This study is part of a project aimed at investigating the reasons for the noise generation and sound propagation in the hermetically sealed H25A air conditioner compressor manufactured by Bristol Compressor Co. This study aims to investigate the pressure fluctuations inside the compressor cavity and their effect on the forces generated by the impact of valves on valve seats and valve stops. In order to achieve this objective a computer program, which mathematically simulates the operation of the compressor, was written. The simulation program is capable of predicting the pressure fluctuations inside the cylinders as well as the various Cavities inside the compressor. The pressure driven forces on the suction and discharge valves can then be computed and their effect on the forces transmitted to the compressor shell be studied. The results from an earlier experimental study were used in order to verify the results generated by the simulation program. The results from the simulation program were comparable to the experimental values. / Master of Science