On Dec 27, 4:18*pm, Ian Jackson
wrote:
In message , John
writes



"SS" wrote in message
...
I suspect the diagphram is on its way out as flushing getting less
efficient.

How do I know which size/type to purchase without dismantling the
mechanism.

When I do flush there still remains about 3 to 4 inches of water in the
bottom of the cistern, is this normal?

http://i64.photobucket.com/albums/h1...10003Small.jpg

As a comment I would suggest you slide the lifting arm forwards so it exerts
a direct lift upwards and doesn't strain stuff. Some water will remain as
once the siphon draws air in the column of water will collapse back into the
cistern.

Indeed. The lifting arm should give a straight lift. Why is it located
right at the end of the 'shaft'? It isn't, by any chance, that the rod
which pulls up the diaphragm was too long and, with the lifting arm
correctly positioned, doesn't lift the diaphragm high enough? If so,
shorten the rod (somehow).

However....
Once you've got the siphoning action started, it should keep going until
air gets in - which should be when water level in the cistern is almost
zero. If there are still 3 or 4 inches of water left, is air getting in
to the works and 'killing' the siphon prematurely? Maybe there's a split
in the cylinder or the inverted U-bend (especially at the top)?
--
Ian- Hide quoted text -

- Show quoted text -

Exactly why I never just change the diagphram. Very common to get a
near invisible split in the plastic moulding.

You can buy a new siphon for £5 from Toolstation & it takes the same
labour to change the diagphram as it does to change the siphon.

Dave