The compressor delivers hot compressed refrigerant to the condenser. Flow from the condenser to the evaporator is regulated by a thermostatic expansion valve having its sensing points (pressure and temperature) located in the compresser suction line downstream of an evaporator outlet control valve which is the new part in this application. This control valve has a piston type valve which is operated by a pilot valve actuated by the bellows in the suction line. The bellows is part of a charged system incorporating the capillary tube and the feeler bulb positioned in the evaporator fins. The charging fluid is selected to have a different thermal coefficient of expansion than the bulb so that the pilot valve will close at a selected temperature indicative of incipient icing conditions in the evaporator as may be found in air conditioning systems in which the compressor capacity can exceed the evaporator capacity (typical in automotive air conditioning). When the pilot valve closes pressure on the piston valve balances and the spring closes, the piston valve leaving a bleed port open to insure proper lubrication and cooling of the compressor.