Theoretical analysis of the steady state performance of a load sensing hydraulic flow control valve, having priority to primary circuit and an excess flow secondary outlet, is presented in this paper. Basic control system feature of such a valve with fixed displacement pump is considered. A constant flow with a priority to a primary circuit occurs irrespective of the amount of load pressure, whenever a demand is created by opening a control orifice. Analysis is carried out for variable area control orifice to find out the optimal operating conditions and parametric values. The effect of flow forces on the spool equilibrium is also investigated. In some critical situations flows through both the ports occur which are also studied. Some results are verified experimentally. Analysis helps also as a design guideline.