A toilet cistern that doesn't leak

[Matty F]

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]

On Jun 1, 1:39=A0am, Matty F wrote: 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:

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]

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.

Glad to hear it!

True but not many of us re-invent the wheel. B-)

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?

[Matty F]

I'll think of something! Probably a flap in the bottom of the box.

I already have a knot in the cord that goes through the wall!

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.

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.