Simple heat flow model in ANSYS ( Question on FEA basics)

[nodalDOF]

I built a simple thermal model in ansys which is just a 2-d recangular area. The model runs fine and i get a nice distibution comparable to closed form solution when i specify temperatue BCs (Type I: D,all,temp,xx) at all the edges. However, i run in to HT FLOW CONVERGENCE problem when i change BC on one of the edges to ZERO heat flow (TypeII: f,all,HEAT,0). Is there something fundamental i am missing here?

Thanks,
Nodal.

 

[nodalDOF]

Figured out a small mistake in my model. It works now.