A toilet cistern that doesn't leak
Matty F
pressed. I have installed one that does that already, but every now
and then some moron manages to flush in such a way that the valve at
the bottom of the cistern leaks slightly, or lifts the lid or the
cistern half off the wall.
The result is that the rainwater tank empties its 30 cubic metres of
water into the toilet, and there's no water for anything until the
cistern is fixed and it rains.
I suppose some kind of syphon cistern would work except that it would
do a full flush every time. Or if there was a part-flush mechanism the
morons would manage to wreck it.
Elsewhere I have a very old syphon cistern that people manage to flush
with some weird action so the water runs continuously.
An idea has just occurred to me - to put a very heavy weight on the
valve of the existing cistern.
Dave Liquorice
--
Cheers
Dave.
Dave Liquorice
> Ideally I'd like a cistern that flushes only as long as the button is
> pressed.
That might be hard to arrange with your limited water supply. B-)
I have installed one that does that already, but every now
> and then some moron manages to flush in such a way that the valve at
> the bottom of the cistern leaks slightly, or lifts the lid or the
> cistern half off the wall.
Remove cistern. Provide a tap, that you have to hold on to get water, and
bucket.
is the rain water supply well filtered before it gets to the cistern? Is
crud getting under the flap valve?
> I suppose some kind of syphon cistern would work except that it would
> do a full flush every time. Or if there was a part-flush mechanism the
> morons would manage to wreck it.
> Elsewhere I have a very old syphon cistern that people manage to flush
> with some weird action so the water runs continuously.
Syphons, IMHO, tend to be much more reliable. One of ours will
occasionally end up in that non-stop running state not quite sure how it
manages it but it is related to trying to flush when the cistern is not
completly refilled. Just a small amount of flush will stop it ie just
enough to splash some extra water round the bowl not a full flush. I
wonder if a small hole in the top of the syphon will cure it? I mean
small, as in tiny, as in pinhole, just enough to slowly leak a bit of air
in to break any partial syphon that is set up but not enough to upset the
main flush syphon.
> An idea has just occurred to me - to put a very heavy weight on the
> valve of the existing cistern.
Might be worth checking how much play there is in the bearing of the flap
and that it can't easyly catch on the sides as it drops back.
--
Cheers
Dave.
Thomas Prufer
wrote:
>Ideally I'd like a cistern that flushes only as long as the button is
>pressed. I have installed one that does that already, but every now
>and then some moron manages to flush in such a way that the valve at
>the bottom of the cistern leaks slightly, or lifts the lid or the
>cistern half off the wall.
If "leaks slightly" is less than 0.5 l/min, this here might help:
http://www.wayscale.com/aqua-block.shtml
They also sell more complex systems, but I'd suspect that the price would be too
high for the benefit...
Thomas Prufer
Matty F
wrote:
> On Fri, 29 May 2009 02:40:55 -0700 (PDT), Matty F wrote:
> > Ideally I'd like a cistern that flushes only as long as the button is
> > pressed.
>
> That might be hard to arrange with your limited water supply. B-)
I don't understand that. There is usually 30,000 litres available
until the moron arrives..
> I have installed one that does that already, but every now
>
> > and then some moron manages to flush in such a way that the valve at
> > the bottom of the cistern leaks slightly, or lifts the lid or the
> > cistern half off the wall.
>
> Remove cistern. Provide a tap, that you have to hold on to get water, and
> bucket.
We had two taps like that, very expensive. They were stolen for the
brass content.
> is the rain water supply well filtered before it gets to the cistern? Is
> crud getting under the flap valve?
That's a possibility. Any reasonable person would notice that the
water continues to flow, and would do something to stop it.
> Syphons, IMHO, tend to be much more reliable. One of ours will
> occasionally end up in that non-stop running state not quite sure how it
> manages it but it is related to trying to flush when the cistern is not
> completly refilled. Just a small amount of flush will stop it ie just
> enough to splash some extra water round the bowl not a full flush. I
> wonder if a small hole in the top of the syphon will cure it? I mean
> small, as in tiny, as in pinhole, just enough to slowly leak a bit of air
> in to break any partial syphon that is set up but not enough to upset the
> main flush syphon.
