New Cistern hooking up to green DIY toilet top sink

[daytonavrs]

Any advice on the following

Round tuit job of fitting a wash basin in outside conservatory - I have now replaced a plastic cistern with a china one (now far better secured than the plastic one that was falling off) so have got hands wet with plumbing as I don't usually.

Did try to have job done by a plumber twice but no keenness and ended up doing the low level toilet cistern myself Credit though its working fine.

Put off by normal sink fitting as I read only difficulties with tapping into. Plumber came round was like "tap waste into loo" but from what I read on more recent planning was alarm bells and I'm reading that building regs are required ?

Now want to complete a simple green washbasin idea to hook up a copper dish I have to the clean water inlet of the new cistern so all doing is just reusing water that will be flushing. To be mounted dish on an existing shelf I'm refitting above the cistern.

It has a 25mm side fitting for overflow not fitted to go outside and wasn't on old one by whoever did it - I guess a conservatory toilet area like this is practically outside anyway lol, and was thinking of using flexi pipe or something from an unslotted waste?

Its a new cistern I wasn't thinking of chopping that up or replacing with wood covers as I've seen some done but thinking to take the 32mm waste from sink ( doesn't need trap?) and to tap it into that right overlow but would need to reduce 32 to 25 ?
On the downside the pipework might then be preferable to be hidden by something but I'm less fazed by seeing a bit of pipe if necessary.

[Paul Drawmer]

If the cistern is full when you wash your hands, what will happen to the hand wash water?
Or will you rely on hand wash water being enough and not have an automatic mains refill?

[daytonavrs]

Hi Paul,
The idea is that its for when you just want a pee mostly and so can lubricate your hands a bit with the slow water intake for the cistern

The feedback loop for the cistern itself is not affected - just diverted via the cistern intake to the bowl, then back to the cistern so as it fills you wash your hands with that clean water going back into the cistern?

You have the unslotted basin ( copper vessel ) sans overflow or plug so its waste just fills the cistern itself as it would normally just a longer path.

I understand siphons have their own overflow once the water level is above the point of the siphon itself so in this case was thinking to use that cavity?

If this is a bad idea I can still take the 25mm outside for backup overflow then and try to carefully drill a larger cavity into the cistern lid or high side for the waste/ cistern fill from the long way around

[Paul Drawmer]

Ah, so each time you flush, the refill water will just come out of the basin spout and then drain into the normal cistern fill?

[daytonavrs]

Yes. That does mean you have a time limited to wash your hands with limited water, but a reasonable compromise I feel for a simple 2nd toilet option.

There has been this toilet in conservatory without sink for some time so just a quick and easy way to do it, seems many have done this path and it also saves on water but does mean you can't just wash your hands normally but that's ok.

There is a sink adjacent if you walk thru house to the kitchen but just makes sense to have some kind of running water if you having a toilet, why not the toilet top type.

Already got a nice copper dish just planning to bend some copper pipe around to form the spout around it? Fairly simple, just need the basic plumbling bits and as mentioned was hoping I could use the currently open right hand cistern hole for overflow instead as flow back into cistern and just rely on the overflow built into the siphon ( unless that's a bad idea ).

[Paul Drawmer]

How are you going to switch the water on and off? when the float in the cistern drops and opens the inlet valve to the cistern, how will you be modifying the inlet system to divert the water up to your basin spout?

I think I've missed something here!

[dhutch]

Paul Drawmer said:

....so each time you flush, the refill water will just come out of the basin spout and then drain into the normal cistern fill?

Yeah, I guess why not?

Paul Drawmer said:

....how will you be modifying the inlet system to divert the water up to your basin spout?...!

Struggling to find a really neat of the shelf method, but I am sure it can be done!

[daytonavrs]

Paul Drawmer said:

How are you going to switch the water on and off? when the float in the cistern drops and opens the inlet valve to the cistern, how will you be modifying the inlet system to divert the water up to your basin spout?

I think I've missed something here!

Just mating some similar sized piping into hole that usually goes into the downward feed tube?

One guy that did it found it was push fit, not sure I will be lucky enough and might have to use some solvent.
Almost all that do this seem to fit a top sink opt for copper piping bent to shape, though some have tapped in taps.

Its like you have on a torbeck fill valve that have a push on plastic pipe that diverts water down, instead you push in copper pipe so it goes outside the cistern and above the copper vessel/ sink.

Paul Drawmer said:

....so each time you flush, the refill water will just come out of the basin spout and then drain into the normal cistern fill?

Bang on, a time limited hand wash but ok for a "spare" toilet introducing a sink we never had before

[daytonavrs]

Probably opt for smaller pipe that pushes inside and small diameter, of course the water pressure may not be very high but should be ok for a "P" wash better than nothing (current)

[g7jtk]

This sounds like what you need.
https://www.heatandplumb.com/acatalog/delphi-p2-to...

Messing with the fill valve outlet sounds like a contravention of water regs. Unless it’s a tank supply.

[dhutch]

g7jtk said:

This sounds like what you need.
https://www.heatandplumb.com/acatalog/delphi-p2-to...

Presumably the plumbing for the sink in that application is completely separate from the cistern. No water saving scope, but hot water provision.

[Mabbs9]

Your idea sounds quite similar to what I see in Japan and Korea I think? It struck me as a pretty good idea.

[daytonavrs]

g7jtk said:

This sounds like what you need.
https://www.heatandplumb.com/acatalog/delphi-p2-to...

Messing with the fill valve outlet sounds like a contravention of water regs. Unless it’s a tank supply.

I've only just fitted a new cistern so I'm unlikely to go for a complete new toilet to achieve the very same idea!

Those fill valves have a "down facing" pop on diverter that if it came off would also end up with leaking water everywhere so I don't really see the difference tbh.

[g7jtk]

dhutch said:

Presumably the plumbing for the sink in that application is completely separate from the cistern. No water saving scope, but hot water provision.

No. The waste water drains into the cistern then overflows into the pan. You also get to have hot water.

[smithyithy]

As the poster above's image - they're quite common in Japan / Asia especially in tiny apartments. I used one in Japan and it worked perfectly well.

I've just completed on my first house and it has a tiny downstairs loo between the kitchen and rear garden. There's barely enough room for your legs in front of the basin let alone anywhere for a sink, so I'm quite tempted to go with the above option in order to add a sink in there...

[daytonavrs]

smithyithy said:

As the poster above's image - they're quite common in Japan / Asia especially in tiny apartments. I used one in Japan and it worked perfectly well.

I've just completed on my first house and it has a tiny downstairs loo between the kitchen and rear garden. There's barely enough room for your legs in front of the basin let alone anywhere for a sink, so I'm quite tempted to go with the above option in order to add a sink in there...

Good luck with it hope the installation goes smoothly for you and sounds like a cracking idea for those circumstances.