I don't have the pump with me (it's at school with Jess) so I can't see exactly where in the menu to set it but if I recall correctly it's in the Setup menu. If you scroll through you'll find something that says Occlusion sensitivity, have that set to high. It should alarm when there's a blockage. But we have experienced a high reading in the past when the alarm didn't sound so it's not a guarantee it will always alarm.
