Toilet cisterns overfillling

[HumpyD]

Our 2 upstairs toilets have recently started to overfill meaning that the toilet constantly flushes. One of the toilets is worse than the other in this respect.

I have looked in the cistern and it looks as if the valve is a Torbeck type but probably not an actual Torbeck valve. All I can see on the valve are the words "Quiet ballvalve".

Firstly is it worth trying to replace the diaphragm by undoing the retaining nut with a 'proper' Torbeck item? Should I be replacing the float too?

Or should I simply replace the whole unit with a Fluidmaster Fill Valve as is what we have in our downstairs WC and which gives us no issues? If this is the best course of action, is this easy to fit by a DIYer?

Thanks.

 

[PrenticeBoyofDerry]

First check when you lift the float up, that the inlet valve close and water stops.
Then check that float is set in the correct position to close the inlet valve, rather than dumping water out of the overflow. I would be surprised if this is a diaphragm problem.
Very likely to be float setting or faulty inlet valve.

 

[JohnD]

IME this type of valve is prone to clogging with grit, rust or limescale fragments in the water.

Turn off the supply, take it off, dismantle, wash it out in a large glass mug or dish so you can see what comes out, reassemble with care (look out for a metal needle).

If there was dirt, turn the water back on to flush out the supply pipe before you refit the valve.

It often happens after work on the plumbing or watermain has disturbed sediment.

 

[HumpyD]

Thanks for your replies.

Oddly when I raise the float by hand to the horizontal position (i.e. the approximate fill level of the cistern) the water doesn't stop.

Something else that seems to be connected is that this happens more when the water pressure to the may be lower because of the central heating pump being on, other taps on, etc. Does this mean anything?

 

[JohnD]

Oddly when I raise the float by hand to the horizontal position (i.e. the approximate fill level of the cistern) the water doesn't stop.

Clean out the grit.

 

[PrenticeBoyofDerry]

As above, sounds like debris has got in to the mechanism if the valve does not close.

 

[HumpyD]

Thanks John.

I'll try that over the weekend!!

 

[HumpyD]

Thanks also PBoD.