My syphon has such a hole. The size is critical. I've tried to find
someone who knows how a syphon cistern *really* is supposed to work,
but nobody seems to know. A moron can defeat a syphon cistern and make
it run continuously.
> > An idea has just occurred to me - to put a very heavy weight on the
> > valve of the existing cistern.
>
> Might be worth checking how much play there is in the bearing of the flap
> and that it can't easyly catch on the sides as it drops back.
There's a pipe that slides up and down in a tube, all plastic, with a
flat rubber washer at the bottom. I can't see how it can go wrong. But
faced with morons who take the lid off the cistern or pull the cistern
half off the wall, anything is possible.
Matty F
online.de.invalid> wrote:
> On Fri, 29 May 2009 02:40:55 -0700 (PDT), Matty F <mattyf9...@yahoo.co.nz>
> wrote:
>
> >Ideally I'd like a cistern that flushes only as long as the button is
> >pressed. I have installed one that does that already, but every now
> >and then some moron manages to flush in such a way that the valve at
> >the bottom of the cistern leaks slightly, or lifts the lid or the
> >cistern half off the wall.
>
> If "leaks slightly" is less than 0.5 l/min, this here might help:
>
> http://www.wayscale.com/aqua-block.shtml
>
That's a possibility. But the water pressure is very low, that's why
I have a cistern that fills up.
Two other possibilities are:
1. take the water from near the top of the water tank. If they stuff
up the cistern at least it won't drain the whole tank.
2. an electric valve to shut off the water if the power is turned off.
But the morons will leave the power on.
They are already supposed to turn the tap from the main tank off. But
they don't. Perhaps there should be a penalty of $100 for not turning
the water off, paid in advance.
Thomas Prufer
wrote:
>1. take the water from near the top of the water tank. If they stuff
>up the cistern at least it won't drain the whole tank.
Could you use a second, small cistern as a feed, filled manually by opening a
huge valve connected to the first? I.e. a r
>2. an electric valve to shut off the water if the power is turned off.
>But the morons will leave the power on.
Look at the other clever things at the wayscale site -- here's a PIR that turns
on the water when there's motion, and shuts it off with a delay when there
isn't:
http://www.wayscale.com/aquapir.shtml
>They are already supposed to turn the tap from the main tank off. But
>they don't. Perhaps there should be a penalty of $100 for not turning
>the water off, paid in advance.
That might work where signs and appeals to common sense fail.
Thomas Prufer
dennis@home
"Matty F" <matty...@yahoo.co.nz> wrote in message
news:62837a78-3c9a-4486...@s28g2000vbp.googlegroups.com...
>> Syphons, IMHO, tend to be much more reliable. One of ours will
>> occasionally end up in that non-stop running state not quite sure how it
>> manages it but it is related to trying to flush when the cistern is not
>> completly refilled. Just a small amount of flush will stop it ie just
>> enough to splash some extra water round the bowl not a full flush. I
>> wonder if a small hole in the top of the syphon will cure it? I mean
>> small, as in tiny, as in pinhole, just enough to slowly leak a bit of air
>> in to break any partial syphon that is set up but not enough to upset the
>> main flush syphon.
>
> My syphon has such a hole. The size is critical. I've tried to find
> someone who knows how a syphon cistern *really* is supposed to work,
> but nobody seems to know. A moron can defeat a syphon cistern and make
> it run continuously.
>
The only way a siphon can run continuously is if you are filling the cistern
as fast as the siphon can empty it.
You need to restrict the flow so the water reaches the bottom of the cistern
and the flow stops.
The hole in the pipe is usually for "dual flush".
It is covered when the handle is held down and will give a flush that lasts
until the cistern is empty, but is uncovered when the handle is released
breaking the flow.
If people tamper too much, fit a concealed one behind the wall.
Dave Liquorice
>>> Ideally I'd like a cistern that flushes only as long as the button is
>>> pressed.
>>
>> That might be hard to arrange with your limited water supply. B-)
>
> I don't understand that. There is usually 30,000 litres available
> until the moron arrives..
Ha! .nz not following a literal reading of the english and british sense
of humour. B-) You don't say how long the button will be pressed for. It
could be jammed pressed and with only 30,000l available it will run out so
you can't have a flush that lasts "as long as the button is pressed".
