Fitting a dual flush system

[btb23]

As we're on a water meter it's been on my mind for a while to convert the toilets to dual flush. A bit of research reveals two options, either a syphon or drop valve.

So I've found these two items Duoflush or Drop Valve, and wondered if the experts have any advice. The Duoflush is more expensive, and keeps he existing handle, and maintains the syphon, but I'm not sure if it's adjustable.

The drop valve uses a push button, which I like the idea of, and seems to be adjustable in terms of the volume of water used on each type of flush. It's also very reasonably priced and made by Opello, a good company making quality products and excellent customer support if it goes wrong. (I had problems with a Torbeck and they were extremely helpful).

I'm tempted to go for the drop valve, but as they've only recently been allowed for use in the UK I'm wondering what the advice may be. I'm thinking the problem might be that if they leak water dribbles down the pan, undoing any saving that the dual flush is giving. So anyone have any experience with them?

 

[Nige F]

Drop Valve But I wouldn`t bother until existing syphon packs up. Even down here in Rich South The water is good value ..compared to the rates we used to pay before the whole town was metered. The water co. actually shot themselves in the foot

 

[TicklyT]

When a syphon fails, it usually doesn't flush at all.

When a drop valve fails, you usually end up with a constant flow of water into the pan.

Older WC pans were designed to use about 9 litres of water for each flush. Modern ones are designed to flush efficiently using about 6 litres of water, or less for a short flush. If the reduced flush volume isn't enough to clear the pan, you could end up flushing it twice anyway, using, say, 2 X 6 litres instead of 1 X 9 litres of water.