Cistern won’t fill/fills really really slowly

Boscoirl

Hi All,

The cistern on the toilet is as good as not filling up. Might fill enough to flush after an hour or so.

It is a fluid master 400 (linked below)
https://www.fluidmaster.com/united-kingdom-products/fluidmaster-pro-series/pro400uk-pro-bottom-entry-fill-valve/

It happened brefore and it turned out to be an airlock on the supply from the tank in the attic.

Had a look in the attic and the tank was full and the feed to that is not reduced ( good flow when you press down on the ballcock)

I removed the red cap to let the water flow into the cistern ( carefully avoiding the water going everywhere) to see if that would flush the airlock out. But it still fails to fill when I replaced it.

It looks like the seal is staying closed and preventing the water from entering even when the lever/float is pressed down to open it as much as possible.

Would replacing the seal sort this out?

At the moment I have the seal removed and using the cut off valve to manually fill it.

wizardman

Boscoirl wrote: »

Hi All,

The cistern on the toilet is as good as not filling up. Might fill enough to flush after an hour or so.

It is a fluid master 400 (linked below)
https://www.fluidmaster.com/united-kingdom-products/fluidmaster-pro-series/pro400uk-pro-bottom-entry-fill-valve/

It happened brefore and it turned out to be an airlock on the supply from the tank in the attic.

Had a look in the attic and the tank was full and the feed to that is not reduced ( good flow when you press down on the ballcock)

I removed the red cap to let the water flow into the cistern ( carefully avoiding the water going everywhere) to see if that would flush the airlock out. But it still fails to fill when I replaced it.

It looks like the seal is staying closed and preventing the water from entering even when the lever/float is pressed down to open it as much as possible.

Would replacing the seal sort this out?

At the moment I have the seal removed and using the cut off valve to manually fill it.

Sounds like the diaphragm washer is gone hard. Needs to be replaced. You've confirmed it's not airlock or blocked with debris.

Boscoirl

Thanks for the reply!!

Will pick on up tomorrow and give it a try.

Glen Immal

Had a similar issue, bit of grit in the ball cock valve....