Commissioning problem.

Hi, I've had a good search but can't find my issue mentioned anywhere.

I have almost finished building my first 3D printer based on a Rostock Delta.
I have installed the Marlin modified firmware and manually I can drive up and down and home with no problems.

However, when I select print it warms up the printhead, homes the 3 carriages at the top, and then tries to go upwards.???
I have tried this in Pronterface, Cura and Repetier and they all do the same.
It must be a config setting but I cannot find it.

Does anyone have any idea what's wrong or a working firmware they could post.

Many thanks

George



Sanguinololu electronics.
Nema17 steppers.
mxl pully's and belts.
Smooth rods with linear bearings.
Jhead clone hotend.
Top endstops