noisy siphon

[apcdave]

Today I fixed a leaking cistern - usual sort of job, took cistern off wall, replaced the " doughnut " - all seems fine and leak free but ...... when the the flush mechanism is operated ( push button type ) , it flushes ok but there is an audible " thump " from the siphon I assume - just wondered why this should be and if it can be rectified ? As i said it is working fine and not leaking which is i suppose the main thing

many thanks,

dave

 

[Jason.S]

I have a Roca c/c WC and it does exactley they same.

Irritating but works fine.

I suppose it depends on the make of flush mech?

 

[Dave]

It could be the cold feed to the cistern..if it is not clipped it can vibrate and give that thud sound....mine did it till i clipped the pipe to the wall...( plastic pipe)

 

[Puddle]

To stop 'thump' from syphon turn flow though ball valve down,the cistern is filling to fast

 

[MarkB]

If it's a push button flush then it's likely to be a flush valve and not a syphon. I've had a few of these close very noisily when the flush finishes.

I still haven't found a way of making them close more quietly.

Mark

 

[REDSAW]

agree with mark, its caused by vacume i think, as the syphon lowers it sticks slightly then jumps on when the suction overtakes. try a bit of tungston putty (lead) to ballance it.