How to undo connectors?

Ambergreen45 · 19 Nov 2018

Hello,

I want to fit a mixer tap on the kitchen sink but the metal thread which goes through the sink tap holes are too long, therefore I will need to cut some pipe work to be able to fit it.

1. By hand, how do I undo the straight white plastic connector's top, clockwise or anti-clockwise and where do I grip it with the other hand so as not to damage the rest of the pipework?

2. With a spanner, do I undo the washing machine metal straight connector's top, clockwise or anti-clockwise and where do I grip it with the other hand or other spanner so as not to damage the rest of the pipework?

3. I will need to cut about an inch at the bottom on both bent copper pipes. When I insert a new olive, can I cover it with a bit of PTFE tape to make it more water tight before securing them back to both connectors?

4. In case I mess something up and need to cut some pipe already in place with a hacksaw, should I be concerned with the possible metal residues falling into the pipe, as there would possibly be no way to flush the system before installing the mixer tap?

5. Finally, as per the mixer tap instructions, it says I will need a Non Return valve, but will I need that, since the mains water supply pipe comes directly from the ground underneath and the water pressure is very high?

Many thanks for your help and advice.

SammyInnit · 19 Nov 2018

Ambergreen45 said:
When I insert a new olive, can I cover it with a bit of PTFE tape to make it more water tight before securing them back to both connectors?

No point, that's what the olive is for.

Ambergreen45 said:
In case I mess something up and need to cut some pipe already in place with a hacksaw, should I be concerned with the possible metal residues falling into the pipe, as there would possibly be no way to flush the system before installing the mixer tap?

Pipe slices are dirt cheap and would be much easier to use in a tight space. https://www.screwfix.com/p/3-28mm-manual-multi-material-pipe-cutter/49428

I would recommend you deburr them too using a reamer but they're quite a bit more expensive so do your best with some emery paper.

Ambergreen45 said:
Finally, as per the mixer tap instructions, it says I will need a Non Return valve, but will I need that, since the mains water supply pipe comes directly from the ground underneath and the water pressure is very high?

Yes.

Burnerman · 19 Nov 2018

All of the connections undo anticlockwise.....hand force is usually enough to undo plastic fittings but you could probably use Mole grips or slip joint pliers to hold the valve body as you undo the brass nut.
A pipe slice is a much better way to cut copper, but if you are concerned about debris in the pipe, turn any taps full on as you open the main stopcock to flush things out.
You can ptfe over an olive if you like, but a sealing compound could work just as well.
John

Ambergreen45 · 19 Nov 2018

SammyInnit said:
Yes.

About fitting a non return valve to prevent backflow, all I can see at the moment is an isolating valve fitted just after the stopcock and then the pipes separate, one to the combi boiler to return to the taps for hot water and the other for cold water. I always had 2 kitchen taps before replacing them to a mixer tap. Do I have to fit a non return valve only because I will be fitting a mixer tap? Sorry, I don't know much about it. Would it be quite tricky to install?

terryplumb · 19 Nov 2018

A non return valve is to prevent hot water going into the cold ,drinking water ,supply. On two seperate taps they cant mix ,but they can on a mixer. Easy to fit ,compression fitting on each end .

SammyInnit · 19 Nov 2018

Ambergreen45 said:
About fitting a non return valve to prevent backflow, all I can see at the moment is an isolating valve fitted just after the stopcock and then the pipes separate, one to the combi boiler to return to the taps for hot water and the other for cold water. I always had 2 kitchen taps before replacing them to a mixer tap. Do I have to fit a non return valve only because I will be fitting a mixer tap? Sorry, I don't know much about it. Would it be quite tricky to install?

I believe your can get compression check/non return valves so not too difficult.

In its most basic description, it's to stop your heated water and water supply going backwards. Standards say they have to be protected.

Ambergreen45 · 19 Nov 2018

SammyInnit said:
I believe your can get compression check/non return valves so not too difficult.

In its most basic description, it's to stop your heated water and water supply going backwards. Standards say they have to be protected.

So, on my picture, I suppose I can replace the first bent copper pipe with 2 small straight ones joined with an elbow and then fit the non return valve horizontally, just before the other elbow connected to the tap?

endecotp · 19 Nov 2018

Ambergreen45 said:
So, on my picture, I suppose I can replace the first bent copper pipe with 2 small straight ones joined with an elbow and then fit the non return valve horizontally, just before the other elbow connected to the tap?

Would it be easier for you to keep the existing bent copper and shorten the vertical plastic pipe, and fit the non-return valve there?

terryplumb · 19 Nov 2018

endecotp said:
Would it be easier for you to keep the existing bent copper and shorten the vertical plastic pipe, and fit the non-return valve there?

Thats the hot supply pipe is it not ? Wouldnt do any harm ,but would not prevent hot from entering the cold supply , a check / non return valve must be on the cold supply. So only allows cold into mixer and prevents backflow .

endecotp · 19 Nov 2018

terryplumb said:
Thats the hot supply pipe is it not ?

D’oh, sorry, of course that’s the wrong pipe. Please ignore me!

terryplumb · 19 Nov 2018

endecotp said:
D’oh, sorry, of course that’s the wrong pipe. Please ignore me!

.......who said that .......

Ambergreen45 · 19 Nov 2018

terryplumb said:
Thats the hot supply pipe is it not ? Wouldnt do any harm ,but would not prevent hot from entering the cold supply , a check / non return valve must be on the cold supply. So only allows cold into mixer and prevents backflow .

Good thing I've asked. Yes, the first pipe starting with plastic is the hot water supply. I've seen a couple of videos and they fitted the check/non return valve (with an arrow on the valve) on the hot water pipe, but for basins. So for the kitchen I will fit it on cold supply, but by doing that, would cold water from the mains enter the hot water supply?

terryplumb · 19 Nov 2018

You fit two ,one on cold supply and one on hot. There doesnt appear to be much space / access ,to work in ( unless your pics are deceiving ) .there appears to be blue handle isolation valves ,lower than the one that has the hose fitted to ( washing machine is it ), and they are capped off .so assume not in use ? If so ,you could swap the hose to a lower one ,if it wiil reach ,and free up space above for the check valve.

Ambergreen45 · 20 Nov 2018

terryplumb said:
You fit two ,one on cold supply and one on hot. There doesnt appear to be much space / access ,to work in ( unless your pics are deceiving ) .there appears to be blue handle isolation valves ,lower than the one that has the hose fitted to ( washing machine is it ), and they are capped off .so assume not in use ? If so ,you could swap the hose to a lower one ,if it wiil reach ,and free up space above for the check valve.

I have included a second picture showing the rest of the pipe that connects to the taps. I just wonder, would it be too tight if I were to have both pipes at an 90 degree angle each (with an elbow) rather than curved, with the check valves fitted horizontally, ie between elbows?

If not, as the pipes are so close to the wall, I may have to cut them using a hacksaw. I've just read the fitting instructions again which mention to flush the system of cutting debris before fitting the tap. I would normally let the debris flow through the tap, but there is an aerator stuck to the spout. I can't really flush it before fitting, can I?

Would a couple of those singles ones do? https://www.toolstation.com/shop/p77952

SammyInnit · 20 Nov 2018

You'll get a small slice in there. Don't forget copper is quite soft and you'll get enough movement as long as you're careful to get a small slice in.

The valve you've linked to looks fine.

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How to undo connectors?

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