How to tighten this fitting please?

[Dhillon]

Hi,
I had to unscrew this plastic fitting which is part of an existing water softener install. Now it leaks when tightened and I think its because I am not tightening it properly. Its a strange fitting as it has the rubber washer half way up the thread. Can someone please explain how this type of fitting should be tightened?

Cheers

 

[terryplumb]

The seal shouldn't where it is ,it should be between the female fitting and the bottom of the male thread

 

[Madrab]

Either that or that threaded male end should screw fully into that fitting and you haven't aligned the threads properly, looking at that top thread it could be cross threaded.

 

[Elkato531]

Screw it in as far as you want it and then screw the knurled ring up to compress the o ring perhaps.

 

[DIYspanner]

I'd say the o ring is too fat and not the one intended for the job. The elbow inserts into threaded neck and there's a lip on the elbow to butt up against the neck's end. The o ring should be seated between the two. Just my opinion from the diy plumbing I've done.

Here's the idea albeit not Picasso standard.

 

[Madrab]

The alternative is that the o-ring sits on the shoulder of the male spigot and tightening the male fitting all the way in traps the oring between the base of the spigot and the shoulder of the fitting. Which is why the oring is where it is at the moment, unscrewing it has allowed the oring to rise up the thread a little as it was stuck against the shoulder of the female section. Or as Elkato suggests, which would allow the direction of the elbow to be universal to suit any location.

OP how did it come apart, was the o-ring always on the threaded section as it is in the pic or did you fit it onto it? Does the bottom knurled ring screw up the male threaded section?

 

[DIYspanner]

Any chance of a photo of the elbow removed and a view of the inside of screw on end with the locking collar slid along from the end?

 

[Dhillon]

Hi, Here are some more pics. So far I have put the rubber seal in the middle (where there seems to be a slot for it and that's where the seal was when I first unscrewed it) and screwed it into the female so it is tight, then screwed up the knurled ring. Will keep monitoring for leaks.

 

[DIYspanner]

From what I can fathom, the elbow, with the o ring fitted, screws up into the spout until the o ring is seated the groove then the knurled collar screws up to lock the joint.

Is the o ring in good condition?
Are the o ring seats clean?

 

[Madrab]

Yup, you can see a groove on the inside edge of the female fitting, the o-ring sits in the clear part in the middle of the threaded spigot. Then it's screwed into the female fitting up to that point and the knurled ring then tightes up to it and compresses the o-ring into that groove making it watertight, it allows the elbow to sit in any position throughout 1 turn of 360deg and still provide a seal.

 

[DIYspanner]

Got it!

So the o ring slot in the elbow is wider than the o ring itself so the elbow can be screwed in butting the ring to the spout then turned back slightly to the angle needed, then knurled ring tightened up to compress for a seal.

By the way, has a good seal now been accomplished on the job?

 

[Madrab]

Kind of ... the blank section in the middle of the male threaded fitting allows the o-ring to move up and down a little without being snagged on the threads. When the male section is screwed up in the female section, it's tightened up to that clear section, so when the knurled ring is screwed upwards, it grab the o-ring and presses it up into the groove in the female fitting, thus creating the seal. The width of that clear section allows a certain amount of movement to the elbow so it can be positioned where it needs to be withing 360deg without the o-ring being caught and damaged by the threads.

 

[Dhillon]

So thanks for all the advice everyone! I tried two rubber seals that seemed to fit but they both leaked, all be it slowly. In the end I used an oversized rubber seal that sits snugly below the female fitting (see pic), without going up into it. This has stopped the leak and all is good.
This really is a pita of a fitting and judging how far to screw in the rubber seal is a nightmare, to far and the threads cut the seal, and too less it will leak. Thankfully the solution I have now works and is easy to fit and tighten.

Thanks again all!