Shower water to supply toilet

[sicetaitsimple]

As you will see....I am not a designer....but hope that this will be enough to understand.

In my opinion, this cannot work properly as you plan. As soon as the "steel" tank is full, the water level will rise in the pipes in 40 and I do not think that a pipe with a diameter of 20 (and 20m long) can evacuate the flow of a shower with very little water height. In short, it's not just going to be a shower, but also a foot bath, it's not going to drain!

[olivierdu33]

yes you are right I did not indicate:
at the exit of the drain of the floor D40 I am thinking of putting a T for either recycling or everything to the sewer, if the tank is full, the pipe is full and therefore the gray water goes directly to the sewer.

Plus it's a walk-in shower...so it will quickly make a shower floor!

[sicetaitsimple]

Well, without any guarantee, it's up to you, I'm not responsible for anything!
Since your 20 pipe is buried over its entire length (no rise), it would seem preferable to use it to connect the two tanks, with a connection at the bottom of each of the two.
Except when there is a shower in progress, the level in the two tanks would balance by gravity.
Of course, this means much less storage capacity in the outer tank, unless the inner tank is raised.
Now, a 20 diameter pipe conveying (and storing) gray water, how it can behave over time, no idea. But that doesn't change anything or not much from this point of view compared to your diagram.

[Christophe]

Um...where is the lift pump?

Because it will never go up into the upstairs toilet on its own...well it does...when the 2 tanks are full (and only if the shower drain is higher than the top of the bowl... )

Frankly, in your place I would forget the upstairs toilet (even if it means using it less)...because that will make things completely more complex (savings on the pump...and its consumption/maintenance!).

Even if it means having an outdoor tank, why not supply it with rainwater to supply the downstairs toilet (only)?

[olivierdu33]

@sicetaitsimple
using the tanks in series and having the two tanks gravity balanced seems to me a very good idea, I can raise the inner tank, but I am not going to drill the stainless steel to add an outlet... (easily doable to install an outlet without welding ???)

@Christophe
I haven't drawn the pump or the pressure switch because I don't really know where to place them.
(the pressure switch at the feeder inlet I think)

The external tank can be a rainwater reserve which I would like to believe simplifies things, even if I haven't thought about the device, but with 220 L of rainwater I won't last long.... autonomy.

what do you think about mixing the solutions...
if I can make a tap at the bottom of the stainless steel tank, it fills with gray water and the one outside with rainwater and if empty with gray water by gravity, the pump supplies the toilets....

[Ahmed]

To create a lower outlet from the stainless steel tank, it is possible, after having made the appropriate hole with a hole saw, to use a connector which is inserted from the inside and has a threaded part allowing everything to be tightened on the internal joint: the pipe then attaches to the end of this connection.

[sicetaitsimple]

using the tanks in series and having the two tanks gravity balanced seems to me a very good idea, I can raise the inner tank, but I am not going to drill the stainless steel to add an outlet...

in your first post, you told us that your stainless steel tank had a "1/2" inlet and outlet.
I assume it's 1/2 inch?
This is, from my point of view, totally insufficient for a gravity system. You'll have to modify it if you want to use it.

[Christophe]

Yes simple and I'm not even sure that all the flush "taps" work at low pressure (< 0.5 bar)... to test... before anything else...

[izentrop]

@Christophe
I haven't drawn the pump or the pressure switch because I don't really know where to place them.
(the pressure switch at the feeder inlet I think)

Logically, its place is at the outlet of the stainless steel tank and the pressure switch with NC contact, just at the outlet of the pump, so the pump is activated as soon as a WC tank empties and stops when it is full.
No guarantee that this small pump will be able to pump water up to the upstairs toilet (no indication in the characteristics), however it will stop if there is no more water in the stainless steel tank (incorporated pressure switch).

[sicetaitsimple]

No guarantee that this small pump will be able to bring water up to the upstairs toilet (no indication in the characteristics).

Yes, 130PSI or approximately 9 bar. If it works correctly, that should be enough! It will certainly even be necessary to add a regulator.