A model predicting the behavior of a PWR condenser in case of loss of cooling flow is presented. This model enables the prediction of steady state phase (for initializing the transient scenario) and the pressure evolution modelling during the stop cooling flow and restart flow phases. The resolution is based on the discretization of energy equations of fluid inside tube and tube walls and on the use of empirical correlations to consider forced convection of inside fluid and condensation on tube walls. The impact of transient phenomena such as inertia or compression of steam is studied too. In order to do so, an experimental apparatus is set up and experimental pressure inside the condenser is compared with pressure predicted numerically. The results of the simulations agreed well with the experimental data.