Leaking toilet cistern pipe to valve

[scousekevin]

Hello I wanted to fit an isolating valve to the supply to the toilet cistern so as to reduce the water pressure. The cistern has a shutoff valve with a small rubber diaphragm type shut off and if pressure is to high it keeps filling and overflows into toilet.

I have posted a photo, new copper pipe cut with pipe cutter and some ptf tape on thread. I put a bit extra on pipe that comes out of cistern as its plastic and it was leaking without the extra tape. It is still leaking and I am hoping some one can tell me what would be best type of fitting to use to get a proper connection onto the cistern pipe.

I know of flexi connectors but don’t know what size type would be best. Any help much appreciated. Thank You

 

[centralheatking]

View attachment 41246
Hello I wanted to fit an isolating valve to the supply to the toilet cistern so as to reduce the water pressure. The cistern has a shutoff valve with a small rubber diaphragm type shut off and if pressure is to high it keeps filling and overflows into toilet.

I have posted a photo, new copper pipe cut with pipe cutter and some ptf tape on thread. I put a bit extra on pipe that comes out of cistern as its plastic and it was leaking without the extra tape. It is still leaking and I am hoping some one can tell me what would be best type of fitting to use to get a proper connection onto the cistern pipe.

I know of flexi connectors but don’t know what size type would be best. Any help much appreciated. Thank You
View attachment 41247

Before you carry on scouse I would take a long hard look at the connections to determine
just where the leak is dripping from...from your pics I can see up to 3+ likely places..do not
always just go for the obvious with water ..its lazy stuff and can be a puzzle.
Get some bog paper and work downwards to check just where the leak.s might be
coming from....also do you know where and does your mains supply switch off, if not
its best to find it before you go too much further...centralheatking

 

[Brambles]

If I were in your shoes, I would take on board what CHK has said above. Then replace the cistern inlet valve with a quality one that has a brass stem and a high pressure insert. Keep the isolation valve, but have it fully open - if you use the isolation valve to try to reduce the flow ( it wont change the pressure) it just creates noise.

Connecting (without leaks) to a threaded plastic stems with a brass connector is more of an art than a science. If you don’t get it right first time give up and buy a valve with a brass stem.

Joking apart, don’t underestimate the damage that these connections can cause if and when then fail. They are very often the weakest point in the cold water supply to a domestic dwelling

 

[ShaunCorbs]

inlet valve looks cross threaded

 

[king of pipes]

Brambles advice is how I would go replace the inlet valve for a high pressure brass stemmed one . Regards kop

 

[scousekevin]

Hello Thank you all for the advice I know it is the inlet valve connection that’s leaking (more of a weep than a leak)I have used the tissue test before.
I have purchased a Flomasta Flush valve kit might as well replace the innards in one go. It has a brass shank so eliminates the metal to plastic problem.
The old cistern retaining bolts are badly rusted and once the cistern is off I can give the whole thing a good clean.
I didn’t realise that you could buy these with a metal shank, I thought all modern ones were plastic lol
Thanks Again

 

[steadyon]

1. You don't have to remove the cistern to change the inlet valve.
2. If you do remove the cistern, you will also need a new "doughnut" washer. They aren't all the same.
3. If your leak is coming from the connection between the new copper pipe and the plastic threaded shank of the inlet valve, the most likely culprit is failure to put a new fibre washer into the connection.
4. Putting PTFE tape on threads, other than on tapered threads, is a compete waste of time with respect to creating a seal. The seal is made by the olive or fibre washer (depending on the type of connection). It is not made on the threads. I know some people think it reduces friction, but so would a tiny drop of oil or thin smear of silicone grease.

 

[scousekevin]

Thank you for the advice this morning I fitted the Flomasta Flush valve kit, the existing cistern bolts were rusted up an caused a slight delay but the metal to metal connection ont he water feed has done the trick.
Thank You Everyone

 

[ShaunCorbs]

You did replace the fibre/ rubber washer on the connection to the valve didn’t you ?

 

[scousekevin]

I wanted to fit an isolating valve to the supply to the toilet cistern so as to reduce the water pressure. The cistern had a shutoff valve with a small rubber diaphragm type shut off and if pressure was to high it kept filling and overflowed into toilet.
Having replaced the old mechanisms in the cistern I no longer needed the valve and I can now increase the water pressure without it affecting the cistern.
Thanks for the reminder though