Pfaff Cover Style Owner's Manual page 56

3-thread rolled hem
Program 14
The upper looper thread (pink) appears on the
underside of the fabric.
Set the pink thread tension to a higher value
and/or the yellow thread tension to a lower
value.
52
The upper needle thread (green) is too loose.
Set the green thread tension to a higher value.
The lower looper thread (yellow) appears on
the top side of the fabric.
Set the yellow thread tension to a higher value
and/or the pink thread tension to a lower
value.