OK I am confused and hope someone can help. I have now disabled the limit switch as an estop and have it as a homing sw only. All other axis work as they should. The Z axis runs to the Pos home switch, triggers the switch and then stops. It will not retract off of the switch. Any reason for this??
I am under the impression there is no settings in Mach for retracting, it just moves until the switch opens again then stops??

homing sequence depends in most cases from Motion Controller you are using.
Mach3 with PP will only move until Limit Switch is cleared, without retract.