Z not moving down

[Oxndv]

My Z axis cannot go down with manual control (in Rapetier-Host GEEEtech), even when Z axis is manualy set up +xx mm. I can move Z axis down only after when i do Auto Home. But i can never go lower (with using software manual control) as it's set.

Every time i hit Auto Home for Z axis, it just move up about 4mm.

Does it mean that i must before every printing set manualy Z axis 0.1mm from platform?

Edit:
I found out that at start of printing Z axis move up around 2mm and then start printing. A few layer of printed model looks quite messy. At start of printing i manualy calibrate nozzle 0.1mm from platform, because in software i cannot auto home Z axis (it just do same like before printing +~2mm).

[William]

Hi,
Did you fix it?And what model is your printer?

[Oxndv]

Hello

Model of my printer is prusa i3 pro B. I fixed everything, it took me some time but i figure out that i had connected Z axis end stop into Y axis end stop(MAX). So it somehow know if there is no connected end stop in board (for Z axis), and if called for auto home it just move up ~4 mm that it could not cause any damage. And Z axis auto moving up for few mm before printing, was caused by added line into start G-code by slic3r (something like this: G1 Z2).

[William]

Hi！
Is your printer working properly now？

[Oxndv]

Yea, works like charm.