>> is the rain water supply well filtered before it gets to the cistern?
>> Is crud getting under the flap valve?
>
> That's a possibility. Any reasonable person would notice that the
> water continues to flow, and would do something to stop it.
Personally I push the flush and walk away to wash hands. I don't watch to
see if the flush completely stops.
> There's a pipe that slides up and down in a tube, all plastic, with a
> flat rubber washer at the bottom. I can't see how it can go wrong.
You seem to describe two different flush valves. My troll alarm is
starting to sound. What you describe above is a normal syphonic flush
mechanisium.
http://www.practicaldiy.com/plumbing/cistern_syphon/cisterns_syphon.php
Is good but isn't 100% accurate:
"The syphon continues to work until air is drawn into the cistern."
Should read "syphon" at the end. If air can't get into the cistern the
water can't get out, full stop...
And they use the term "flap valve" when refering to the disc that lifts
the water. Don't confuse this with a "flap valve" type of flush
mechanisium where there is conical "flap" and coresponding shaped hole in
the base of the cistern over the entrance to the down pipe. With this type
a flush is created by simply lifting the valve open.
--
Cheers
Dave.
Dave Liquorice
> The only way a siphon can run continuously is if you are filling the
> cistern as fast as the siphon can empty it. You need to restrict the
> flow so the water reaches the bottom of the cistern and the flow stops.
Not strictly true. There is some way that our syphonic flush cistern can
end up running continuously. It's not at full flush rate but still a
noticeable flow down the back of the bowl and no it's not an internal
overflow...
I can't get my head around how it does it, but it does.
> If people tamper too much, fit a concealed one behind the wall.
Reading the OP's follow up that is probably the only real solution, deny
access to the workings. Boxing in with 12mm ply on a sturdy well fixed
frame should do it.
--
Cheers
Dave.
Matty F
wrote:
> "Matty F" <mattyf9...@yahoo.co.nz> wrote in message
> > A moron can defeat a syphon cistern and make it run continuously.
>
> The only way a siphon can run continuously is if you are filling the cistern
> as fast as the siphon can empty it.
The moron jiggles the chain up and down several times in a random way
thus triggering the continuous flush. The situation then appears to be
that the cistern has half refilled with water, covering the small air
vent hole half way up the bell. The pipe going from the cistern to the
toilet bowl is full of water which is emptying into the toilet and
sucking water out of the cistern.
> You need to restrict the flow so the water reaches the bottom of the cistern
> and the flow stops.
The flush proceeds normally until the moron pulls the chain again.
> The hole in the pipe is usually for "dual flush".
> It is covered when the handle is held down and will give a flush that lasts
> until the cistern is empty, but is uncovered when the handle is released
> breaking the flow.
In this case the cistern is around 130 years old and has no dual flush
facility.
The hole is half way down the syphon bell. It's there to allow air to
enter so that the pipe to the toilet may empty of water and stop the
flush.
> If people tamper too much, fit a concealed one behind the wall.
The cistern that is the subject of this thread is concealed behind a
wall. But people can walk around the back of the building to see it.
Which gives me an idea - I'll put a big box around it and padlock it
closed.
And put a big weight on the valve so that it closes properly.
Failing that I'll remove everything and they can have a pit toilet
again complete with 12 inch cave wetas.
These are what are lurking under the seat:
http://i33.tinypic.com/2a9xgjt.jpg
PeterC
> here's a PIR that turns
> on the water when there's motion, and shuts it off with a delay when there
> isn't:
Come on - let's have the jokes!
--
Peter.
You don't understand Newton's Third Law of Motion?
It's not rocket science, you know.
PeterC
>> I have installed one that does that already, but every now
>>
>>> and then some moron manages to flush in such a way that the valve at
>>> the bottom of the cistern leaks slightly, or lifts the lid or the
>>> cistern half off the wall.
I had that problem - slackening the push-button a quarter-turn stopped it.
It was just occasionally jamming slightly.
If the button does jam down that's not the fault of the operator - there's
nothing that one can do wrong with a button except hold it down for too
long.
