and olive at the existing copper tail and push a straight Hep2o coupler on to that.

 

Much more DIY friendly route, and less tools / prep etc. Just needs a 28mm pipe slice. A Jnr or Snr hacksaw will cut the MDPE if you can borrow one. Cut it square, and use a £2 sanding block from one of the sheds to apply a very slight chamfer to the pipe before pushing in the insert.

 

The conversion from MDPE to copper can be Plasson push fit, just needs an insert to go into the MDPE pipe (no inserts required in copper) and that’ll be right for life.

 

Give the rubber O-rings the slightest smear of Vaseline, just a whiff, to ease pushing the MDPE into the fitting. Remember to measure the depth of the stop inside the fitting, use a pencil / other depth gauge, and mark this onto the MDPE before pushing it in, so you know it’s fully home. 
 

All copper cuts made with a rotary pipe slice will automatically be ‘chamfered’ and do not need to be ‘de-burred’.

 

How’s that sound?

 

Re my ‘warning’, I’d do the repair DIY, and recommend that you switch the mains off for the next few days when you head out to work. Then have it on and be using it whilst you’re there, until you are fully confident that the repair is kosher.

[-rick-]

3 hours ago, Nickfromwales said:

Firstly, a warning! If this is a block of flats and you’re not on the ground floor, this could be disastrous if you feck it up. Just saying that so I can sleep later  

 

Appreciate that, it's why I'm not rushing to do it and asking lots of questions, it's not leaking right now so I can afford to take my time. I think it's approachable in my situation because:

1. There is a ball valve isolator about 10m away from my front door that I know works because I used it yesterday when the fitting was leaking. I can use that for isolation and it's close enough that I can reach it in a hurry if something goes wrong.

2. I am at home most of the time and wouldn't be leaving any new change unattended.

 

Feel free to tell me I'm crazy.

 

3 hours ago, Nickfromwales said:

Is it easier for you to cut out the elbow and convert to copper where it’s accessible there, then just run 28mm copper to where it currently converts?

 

I'm not sure it is. I can't see a plasson option for a 90 elbow MDPE->copper so I'd have to take the copper above the plasterboard, 90 there and then convert to MDPE with a straight coupling, while stiff the MDPE pipe still has a bit of flex in it. I'll attach a video showing the space available.

 

 

 

If I have to cut the MDPE pipe back anyway from the elbow and attach a straight coupler there then it's the same number of fittings either way.

 

3 hours ago, Nickfromwales said:

Much more DIY friendly route, and less tools / prep etc. Just needs a 28mm pipe slice. A Jnr or Snr hacksaw will cut the MDPE if you can borrow one. Cut it square, and use a £2 sanding block from one of the sheds to apply a very slight chamfer to the pipe before pushing in the insert.

 

The prices on the pipestock website for the right tools are low enough that the right tools isn't a barrier. Given the access available I think I'd prefer to use a ratcheting plastic pipe cutter than a hacksaw (feel I'd make a right mess of the pipe with a hacksaw).

 

3 hours ago, Nickfromwales said:

The conversion from MDPE to copper can be Plasson push fit, just needs an insert to go into the MDPE pipe (no inserts required in copper) and that’ll be right for life.

 

Give the rubber O-rings the slightest smear of Vaseline, just a whiff, to ease pushing the MDPE into the fitting. Remember to measure the depth of the stop inside the fitting, use a pencil / other depth gauge, and mark this onto the MDPE before pushing it in, so you know it’s fully home. 
 

All copper cuts made with a rotary pipe slice will automatically be ‘chamfered’ and do not need to be ‘de-burred’.

 

How’s that sound?

 

That all sounds fine.

 

3 hours ago, Nickfromwales said:

Re my ‘warning’, I’d do the repair DIY, and recommend that you switch the mains off for the next few days when you head out to work. Then have it on and be using it whilst you’re there, until you are fully confident that the repair is kosher.

 

I'm home most of the time anyway so this isn't a problem.

Edited 3 hours ago by -rick-
Added video

[Nickfromwales]

You’d convert MDPE > copper in a straight fitting, then go into a hep2o 90° bend. Not convert with a bend. I’ll watch the vid shortly. 👍

[-rick-]

Video showing a bit more of what’s in the ceiling

 

.

 

 

Edited 3 hours ago by -rick-