I guess your bots don't think it's worth the mana to heal a wizard. I can say I don't blame them. If you were a mage, they wouldn't have to heal you... I have heard of this wiz spell called concussion or something like that. Maybe you should check it out.
What heal spells do they have? What level? I've not had a problem being healed whether I'm a SK, monk, or warrior. As I said, sometimes they don't want to heal me out of combat, but that's rare. Either way, this should help.