Toilet not flushing well, may be syphonic

[IJWS15]

Just moved into a 1980s house which has three of these.

One is playing up and helpfully is tiled in so not sure if I can get the cistern off. Doesn’t seem to be related to pan contents but are parts still available - it is marked Ideal Standard.

 

[IJWS15]

Got a bit further and took the cistern off, no bomb!

Would that explain why it sometimes doesn’t flush?

There is also no hole for the bomb to feed - if I ever find the guy that boxed it in………… there is about 20mm between the tiles and the bottom of the cistern.

Do I just replace the big rubber ring?

 

[Hugh Jaleak]

Better to start your own Thread, (will ask if Mods can move your question.)

What makes you think you have Siphonic Pans?

 

[IJWS15]

I have seen siphonic pans before but not had to take one apart. Parents and grandparents (as a six year old theirs fascinated me) have had them and these behave in exactly the same way. When flushed the pan fills slowly and a swirl is generated as the pan contents disappear, at the end of the flush the level in the pan drops to le level of the lip in the ceramic before refilling a little. All three behave the same way. The pans are quite long.

 

[IJWS15]

I think I have worked it out, doesn’t appear to be anything to do with the siphon in the pan but the siphon in the cistern.

Air is leaking into the siphon through the hole that the plunger moves through in sufficient volume to disrupt the siphonic action so flushing only uses about 1/3 of the water in the cistern. Combine that with the convoluted siphonic pan and it can block. If I lift the handle when it starts to flush it reduces the air leakage and the flush is longer.

Just have to train the wife to do it!

 

[Hugh Jaleak]

Sounds like you have a Dual Flush Siphon, half flush, press handle and let go, Full Flush, press handle down and hold until cistern is empty.

If you do have a siphonic pan, (photo of pan, sideways on would tell us more), then it needs the full flush to work correctly. Someone has replaced the siphon in the cistern at some point and fitted a Dual Flush type, may be able to seal the air hole with a plug if you can find one, or just change the siphon .