installing a new cistern

[pikavaai]

hi all,

i couldnt find exactly my issue, as i dont know what this design called.

im fitting a new flushing and filling mechanism. the filler element is the problem, as the pipe that connects to the cistern tap (the quick shut off one) is flattened?!

so its a half the thread, and the sides of the pipe are flat, hence water forces itself through the tiny spaces after everything is tightly screwed up. ive put in hard washers, soft ones, ptfe tape, nothing seals this.

im gonna attach a drawing quick. its only about the flattened sides of the pipe, no stress about the cistern or tap parts, they work fine.

is this a known design, or manufacturing issue? the unit cost a pretty penny. they say do not use putty. i would imagine the oil will disintegrate the plastic over some time.

 

[ShaunCorbs]

Any chance of a picture of the item ?

 

[pikavaai]

here is the unit off the hardware store website. my one is outside at the moment. its 20h00 here.

 

[ShaunCorbs]

Would say there supposed to be there have you tried an oring and just 1/4 turn when tight ?

 

[Timmy D]

Would say there supposed to be there have you tried an oring and just 1/4 turn when tight ?

I agree that the flattened side are by design to allow a spanner when tightening.

What are you trying to connect to the bottom? Can we get a pic? Needs to be a tap connector/braided hose. The seal is made at the bottom of the fill valve (horizontally across the flat face of the pipe/valve inlet), not at the threads. This seal will be made with a washer.

 

[pikavaai]

Would say there supposed to be there have you tried an oring and just 1/4 turn when tight ?

thanks, yes i have tried washers, hard ones too, quite tightly turned..water keeps coming... pictures attached, you can see the flattened side...

the first picture is the completed fitment, the water runs through where you see the ptfe tape. the pipe is screwed up right into the small shut off ball-valve, inside is a washer too...water still leaking once the valve is opened.

 

[pikavaai]

I agree that the flattened side are by design to allow a spanner when tightening.

What are you trying to connect to the bottom? Can we get a pic? Needs to be a tap connector/braided hose. The seal is made at the bottom of the fill valve (horizontally across the flat face of the pipe/valve inlet), not at the threads. This seal will be made with a washer.

thanks, yes you may have a point, its probably for a spanner, perhaps to counter turnforce. agree, the seal is made at the flat face, however can you believe i put a big enough washer there, but as you tighten the ball valve, it compresses the washer inside into the pipe! its the strangest thing. perhaps a fibre washer must be used..i dunno

 

[Basher]

You need a 'tap-connector' to seal to that plastic stem
The metal valve/tap you are using almost certainly doesn't have the required seating for a fibre washer as shown below
In the UK we could use this:

https://www.NoLinkingToThis/p/strai...V6oBQBh23lgCtEAQYASABEgKKyPD_BwE&gclsrc=aw.ds

Note how the fibre washer is held in place by the lip inside it. This makes a flat seal against the end of your plastic thread -the flat sides on the thread won't matter, as per previous postings tried to explain. All the 'seal' is provided by the washer being compressed by the two annular surfaces (which need to be flat and undamaged) - the thread shouldn't play a part as a seal, and you shouldn't need ptfe tape on it.
Can you find an equivalent locally? You will probably need to modify the pipework.

 

[Deleted member 120897]

Also be mindful, you may have cross threaded the connection and chewed the inlet valve stem being plastic.

 

[pikavaai]

You need a 'tap-connector' to seal to that plastic stem
The metal valve/tap you are using almost certainly doesn't have the required seating for a fibre washer as shown below
In the UK we could use this:

https://www.NoLinkingToThis/p/strai...V6oBQBh23lgCtEAQYASABEgKKyPD_BwE&gclsrc=aw.ds

Note how the fibre washer is held in place by the lip inside it. This makes a flat seal against the end of your plastic thread -the flat sides on the thread won't matter, as per previous postings tried to explain. All the 'seal' is provided by the washer being compressed by the two annular surfaces (which need to be flat and undamaged) - the thread shouldn't play a part as a seal, and you shouldn't need ptfe tape on it.
Can you find an equivalent locally? You will probably need to modify the pipework.

thank you, ill have to try what else fits, as the brass pipe is cemented into the wall, and the cistern has of course remain in exactly the same space, so the pipework changing will be tricky. i will have to consider a braided hose and ball valve setup.

 

[Basher]

If you have scope to shorten or move the pipe slightly, and you can find an equivalent of the one below, then maybe this 'tap-adapter'/ service valve version (which I believe has a proper seat for a washer) could be fitted in.

Pegler Yorkshire Ballofix Service Valve Straight Swivel Pattern Plastic Lever - 15mm x 1/2 inch | Plumbing Superstore®

This 15mm x ½ inch Ballofix service valve from Pegler Yorkshire is straight with a swivel pattern. This Ballofix service valve includes compression x BSP u...

www.jtmplumbing.co.uk

 

[pikavaai]

If you have scope to shorten or move the pipe slightly, and you can find an equivalent of the one below, then maybe this 'tap-adapter'/ service valve version (which I believe has a proper seat for a washer) could be fitted in.

Pegler Yorkshire Ballofix Service Valve Straight Swivel Pattern Plastic Lever - 15mm x 1/2 inch | Plumbing Superstore®

This 15mm x ½ inch Ballofix service valve from Pegler Yorkshire is straight with a swivel pattern. This Ballofix service valve includes compression x BSP u...

www.jtmplumbing.co.uk

thanks for your help, yes, ill have to consider using other parts. i tightened everything up again, connected a hose pipe and it was fine. then i installed it all, the ball valve super tight on the threaded pipe, it still drips about 1 drop per hour. i will make a turn at the hardware shop again to check my options. thank you to all.

 

[Ric2013]

Have you tried twisting a piece of PTFE tape into a thread and wrapping it around where a a tap connector washer would usually go? I once had to do this as a fibre washer leaked - but this worked.

 

[pikavaai]

Have you tried twisting a piece of PTFE tape into a thread and wrapping it around where a a tap connector washer would usually go? I once had to do this as a fibre washer leaked - but this worked.

Thanks, I have not tried that... i will surely give it a try when i disassemble the whole lot again. so you mean, twisting it between your fingers, like a thin yarn, then lace it around the thread..clockwise of course.

 

[Ric2013]

Thanks, I have not tried that... i will surely give it a try when i disassemble the whole lot again. so you mean, twisting it between your fingers, like a thin yarn, then lace it around the thread..clockwise of course.

No. Twist it between your fingers to make a thread, but don't try to create a thread seal.

I've re-viewed your pics and think I see your problem though. It looks like that isolation valve has female threads and whoever has installed has tried to seal onto the thread of the plastic valve tail. This won't work. You need a tap connector fitting. Something along these lines

https://www.NoLinkingToThis/p/pegler-straight-service-valve-15mm-x/19933

that is designed to seal onto the end of the plastic. I was suggesting you might need to use PTFE 'string' instead of the red fibre washer that is normally supplied, but use the red washer if it works.