Toilet cistern makes noise when flushing

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Hi

Does anybody have any idea why when flushing the toilet it makes a load kind of humming/vibrating noise? I seem to have traced it back to this item in the cistern?

It does not always happen, but when it does if you hold down the flush again it stops the noise.

Also when flushing even when the cistern is full it does not always flush, the same as it only makes the noise intermittently?
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The noise will be water hammer, possibly due to worn float operated valve and/or unclipped pipework.

The lack of flush will be due to a faulty syphon, probably split diaphragm.
 
Hi Mike

Thanks for the quick reply

Is the worn float operated valve what I circled in red in the pic? If so how much are these to but and are they difficult to install (how much would a plumber charge)

With regard to unclipped pipework with this do you mean the actual pipework feeding the toilet with water? As there

Finally you mention faulty syphon, probably split diaphragm where in the cistern is this and again how much would it cost to remedy the problem and does water hammer if this is case cause any damage?

Many Thanks
 
Water hammer is quite often due to wear on a float operated valve (thing with the arm on) but is exacerbated by unclipped pipes transmitting the vibration and noise. If the cold water is tank fed it could also be the valve feeding the tank in the loft.

The syphon is the big plastic bit in the middle. When the toilet is flushed a large polythene diaphragm lifts the water up and starts the syphonic action. If this is split it will require two or three pumps to flush.

Severe water hammer can cause damage to pipes and fittings if left for long enough.

Replacing both is well within the scope of a competent DIYer but if you're unsure ring a couple of local plumbers and asked them for a rough idea of price to change them. You can find both components on screwfix.
 
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Thanks Mike

We had a new central heating system installed last Feb - and had the old galv tanks in the loft replaced with one cold water tank where a feed comes off (which is the original run) and I think it runs to the cistern
 
Get yourself a Fluidmaster fill valve and flapper valve.
Any fool who can handle a spanner can fit them. I did. ;)
 
Thanks so the fluidmaster valve would replace the

worn float operated valve ?

And the flapper valve would replace the faulty syphon?

Do you have links to the products I need on screwfix please? so I can go and pick them up tommorrow

Many Thanks
 

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