Dual flush valves - what principle do they operate on?

[TerryWaite]

Hi

I want to know what principle/ mechanism dual flush toilet valves use to flush. i.e. what is actually happening when you press the button and how does it control a short flush or a full flush. I know how the siphons in older style toilets work, but there seems to be more and more of the dual flush units nowadays. And also, what is the correct name? Dual flush valve?

I am commercial mainly, so I wouldnt say I was a genius at plumbing,

I have been doing more and more bathrooms recently, and am starting to get alot better at setting out, forseeing the potential problems, overcoming them, and giving a nice finish. I have to go back to one though as one of the aforementioned flush valves is not giving a good flush, not taking the paper down sometimes. Is the only adjustment on these the slider on the side? And adjust the water level in the tank. What else can I do to try and get a more powerful flush?

It is a close coupled WC.

Cheers

 

[PlumbBobBob]

if you have a look at the flush button(disconnected of course) and press one of the buttons then the other one, you will see that one has a longer bit that pushes out than the other. this is what makes the two levels of flush, long and short.

 

[plumber0808]

It should just be a quick adjustment of the water level.

It will have some sort of mark line that indicates where the level should be to give 6 litres.

 

[Simon F]

as said, check the water level and flush controls.
But also, check that the water is leaving the toilet as it should.
a blockage there would also cause issues

 

[lame plumber]

nowadays we have limited water to flush with and it just isnt working properly! the only way to boost your flush is more water in the cistern or best of all, high level cistern, funny how the old ways seemed to work best!

 

[rpm]

Have found on the odd occasion that when there is a macerator as well sometimes slightly less water cures the problem. can only think it`s something to do a vortex, anybody out there know the answer?