leak from bottom of cistern

[pcorpe]

OK, so first attempt, i've recently replaced the syphon on 2 wc's one works fine the other has a leak. its a close coupled unit (both are)

Fitted the syphon with the flat rubber ring on the inside of the cistern then the close coupling bracket then the large plastic nut onto the syphon thread, fitted to wc and wall, screws through top to wall of cistern, and the bolts tightened on close couple to pan of wc.

But now a leak around close couple mount? syphon instructions say not to use sealing compund... did i tighten close couple bolts too much, or did i not tighten plastic nut enough? leak is there all the time whilst water in the cistern.

thanks in advance

[RigidRaider]

Irritating, isn't it? I've got a leaking cistern as well but the water only drips just after flushing so I'm sure it's the joint. I'm avoiding doing anything until Saturday morning because I've learned never to undertake these jobs on a weekday evening - inevitably something goes wrong and you need to nip to the shops.

Sounds like you need to pull it all apart and investigate. At least the screws holding your cistern to the wall won't be rusted through and the wingnuts seized solid, like mine will be....

[micky p]

did you replace the big rubber donut washer that sandwiches between the cistern and the pan. It sounds like this is your problem. Take it apart and buy a new close couple kit from your local merchants and this should solve your problem. Also sometimes you can over tighten the wing nuts and bend the close couple plate down and cause a leak sometimes. Can be tricky at the best of times even for a plumber im afraid.

[Steady]

If water is leaking all the time it sounds like it could be the syphon washer not sealing. Best way to eliminate this is to remove cistern from pan, stand it on a couple of bricks etc then fill it with water and leave to stand- you will then see if it leaks or not .

Another problem can be that water gets past the doughnut seal if the pan is not level. This throws the cistern out of level aswell and you lose the seal at the doughnut- further tightening of the wingnuts will not help-the pan needs to be level. This will only happen when you flush but it leaves a pool of water in the recess where the doughnut sits and this then finds its way out at the lowest point .

[pcorpe]

Folks, many thanks for the suggestions, glad to see i'm not alone on this one.

the existing wc/cistern/syphon etc is only 2 years old, (it's a new ish house)
but the builders fitted the cheapest nastiest stuff where possible, we'd already had one of these replaced as the flush no longer worked as the diaphragm had ripped due to the amount of excess plaster and stuff left in the cistern, anyway i figured i'd give this a shot, so your right the screws weren't rusted and the wingnuts not siezed (have greased these now to try and prevent that from happening)

I had fitted a brand new close coupling with a new doughnut (nice rubber thing compared with the naff foam thing it replaced, which was already quite rusted)

so my conclusion from all your kind help is that it must be either the sealing rubber ring at the bottom inside the cistern, or i tightened the wing-nuts to much and caused a leak that way. so i will remove and check the syphon, but that leads me to another question, how tight should the wing-nuts be, is it a locating thing, can they be loose ish? seems odd to have a wing nut to enable you to tighten a lot if they should be loose?

thanks again

[RigidRaider]

Yes but I reckon you'd never tighten a wing nut with your fingers as tight as you'd do a nut/bolt with an 8" long spanner.

Being as it's a new house, are you sure it's not receiving cheap mains water? It's not as thick as the quality stuff and can find its way through the smallest gaps.

[pcorpe]

RigidRaider, yeah fair point given the choice i'd use a 3/4" socket set for eveything, but alias it's not the correct way i'm told.

the house, and the rest of the estate is not the best quality, some folks had hot water plumbed into their wc's! we just had 2 structural internal walls moved, so generally an interesting house, who know's what else is lurking that i can't see.

Yeah the cheap water thing would make a lot of sense, however we found flushing the toilets with neat bleach solves 2 problems in one....

[pcorpe]

so coming back to the original question, how tight should the syphon nut be?
instructions say finger tight and a quarter turn with spanner.

and how tight for the wing nuts, referring to earlier posts not so tight as the bend the coupling?

[RigidRaider]

If you own a 3/4" socket set it sounds as if you ought to be a competent spannerman so would be able to judge when a nut is just tight enough.

[Steady]

Syphon nut needs to be pretty tight, that's all I can say. Finger tight then a quarter turn doesn't sound anywhere near tight enough. If in doubt remove cistern and test for leaks![/quote]

[ChrisR]

Donuts are a problem, soft squashy ones are best - foam ones aren't bad at all.
Often the cistern doesn't sit on the donut properly. If you release the screws from the wall they often want to sit with an inch gap at the top - then they don't leak!
Big nut in the siphon has to be "pretty" tight. If you overdo it you'll know - the threads jump! You can fill the cistern and check that one if it isn't on the pan.
Wingnuts - plumbers fingers (stronger than average!) should do. I suppose I'd give a turn with a spanner too.
I have had to use two (foam) donuts, both cut to a wedge shape with a hacksaw.
One day somebody might make plumbing bits which fit together properly..!