cistern 2 part syphons

[stuart noble]

I need to replace the syphon on a close coupled WC. To avoid having to remove the cistern again in the future, I'll probably install a 2 part job. Seems like the choice is between the Macdee Metro and the Dudley Turbo, but both come in a variety of heights from 7.5" up to 10.5". I'll measure the old one, but how crucial is it? Do you use the tallest that will fit in the cistern or does the position of the handle come into the equation? With so many different types available, maybe it's better to go for something that isn't two part, but is likely to be more reliable than the diaphragm type. Comments appreciated.

[<me9]

I have a flapper valve in mine, not very reliable, so I'm thinking of going back to a syphon. I'm wondering how the height is measured. Is it the external height, or to the overflow, or to the flush level of the syphon?

[stuart noble]

There are diagrams here

[Bob Mannix]

If it incorporates the overflow, that sets the maximum height (as the overflow has to be low enough).

[<me9]

Thanks. Looks a useful site (didn't look at prices though). bookmarked.

[stuart noble]

Thanks. This cistern has an external overflow so I assume the height isn't as important. I can't imagine the average merchant stocking 5 versions of the same syphon, so I may have to take the closest available.

[The Medway Handyman]

I change quite a lot of syphons & just pick up a 'bog standard' :-) 9" one in Wickes or B&Q. That seems to fit everything.

[stuart noble]

Not 2 part though. I like the idea of being able to change the diaphragm easily as that's what always seems to go. Not a good idea for the plumber of course :-)

[The Medway Handyman]

Agreed of course, I was just saying 9" fits everything. Oh err missus.

Given the £2.49 for a diaphram & the £12 for the entire syphon - and the same labour cost for fitting both (in a basic syphon) I always change the entire syphon.

I've twice changed diaphrams on old syphons only to find it didn't sort the problem - there was a small split in the plastic syphon body both times.

[stuart noble]

But a longer job on a close coupled WC, with the possibility of having to replace seals and maybe rusted bolts etc. The Metro 2 part version is £12 inc delivery from BES.

That's interesting. I've always assumed it's been the diaphragm that's gone but never bothered to check before chucking it. There must be good reasons why local merchants don't seem to stock the 2 part, serviceable version. I'll probably find out after I've fitted it :-)

[John]

Having never had a diaphragm failure - how long do you think they last?

[stuart noble]

Until you next have guests staying overnight :-)

[The Medway Handyman]

Dunno. Years & years I guess. What tends to happen is that a small tear will cause the loo not to flush first go. People then tend to pump the handle up & down vigorously to get a flush & the extra strain causes the diaphragm to fail completely, or the hook to come off the handle, or the handle to become loose.

So, once they start to go, they go from bad to worse rapidly.

[The Medway Handyman]

No, I meant if the diaphram is gine on a standard syphon, you might as well change the lot. You have to take the syphon out to change the diaphram.

You do see diaphrams that don't seem too bad. What I reckon is, at the first sign of non flushing, the punters start pumping the handle which causes strain on the syphon.

Anywho, after 2 call backs I chage the lot now.

Do let us know :-)

[Alang]

I changed one that was rotting. Slimy and falling apart in my hand. I blamed those cleaning blocks people put in the cistern.

[Appin]

The message from "John" contains these words:

Depends on how incontinent you are!