A brief description of the operation and analysis of a solar water pump is given. It is shown that one of the parameters affecting the performance of the pump is the time taken for condensation of the working fluid in each cycle. The condensation time in each cycle is determined through heat transfer analysis of the condenser. The effects of inlet water temperature and mass flow rate of the cooling water to the condenser on the condensation time and the pump performance have been studied and discussed. © 1995.