Toilet siphon problem

[truemanufan]

Was at a mates house this morning and he has replaced his siphon in the toilet cistern as the previous diaphragm was split. The problem is that the new one won't get any suction to flush the toilet? Never seen a problem like this before? Really puzzled! I have included a pic. Not that its a good one ha ha

 

[JCplumb]

Looks like there's not enough room for that size of siphon. Looks squished up against the wall of the cistern. If that's the case then the diaphragm won't be lined up with the bottom of the siphon casing. I'd go for a flapper type in such a small cistern tbh. There's a fluidmaster one in screwfix for £12 atm.

 

[dave1]

Water level set correct?

 

[petercj]

Is the diaphragm lifting fully when the handle is turned - there doesn't appear to be a screw in the arm that links the handle rod to the siphon, so could it be slipping?

 

[truemanufan]

Yeah the diaphragm isn't lifting too good but he did say that he replaced it with a slightly larger one. Thanks for the help

 

[glenno1]

Diaphram may need cutting to size

 

[petercj]

They're so cheap I wouldn't have thought it was worth patching up...

Opella Dual Flush Siphon | NoLinkingToThis

 

[snowhead]

Yeah the diaphragm isn't lifting too good but he did say that he replaced it with a slightly larger one. Thanks for the help

You can't use larger one, there has to be enough room for the diaphragm to give way and let the water past.
It needs triming to about 3mm over the size of the plastic support, or ideally to exactly the same size as the old one.

 

[dsteves619]

C link looks ****ed, make sure it pulls up vertically and not at an angle.

 

[truemanufan]

Ok thanks for all the feedback. Still a bit confused as to why the lad has bought a larger siphon for the cistern? Seems a bit mental. But all shall be fine come Sunday afternoon

 

[Resolute]

Rip it out and stick in a flush valve - job done!