This paper applies control analysis techniques to study the response of two moving-boundary nodal models for the prediction of the time evolution of the boiling boundary in a heated channel. A model based on finite elements shows anti-resonances in the gain versus frequency curve similar to that of exact solution. The gain of the second model, based on a finite difference approach, has a damped variation with the frequency. This is the same with that of the conventional linearized fixed control volume model. The number of nodes to be used in a subcooled region is given for the models vs, frequency range of flow oscillation.