Slow refilling toilet cistern

[u0362565]

Hi all,

My slow filling cistern is starting to bug me and would like to investigate why this is so. The cistern as I understand is refilled from a header tank in the roof space above the bathroom. I'm reluctant to start turning too many taps off considering I don't really know what they're controlling but there is a copper one next to the toilet which then links to the cistern inlet so assume if I turn off this tap it will stop the cistern refilling? It's potentially years since this tap was touched so hoping I don't have to put too much pressure on it to close/open. Could it be the flow to the cistern inlet from the header has been set too low purely by how open/closed this tap is? Is there a reason why it wouldn't it be set fully open? If it's not that I suspect an issue with the valve in the cistern itself but for that I need to empty the cistern first to avoid a flood?

Thanks for the help!

 

[Best]

Could be caused by the washer inside fill valve is swollen or dirt blocking it or wrong 'nozzle' part fitted (high pressure but should be larger bore low pressure) if it is a standard ball valve type. The diaphragm washer on part2 valves expand out with age and restrict the flow.
Some of more modern valves have filter inside them could block easily.

 

[u0362565]

Ok thanks for the info. I assume this washer is located at the base of the stem of the fill valve where the stem connects to the inlet?

 

[SimonG]

Or its a siamp with a split diaphragm.

 

[Howsie]

Ok thanks for the info. I assume this washer is located at the base of the stem of the fill valve where the stem connects to the inlet?

No, it's near the top where the water comes out.

 

[clemda1]

If its off a header tank then my guess it's just the diaphragm on the float operated inlet valve that has perished. Very simple fix. But you will need to isolate the water supply prior to replacing it. Lots of you-tube videos on replacing these. But only attempt it if you can safely isolate the water supply from the header tank. There should be gate valves coming off the tank or local service valve. If not then you'll have to drain the whole tank after tying up the ball valve in the tank. But this could lead to air locks.....