Matty F
wrote:
> On Fri, 29 May 2009 16:13:51 -0700 (PDT), Matty F wrote:
> > There's a pipe that slides up and down in a tube, all plastic, with a
> > flat rubber washer at the bottom. I can't see how it can go wrong.
This cistern (the one with the leaking problem) is *not* a syphon
cistern. The flat rubber washer covering the pipe to the toilet is
just pulled up for a flush. The one at my house *is* a syphon cistern
but is very old (in a heritage building so I don't want to change
anything).
> You seem to describe two different flush valves. My troll alarm is
> starting to sound. What you describe above is a normal syphonic flush
> mechanisium.
>
> http://www.practicaldiy.com/plumbing/cistern_syphon/cisterns_syphon.php
Well that's certainly an improvement over the syphon cistern that I
have here at home. Perhaps I can buy one like that. Mine is all cast
iron. There are two moving parts apart from the inlet valve and float
- there's a big bell and a lever to lift it up.
Matty F
> On Fri, 29 May 2009 16:13:51 -0700 (PDT), Matty F wrote:
> >> I have installed one that does that already, but every now
>
> >>> and then some moron manages to flush in such a way that the valve at
> >>> the bottom of the cistern leaks slightly, or lifts the lid or the
> >>> cistern half off the wall.
>
> I had that problem - slackening the push-button a quarter-turn stopped it.
> It was just occasionally jamming slightly.
> If the button does jam down that's not the fault of the operator - there's
> nothing that one can do wrong with a button except hold it down for too
> long.
Since the cistern is outside the building, I have removed the push
button and replaced it with a pull cord that goes through a hole in
the wall. There's a knot in the cord to stop it being pulled too far.
I'll add a lump of lead to the valve to make sure it closes!
Dave Liquorice
> The moron jiggles the chain up and down several times in a random way
> thus triggering the continuous flush.
<snip>
> The pipe going from the cistern to the toilet bowl is full of water
> which is emptying into the toilet and sucking water out of the cistern.
Except that the pipe leading to the bowl is quite large bore. I can't see
what stops air entering that pipe from the bowl letting the water out of
pipe and thus stopping any syphon action. Maybe some form of airlock in
the down pipe?
--
Cheers
Dave.
Matty F
wrote:
The only syphon cisterns I have seen are very old ones and the
principle is different (and rather poor I think). There is a large
cast iron bell that is lifted up to raise the water. To avoid sucking
air from near the bowl there is a U-bend at the bottom end that is
full of water. Otherwise when the bell is lifted no water would be
raised.
In order to stop the syphon there is a small air hole half way up the
bell.
Dave Liquorice
> This cistern (the one with the leaking problem) is *not* a syphon
> cistern. The flat rubber washer covering the pipe to the toilet is
> just pulled up for a flush. The one at my house *is* a syphon cistern
> but is very old (in a heritage building so I don't want to change
> anything).
Ah two bogs that's the confusion...
I'm not surprised a flat rubber washer leaks you need something that will
self centre and have a large sealing area. A bit of sheet lead across the
back of the flap may help but I think you'd probably be better off trying
to find something like:
http://www.screwfix.com/prods/36240/Plumbing/Toilet-Fittings/Flapper-Toile
t-Cistern-Valve-Handle
--
Cheers
Dave.
Matty F
wrote:
> t-Cistern-Valve-Handle
Actually the rubber washer is centred quite well. Almost all cisterns
I've seen here have a similar system. However dirt could cause a leak,
and this toilet is in the middle of dense bush.
I think I have invented a solution. I really only need a few litres
for a flush, because the toilet is over a long drop and looks like
this:
http://i43.tinypic.com/288mfwm.jpg
I will have a vertical pipe in the cistern with large holes in it near
the top. Sliding on that I will have a plastic 3 litre box that may be
pulled up so that water goes down the holes. Simple and can't leak and
can't be blocked.
Dave Liquorice
> Actually the rubber washer is centred quite well. Almost all cisterns
> I've seen here have a similar system.
Common in the US, at least thats the impression I got when googling to
find a page that described how a flush cistern works.
> I think I have invented a solution.
<snip>
> I will have a vertical pipe in the cistern with large holes in it near
> the top. Sliding on that I will have a plastic 3 litre box that may be
> pulled up so that water goes down the holes. Simple and can't leak and
> can't be blocked.
