I have now solved the poor flush problem and have described below my original message how it was done, should anyone be interested or anyone having a similar problem be searching this newsgroup
Track on down
---- Original Message ---- From: "Jen D" Newsgroups: uk.d-i-y Sent: Sunday, November 04, 2007 1:23 PM Subject: Poor Flush
Hi
>
> It was apparently working fine - then an overflow problem - now it
> doesn't have sufficient siphonage to take away a piece of toilet > tissue! >
> It's a close-coupled toilet (25+ years old) which originally had a
> problem with its overflow. A friend of my mothers replaced the
> existing toilet siphon with a push-button flapper toilet cistern
> valve, which incorporated an internal overflow - solving the overflow
> issue. However, now it has a poor/weak flush.
>
> When the toilet is flushed, water seems to emanate normally around
> the bowl rim, the bowl water level rises and then returns to its
> normal level but with no particular siphon whoosh, which results in a
> simple test piece of toilet tissue remaining in the bowl.
>
> The only things which jumped out at me (I don't mean that literally)
> when I looked in the tank was that the water level was lower than the
> waterline mark on the inside of the tank (approx half the depth), and
> the bottom entry inlet valve looked quite short.
>
> I have tried holding the float down to allow the tank water level to
> raise to the waterline mark (which takes the water level over the top
> of the inlet valve) - this produced a more significant flush which
> took away the toilet tissue, but I doubt that it would have taken > away much else. >
> I have checked the external drainage which appears free flowing - the
> only other thing that crossed my mind was whether a plastic toilet
> bowl blocks which should hang off the rim has fallen into the bowel
> and become trapped in the bowl siphon. Although, Im leaning away from
> this as it would have thought the issue would have been apparent
> prior to the flush mechanism change.
>
> I have also tried tipping a bucket of water into the bowl which
> seemed to result in better bowl siphon.
>
> I beginning to think that the problem is associated with the
> 'quantity and speed' of the water entering the bowl and intend to nip
> to my mothers to have a closer look at the rim holes to see if they
> are restricted in anyway and also look to see if the flapper can be
> adjusted in anyway.
>
> Does anyone have any other thoughts?
>
> Thanks
Well, it wasn't the rim holes nor anything in the trap or any other type of blockage. So I decided to go to my local DIY store and have a closer look at the packaging for the push-button flapper toilet cistern valve, installed by my mothers friend, to see if the flapper could be adjusted in anyway. However, reading the packaging I came across a warning note which said "this product cannot be used with a double-trap system" - this got me thinking!
I then did some research on the net and found that my mothers toilet was actually a "close coupled, double-trap, syphonic pan" (1970-1980 manufacture).
Digging around a bit further I found references indicating the need for an "aspirator" or "bomb". Initially, I had no idea as to what these looked like or how it fitted into the system. However, eventually I found a section on a web page for a similar product (airex fitment) which allowed me to at least visualise what the aspirator was and how it was incorporated into the system. Once I had this I could see why the installed flapper toilet cistern valve would not work and now guess that my mother friend likely chucked-out the original aspirator thinking it was part of the originally installed syphon, which he replaced.
formatting link
little bit more digging around and I found details of an aspirator which fitted into the end of a cistern syphon.
formatting link
eventually tracked one down to my local Toolstation, (my local plumbcenter and a couple of other plumbers merchants I tried didnt have one) and only £14.
formatting link
had also gathered from what I had read on the net, that the aspirator did not fit ALL syphons, it did however fit the Dudley Turbo 88 (complete with internal overflow), which I pick-up from my local Plumbcenter
formatting link
and install of the new syphon and aspirator was pretty straightforward and results in a perfect flush (and being double-trap syphonic - a very quiet flush)