What Firmware is on the pump?

Few minutes is too much logically.

1. Try to set up the jumper in the ext. temp connector pins THEN start the aquastream with the jumper on these pins....on this way you reset the firmware....
To activete deaeration mod you do it like you said, BUT WHILE the aquastream is running.

when the problem still exists, try to flash a new firmware, 1.17 is the newest.
Do you have an aquaero? When not, do it like it's explained here: http://forum.aqua-computer.de/index.php?…&threadID=92683
with the selfmade flasher