side flow fill keeps flowing

[athlonoc]

Hi,

I have just installed a brand new side fill concealed cistern.
The cistern fills ok and gently stops an inch below overflow. The float then stop moving up as expected.
All seems ok until about 30 to 60 seconds later the outlet slowly starts to drip water which then becomes more steady and then the float starts to move down increasing flow until it goes over the overflow and then just continues to fill and out into the pan.

Before I take the side entry fill valve out and replace with another new one is it likely that it's faulty or am I missing something?

Thanks

Lee

 

[snowhead]

It may just be grit or other contamination in the valve, worth cleaning it out first before total removal.