Bizarre double-tap fixture in kitchen, with one tap that doesn't seem to do anything?

[semw]

This is in Germany, if it makes any difference.

Picture:

Task: plumb in a new washing machine.

So: pipe comes out of the wall, goes straight into this fixture with two taps. Goes up to sink and (through another tap, left) dishwasher. Goes down to washing machine.

The higher, smaller tap controls water to the sink & dishwasher, and works fine.

The lower, bigger tap.. doesn't seem to do anything at all.

At first I thought the lower tap was a master tap for everything, but (unlike the upper tap) it had no effect on sink water. So then I assumed it must control just the bottom outlet (to the washing machine). So I turned it off, and tried to slowly disconnect the washing machine valve from the pipe. Water sprayed out at pressure. Huh. I thought there might be water left in the valve thingy, but after soaking through a couple towels without the pressure letting up, that clearly isn't the case.

(I also tried turning it all the way anticlockwise in case the tap somehow worked the wrong way round, but nope)

So, what's going on here? Am I doing something wrong, or is the lower tap just broken? (There's no central water shutoff to just my flat that doesn't also shut off water to several other flats, so I can't just do that to install the washing machine).

Thanks in advance

 

[breplum]

Hi. It is great for us to see Euro plumbing. Certainly bizarre to any of us.
That valve shown is not available in the U.S. so none of us are going to be able to help you.
In the U.S. it is required that each fixture have its own valve to regulate a single fixture.
If I were to guess, my vote would be that the valve with the blue dot should shut everything off.