Toilet cistern fills when other toilet flushed

[tallg]

When I flush our en-suite toilet the cistern of the toilet in the family bathroom begins to fill and empty into the bowl. If I slightly pull up on the lever which I assume controls the water inlet valve, it stops. If I don't stop it manually it continues for 20+ min.

It used to only do this occasionally, but now it is every time we flush the en-suite toilet. I think sometimes it also happens when running a tap in either bathroom, but this doesn't happen often.

Any advice on what the problem is and how to fix it?

Many thanks.

 

[Agile]

many modern float valves use water pressure to hold the valve off.

It sounds as if your mains flow rate is very low and encourages further filling of the cistern.

I suspect that if you can lower the water level a little then that might solve the problem.

Tony

 

[tallg]

Yes, mains rate is low.

I will try adjusting the water level tonight and let you know how I get on.

Thanks.

 

[tallg]

No joy.

After flushing, the water fills to water fill line. But some time later it has risen to the top of the overflow pipe, so the float of the fluidmaster is now fully submerged.

 

[cozzmic]

Fit a low pressure red daiphram in the fluidmaster that should help.

 

[Charnwood]

Fit a low pressure red daiphram in the fluidmaster...

Fluidmaster only do the multi pressure washer nowadays. Search hard enough and you might find someone with some low pressure ones left.

 

[tallg]

Thanks for your responses.

Both toilets have a fluidmaster, but only one exhibits this problem. Does that suggest that the fluidmaster could actually be broken, rather than just a pressure issue?

I guess I could swap the two fluidmasters over and see if the fault moves to the other toilet...