Syphon's gone on cistern

Tigercubrider · 26 Mar 2019

Hi

I have a close coupled cistern and the flush has needed a 'knack" to get a proper flush for a while but recently it has been less reliable and last night gave up. I assume that it's toast? If the whole thing needs to come apart to fix a washer or flap, does it make sense to put in a new unit v a repaired 20 year old one?

Any recommendations for a decent brand or what to look out for? The handle is on the side and the connecting bar is parallel to the long side of the cistern if that matters.

It looks like this one - from memory - as I am at work now.

https://www.screwfix.com/p/thomas-dudley-ltd-turbo-88-siphon-9/8461f
Thanks

MeldrewsMate · 26 Mar 2019

It sounds/reads like the syphon flap valve has started to disintegrate. You can buy the flap really cheaply, but then have to dismantle the whole cistern to replace it! Better to replace the syphon with a two or three piece (top maintainable) syphon such as the one you linked to. Good to see you've selected one made in Britain - our children will thank you for it one day.
You will also need, in all probability, a new close coupling seal, plate, and fixing bolts, usually available as a kit for less than a tenner.

MM

robin7 · 26 Mar 2019

MeldrewsMate said:
You can buy the flap really cheaply, but then have to dismantle the whole cistern to replace it!

Actually, there would be no need to dismantle the cistern to replace the diaphragm - the Dudley flush valve separates into two parts for exactly that purpose.

MeldrewsMate · 26 Mar 2019

robin7 said:
Actually, there would be no need to dismantle the cistern to replace the diaphragm - the Dudley flush valve separates into two parts for exactly that purpose.

There is that possibility, but then the OP stated that the link 'looked like this...from memory'

Hugh Jaleak · 26 Mar 2019

If there's already a Turbo syphon in there, split it and change the washer. If not, the old syphon will need to come out to replace the washer, your call, but if keeping the WC for a while yet, might pay to fit a Turbo syphon for future purposes. Personally prefer syphons to the new flush valves, as a syphon can be repaired, flush valve usually needs changing complete.

Bosswhite · 26 Mar 2019

If its a Turbo Syphon it will be easy to change the diaphragm if not it means removing the cistern as explained above, I personally would go for a fluidmaster Flush valve as they are simple to replace in the future, if you have to strip the cistern down replace the filling valve with a fluidmaster with brass shank again life will be easier in the future to adjust it .

Harry Bloomfield · 26 Mar 2019

Tigercubrider said:
Hi

I have a close coupled cistern and the flush has needed a 'knack" to get a proper flush for a while but recently it has been less reliable and last night gave up. I assume that it's toast? If the whole thing needs to come apart to fix a washer or flap, does it make sense to put in a new unit v a repaired 20 year old one?

Any recommendations for a decent brand or what to look out for? The handle is on the side and the connecting bar is parallel to the long side of the cistern if that matters.

It looks like this one - from memory - as I am at work now.

https://www.screwfix.com/p/thomas-dudley-ltd-turbo-88-siphon-9/8461f
Thanks

I have the 9L version installed in two toilets here, of that model and at first I could not get the reduced flush to work reliably. Both were installed new, to replace some older flush units. Enquiring with Dudley they suggested the fill valve was set too fill to too high a level. It would sometimes flush at reduced sometimes not, by holding the flush handle down. A workaround was to press the handle twice and hold it down at the second press, where it would work reduced every time.

Reducing the fill level helped a little, but didn't completely fix it, besides reducing the level reduced the effectiveness of the full flush - meaning it would sometimes requires several full flushes to clear the bowl. Both units have the same issue.

Has anyone found a fix, or found that their 88 works as designed on the reduced flush please?

Hugh Jaleak · 26 Mar 2019

Only thing I can think of is are the plugs seated correctly in the reduced flush holes? It relies on drawing air in through these holes to break the syphonic action and stop it flushing.

Tigercubrider · 28 Mar 2019

OK

so I have managed to remove the siphon and it's the type that allows you to replace the flap and not disassemble the whole thing.
Replacement kit ordered from Screwfix
I did find "Dudley" on it.

Thanks in advance (fixing it tonight)

Tigercubrider · 30 Mar 2019

Ok.
Turns out I ordered the wrong kit, plus somehow ordered two!
The membrane/flap was torn and a different shape to the one in the kit.

As I didn't have any thick polythene to hand I found an unused "toastabag" that is intended to make toasties in a pop up. They are a flexible material like silicone baking sheet so 5 mins with some scissors and a few location holes punched, job done.
Hopefully it will last a while

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Syphon's gone on cistern

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