Thermal simulation: constant temp + convection

Hi all,
I tried to run a thermal simulation on my model called “clean CAD”. In this model two areas have a constant temperature which I maintain it with a thermocouple and a controller connected to my heat source. The problem is that I can’t add convection inside the cylinders (where my heat source is), because I get an error saying that I have two boundary condition on the surface of my heat source.
Constant power doesn’t work for me, since it’s not constant but depends on the heat dissipation.
Any Ideas how to solve it?

Hi, and thanks for using the forum!

The link you provide seems to be wrong, could you please try to fix it so I can have a look at the setup and provide some help?