Toilet : intermittent problem : sometimes keeps filling up

[mamalovesmambo]

Hi,

I have a dual-flush close-coupled toilet that's about 5 years old.
For awhile now it's had an intermittent problem...
sometimes it won't stop filling up, so it overflows into the toilet pan.

I'm a DIY novice, but would like to have a go at fixing the problem,
rather than shelling out for a plumber to look at it.
I'm just not sure what needs replacing.

I've taken the lid off the cistern and had a look
it seems to be that sometimes the bit that gets pressed down when the toilet's flushed gets stuck and doesn't pop back up.
If I pop it up myself then the overflowing soon stops.

When I looked online, advice seemed to be saying that any "toilet overflow keeps running" problems were likely to be due to problems with the Ball Valve. But my inspection seems to imply there's problems with the flush-mechanism, not the filling-back-up-mechanism.

I'm just wondering where to start :
should I take apart the flush-mechanism first?
or the filling-back-up-mechanism ?

Any advice gratefully received!

 

[robertito]

Not sure, but maybe it needs a good cleaning. I think the mechanism can jam if it get a bit of limescale in the wrong place.

 

[mamalovesmambo]

Hi Robertito,

Thanks for your reply.
I doubt it's limescale, the water is very soft here.
So soft the kettle never ever gets limescale.

Any other ideas?

 

[JohnD]

(a) ...sometimes it won't stop filling up, so it overflows into the toilet pan...

(b) ...it seems to be that sometimes the bit that gets pressed down when the toilet's flushed gets stuck and doesn't pop back up.
If I pop it up myself then the overflowing soon stops.

You have to make up your mind whether (a) or (b) is true

You can post a photo if you like and tell us what you observe.

Also, tie up the ball-valve next time it does this, and see if the cistern drains itself, or keeps on filling up.