Leaking Flush

[Nigel Watts]

The loo in my modern side extension has been seeping an evil looking liquid at floor level for so long that it has come to resemble a Francis Bacon painting.

When my wife was away last weekend I finally summoned up the courage to tackle it (I have an aversion to plumbing jobs). Being architect designed the cistern and associated plumbing was all hidden away behind panels, and I guess like most such arrangements, when I finally managed to open it up everything behind the minimal modernist casing looked very jerry-built but I was relieved to discover, contrary to my fears, that the problem lay with the flush not the waste and the rot which has attacked some of the woodwork and mdf doesnt look too serious (it could have a touch of the dry rot but there is no structural timberwork anywhere near, the floor being made of concrete beams laid across concrete foundations)

I have now replaced the "flush cone" - the seal in the back of the pan - which has fixed 90% of the problem, but the plastic pipe joint directly under the cistern still drips a bit. What is the best way to fix this? I tried unscrewing it, smearing it with lard, and screwing it up again, but this has not worked. The rubber ring seal thing looks undamaged, but should I try replacing it? Is there likely to be another cause?

By the way, the unsightly turd-coloured but rock hard deposit on the tiled floor round the base of the loo responded magnificently to the application of full strength Spirits of Salt, disappearing in minutes, sizzling away and giving off thick clouds of Chlorine gas (I only later read the instructions on the bottle, which advised never to use it neat - what spoil sports!).

 

[FamilyWiggs]

Things to try:

* replace rubber seal
* tighten large nut inderneath cistern with plumbers wrench as tight as you can (care not to crack cistern)
* drain and dry cistern, smear silicone sealant between rubber seal and cistern and cistern and nut, retighten and refill

HTH

Robin

 

[Feltwell]

I'd echo what Robin says, but for a sealant try Fernox LS-X

http://www.screwfix.com/search.do;j...ACSTHZOCFFI?_dyncharset=UTF-8&fh_search=23614

Sold at B&Q as well. Take connection apart, smear sealant on as appropriate, re-assemble but be really careful not to over-tighten the connection.

Good thing with this stuff is that it never sets hard - it doesn't crack with age and you can get joints apart again in the future.

 

[wombat]

I fitted a complete toilet system outside,had a leek where the pipe joins the cistern i tried all sorts--answer in this case PTFE tape on both threads inside and outside (plastic pipe and nuts)
T

 

[MdB]

Ditto Fernox or PTFE. Silicon will probably fail after a while.

 

[FamilyWiggs]

Yes agree - have used Fernox many times successfully.

PTFE tape is probably the easiest solution to try first, if a bit more tightening of the nut does not cure it.

 

[Lime]

Most of the problem has been covered by other posters.
Just to emphasise, there are two seals that can leak, the one connecting the pipe (which will only leak when it is flushed) and the seal between the system and the flush mechanism.
As has been said, don't over-tighten these threaded connections as the plastic can split.
The hole through the cistern bottom is often very big in relation to the flush mechanism thread so may need something more substantial than ptfe tape.
I have never known a high modulus silicone sealant to leak or fail as long as all parts are dry to start with before application and all gaps are filled.

 

[middi]

As the cistern outlet pipe is not under any serious water pressure the best and old trusted way to stop these leaks was the trusted method of generousely smear both sides of the cistern hole with linseed oil putty, do not overtighten joints, the putty will compensate for every nook and cranny ( including encrusted calcium deposits). The putty retains it's sealing qualities and will not go rock hard.

The plumbers of old go away with it fo decades.

 

[Nigel Watts]

Great advice - thanks alot!

 

[Lime]

As the cistern outlet pipe is not under any serious water pressure the best and old trusted way to stop these leaks was the trusted method of generousely smear both sides of the cistern hole with linseed oil putty, do not overtighten joints, the putty will compensate for every nook and cranny ( including encrusted calcium deposits). The putty retains it's sealing qualities and will not go rock hard.
The plumbers of old go away with it fo decades.

That was the normal method of sealing pipework years ago in the days of ceramic or metal syphons and cisterns not plastic.
My experience has been that linseed oil putty solidified over time making separation difficult.

The use of linseed oil putty on any plastic is not recommended as the oil will cause damage.
It leaches into plastic and causes it to fail and split.

 

[ian]

The modern version of linseed putty is a thing called Boss White - a non setting paste. Most of the sheds should carry it in small tubs (500gms?). It does not harden fully and, i believe, is compatable with plastics.

 

[Penners]

Do as Feltwell (and others) suggest. LS-X. It's brilliant stuff.

 

[Nigel Watts]

At the weekend I bought some PTFE tape from my local hardware supplier (they didnt have Fernox LS-X, pumbing not being their speciality). This tape is strange stuff. It seems to have no adhesive properties whatever, and I found it quite impossible to get any to stay on the inside thread although I did manage to get some to stay in place on the external thread and round the rubber seal. The leak has certainly reduced as a consequence but has not been eliminated.

Was I sold a duff roll?

I am going to try to get a tube of the Fernox from a specilaist plumbing supplier next.

 

[MdB]

This tape is strange stuff.

Yep.

It doesn't have any stick and yes you have to put it on the male thread. There is no hope of putting it on the female thread. Don't put it on too close to the end of the thread as there is a danger that some pieces of the PTFE can be sliced off and get up to no good in your system. As the thread is done up, the tape compresses dramatically so you need to put a lot on. Try with 10 turns. It will look like there will be no way you will be able to do the thread up but it will.

 

[Lime]

I warn you that tightening plastic nuts too tight.. and if they need tightening because they are still leaking then that is too tight ... the thread will strip or over-run easily.
Then you will need a new flush mechanism.
Plastics are not like metal fittings they must not be tightened much beyond normal hand-tight.

Almost cetainly, using ptfe, it will eventually leak around the cistern lower opening and the threaded pipe of the flush mechanism.
Ptfe only compresses it does not spread like other more-fluid sealants.

 

[Pford75]

I would use Plumbers Mait (a non-setting plumbers putty). If the pipework is hidden away, then it's possible to completely cover the joint in this since you won't mind what it looks like.

 

[Pford75]

Quite a good thread at Screwfix here on a similar topic

http://www.screwfix.com/talk/thread.jspa?threadID=18046&start=15&tstart=0

 

[Penners]

Try with 10 turns. It will look like there will be no way you will be able to do the thread up but it will.

And do remember to wind it around the male thread in the same direction as you would turn a nut to screw it on to that thread. If you wind it in the 'unscrew' direction it will just ruck up and may not work properly.

 

[Jon Maine]

Ah the good old plastic tape for everything, I remember it well....... :wink:

 

[FamilyWiggs]

Sounds like you may be getting into new flush territory. A very simple job, costs about 16 quid in B&Q and about 15 minutes total to fit (including finding the stop cock and turning off the water!).

New flushes can be very nice, quiet fill ones.