Have it your way.
We can't see inside the tap (or know what type it is), or if it's only partly open -- it is probably more constricted than the outlet.
Still there is little pressure necessary.
I put up the full table at : http://lenr.qumbu.com/rossi_ecat_sep11_drain_g.php
I was using 30 litres ... but the actual water volume was 25L (based on the time to fill the eCat), and it could be even less than that after it's been in operation.
A draining time of 7 minutes fits 1 Bar better than 2 Bar.