Why reinvent the wheel? How do you reliably get suitable seal(*) between
the pipe and box and guide the box so it doesn't tip and jamb? How do you
get the empty box to sink and refill in a reasonable time?
Are modern flush syphons not available in .nz?
They are:
http://www.bathaus.co.nz/Products/Detail.aspx?id=13498
WOW! NZD137 - GBP54 They are about GBP12 over here!
--
Cheers
Dave.
Matty F
wrote:
1. As I've explained I want a flush of only up to about 3 litres at a
time. A syphon will empty the whole or half the cistern.
2. That price is a ripoff
3. This is a d-i-y group.
4, The pipe will thread through a hole in the top and bottom of the
box so the box will not tip. Only a tiny amount of water can go
through the small gap between the pipe and the lower hole, in the one
second while lifting the box.
Dave Starling
I had to re-read the amount of rainwater you are talking about. 30,000
litres! Thats some going considering a typical domestic installation
is about 2700 litres. Any chance of some photos of that collection
tank...
I'd also consider the PIR approach so that it only opens a valve to
fill the cistern when someone goes into the toilet. Problem solved?
Dave
Matty F
I don't have a photo of the tank but here it is on Google Satellite.
It's the big black thing:
http://i40.tinypic.com/2wd90n6.jpg
The tank is about 3.5 metres across and high and is made from timber
with steel bands around it, and has a plastic liner. It has a shingle
roof and is fed by an automatic pump from a small tank below the hut
that is filled from the roof of the hut.
There's no power to either toilet. The pipe to the lower toilet is
very thin and has a very low pressure, but it fills the cistern fine
over a few minutes. Too long to wait for the PIR approach.
Another advantage of my new solution that costs nothing is that there
can be no continuous syphon effect that can happen with syphons, and
no leaky valves!
Dave Liquorice
> 1. As I've explained I want a flush of only up to about 3 litres at a
> time. A syphon will empty the whole or half the cistern.
3l is low but I'm sure it could be achieved by adjusting the water level
and a hole below the water line in the syphon. That is how the dual-flush
syphons work, there is hole that is blocked if the handle is held but
unblocked if it is let go. Have the hole so it is never blocked and that
will limit the amount of water that can syphon.
> 2. That price is a ripoff
Glad to hear it!
> 3. This is a d-i-y group.
True but not many of us re-invent the wheel. B-)
> 4, The pipe will thread through a hole in the top and bottom of the
> box so the box will not tip. Only a tiny amount of water can go
> through the small gap between the pipe and the lower hole, in the one
> second while lifting the box.
How do you make you empty box sink and fill at a reasonable rate? It needs
a hole (and valve?) so that you can lift enough water fast enough. How
"moron" proof will it be? Need to stop the top of the box lifting off the
top of the pipe. Can you get enough flow rate to flush the bog, though
IIRC this is a long drop rather than a water closet type pan so only needs
a rinse down? How much pull will you need on the lifting mechansium to
lift your 3l of water, something over 6lbs. That's quite a bit how will
the morons react? More brute force?
--
Cheers
Dave.
Matty F
wrote:
> How do you make you empty box sink and fill at a reasonable rate? It needs
> a hole (and valve?) so that you can lift enough water fast enough.
I'll think of something! Probably a flap in the bottom of the box.
> How "moron" proof will it be? Need to stop the top of the box lifting
> off the top of the pipe.
I already have a knot in the cord that goes through the wall!
> Can you get enough flow rate to flush the bog, though
> IIRC this is a long drop rather than a water closet type pan so only needs
> a rinse down?
Yes it only needs a rinse down. My original design just had a tap that
flushed using the main water pipe. That was a bit slow to wash the
toilet paper off. The present cistern has almost too much flow. I
don't want too much water to go in the pit, to satisfy the critics who
don't want it flooded. However 30 cubic metres of water put in it seem
to have disappeared without trace.
> How much pull will you need on the lifting mechansium to
> lift your 3l of water, something over 6lbs. That's quite a bit how will
> the morons react? More brute force?
The box has to lift only a few inches. I can have a lever inside the
toilet to amplify the force. In fact I think I'll have a foot pedal.
That will be more hygienic.