Aqualisa Class 200 Inlet Elbow question

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Hi there. I have an ancient Aqualisa Aquavalve Classic 200 mixer shower. It's been in service for around 30 years and, apart from a couple of cartridge replacements over all those years, it has (and continues to) work fine.

However, after those ~30 years, a (fairly small) leak has, for some risen, arisen from the (cold, 22mm) inlet elbow. Although it is installed 'concealed', thanks to some forethought on my part 'way back', I have access to the plumbing from the other side of the wall, so my tiles can remain undisturbed!

I have removed the elbow in question (getting the grab ring off was, as others have observed, a significant fight!) and I really cannot see anything wrong with it - in particular, the O-rings look fine.

Anyway, I've obtained a replacement elbow, but there's one aspect of it which surprised me - but very probably unnecessarily. The photo below shows what I've got

Inside of the inlet end there is just the grab ring and, upstream of that, the O-ring. Am I to understand that the only 'sealing' is that achieved by the O-ring being 'squashed up' against the inside of the housing? What had/has me a little confused is the purpose of the screw-on 'end cap' (like a compression fitting back-nut - bottom right in photo belkow) since, even if one screws it on as far as it will go (until it hits a flange), it does not tighten against the O-ring -so I wondered whether there was perhaps a further washer (or something) missing that was meant to go between the cap and the O-ring?

I suspect that I've just over-thinking this, and that if I simply push the pipe into the fitting ('as far as it will go'), and then just do up the 'end cap' (whatever its purpose!) hand-tight, all will probably be well - but it would be good to have some reassurance (or the contrary)!

Thanks. This is what I have ...

upload_2021-6-15_0-43-18.png


Kind Regards, John
 
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CBW

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Hi John,

looks similar operation to a speedfit push fit fitting, it’s the grab ring that prevents it from pulling out and the o ring to seal with the aid of the nut. It also has to be pushed fully home before sealing correctly.
 
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Hi John, ... looks similar operation to a speedfit push fit fitting ...
Thanks for your interest.

Yes, it does, with the one major difference that a Speedfit fitting does not have a removable 'nut'.

I can understand why there has to be 'something' like the nut. The grab ring is not attached to the body of the fitting in any way so, without the 'something', water pressure could just push the pipe (complete with grab ring and O-ring) out of the end of the fitting. However, for normal use that 'something' does not need to be removable (one could insert the pipe with the nut 'fully screwed on), and therefore could be glued/welded/whatever onto the body. I can but assume that it is made 'unscrewable' either for manufacturing convenience and/or so that one can dismantle the fitting (e.g. to replace the rings).
.... it’s the grab ring that prevents it from pulling out and the o ring to seal with the aid of the nut. It also has to be pushed fully home before sealing correctly.
It's the bit I have highlighted there which was slightly concerning me since, as I said, it is not possible to tighten the nut onto the O-ring - there is still a (very small) gap between nut and ring when the ring is screwed fully on (which is why I wondered whether I was missing some washer/spacer which was meant to go between O-ring and nut). However, I suppose that water pressure will result in the grab ring pushing the ring into tight contact with the nut, even though one cannot achieve that by tightening the nut.

Anyway, do I take it that it's OK for me to just fit what I have (i.e. push the pipe in as far as it will go and screw the nut on as far as it will go)? My concern was that, if I were missing a washer/whatever, I did not want to get as far as the gab ring 'grabbing' the pipe before realising that I had to dismantle it to add the missing bit :)

Kind Regards, John
 

CBW

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Yes you can just fit what you have. FYI most speedfit (as in John guest speedfit) are demountable. It’s more th white hep2o fittings that are solid with no thread. I doubt there’s anything missing, so it’s a case of trying it really.
 
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Yes you can just fit what you have. FYI most speedfit (as in John guest speedfit) are demountable. It’s more th white hep2o fittings that are solid with no thread. I doubt there’s anything missing, so it’s a case of trying it really.
Demountable, yes, but, as far as I am aware, no way one can unscrew anything to get at (and potentially replace) internal components (like O-rings), nor anything like a nut which one can 'tighten' to create a seal with the O-ring (as you suggested with my fitting).

Whatever, it sounds as if, as you say, I should just 'try'! Having said that, there has been a slight new development in the last half an hour! I have just 'found' the plastic/nylon flat washer depicted at the bottom of the photo below, which may well have 'fallen out' of the old fitting when I was fighting to get the pipe out of the grab ring. Despite the slightly misleading appearance in the photo, it is exactly the same size as the O-ring and, if fitted between O-ring and nut, does allow the nut to be 'tightened onto' the ring. No such washer came with the new fitting (only the grab ring and O-ring). On the face of it, I don't see that it could do any harm, so I'm tempted to use it - what do you think?

upload_2021-6-15_20-44-40.png


Kind Regards, John
 
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Speedfit can be fully disassembled.
Do it all the time, to rob bits out of one fitting to put in another, even to the point of easing off grab rings to re-use.
AQL is no different.
In summary, if it don't leak, the joint is sound!
 
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Speedfit can be fully disassembled. Do it all the time, to rob bits out of one fitting to put in another, even to the point of easing off grab rings to re-use.
Fair enough. I was certainly not aware that that was possible, probably at least partially because I've never tried - but now you have put the idea into my mind, I may well 'do an experiment' :)
In summary, if it don't leak, the joint is sound!
Very true. However, as I wrote to CBW, I wanted to try to avoid the possible situation of finding that it did leak, because I had 'missed out a part', after the grab ring was doing its grabbing!

Kind Regards, John
 
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