WC internal overflow syphons

[JonMcD]

I replaced our toilet syphon with a drop valve type flush some years ago, and disconnected the external water overflow warning pipe. However, the drop valve stuck open a few days ago and as we are on a water meter I have decided to go back to a syphon.

Looking at the descriptions of syphons for sale I see that some claim to have an internal overflow. This is what I need but surely any syphon provides an internal overflow as long as it is installed with the internal spill-over height well below the level of any unsealed holes in the cistern.

Is the internal overflow claim for these syphons just marketing hype, or have I missed something and they really are different in some way?

JonMcD

[YAPH]

It's not marketing hype but the difference is they're shorter - 7" rather than 9.5" or thereabouts (off the top of my head)

[Skipweasel]

Not sure I could spare 9.5" off the top of my head.

[YAPH]

"New" in geological time :-)

In days of yore, operating

Au contraire, I think it would work

The problem I find with

On the other hand a badly placed overflow/warning pipe can be pissing away for ages without being spotted - particularly during winter if people don't go wherever it's located.

[Mike Barnes]

harry :

Didn't we discuss this some years ago? I came to the conclusion that you can divide the population into two groups: those that would never notice, and those that can't fail to notice. With a female/male bias, for fairly obvious reasons.

[chrisj.doran]

The problem I see is when you have both a blocked loo and an overflow. And don't anyone suggest that Murphy doesn't have that one well in hand :-)

Chris

[Andy Dingley]

Our university bogs (1960s building) couldn't be ignored. The overflow was central, external and didn't require outdoor plumbing as it was mounted conveniently over the sitter's head!

Worst of all was our house in N Ireland. Cistern on an inside wall, so the plumber (an inbred halfwit with vestigial gills) merely led it into the cavity and stopped there!

[John Stumbles]

Well that would solve the 'not noticing it' problem ;-)

[JonMcD]

answers my original question, at least for Delchem Dualflush Siphons. These come in 7½?, 8?,

9?, 9½? heights and they say you get the internal overflow feature by buying the correct height syphon for the cistern.

What caused me some doubt originally was on-line shops who repeat the internal overflow claim for Dualflush Siphons but don?t stock the smaller sizes or only stock one size.

JonMcD

[The Medway Handyman]

I've found these to be very easy to install & adjust & they seem very reliable

also do a 'leak sentry' version which I have never fitted, but seems worth a look.

[JonMcD]

Thanks for the suggestion, but I've gone off cable operated flushes. It was the cable sticking that stopped the drop valve seating in the first place. We have hard water and I assume limescale build-up on the cable was to blame since once I'd taken it out and operated it a few times it freed up. Think I'll stick to lever operation from now on.

JonMcD

[YAPH]

Didn't follow the link but if it's the fluidmaster flap valve the one (first and last :-|) I fitted was bloody fiddly.

[The Medway Handyman]

Flap valves are OK for furriners I spose, but agin nature & no good will ever come of them...