Axor Independent Shower Unit

[ChrisR]

There's a pipe open to atmos[here on the HW side - danger is that it sucks air when pumped.
SOmetimes you vcan alter the pipes a bit to get away with this: (note the pipe from the cylinder goes up at 45 degrees which yours won't at the mo)

But it's safer to use a "Flange" on the cylinder, such as a Warix or Essex. (look em up!)

That shows a double ended pump. Two singles would be v similar.

 

[pdfctu]

thanks for pic..... makes sense now .. think best to try to change for a low pressure