I'm running a thermal simulation using 1/2 symmetry and getting some odd results across the symmetry face.  As I recall the proper way to imply symmetry for themal is to apply no boundary condition at all on the symmetry face and thus no heat flux will occur across the boundary.  The problem has thermal contact as well.  Anyways I see temperateratures on the symmetry face of -273C while the one part is held at 600C and the ambient air is at 800C so this is impossible.  Any ideas as to why this is happening?