includes a casing 40 providing a housing for a diaphragm 42 and said diaphragm 42 constitutes a motor element the diaphragm 42 cooperates with the casing 40 to define an upper diaphragm compartment 44 and a lower diaphragm compartment 46 the diaphragm 42 is connected to two control rods 48 see fig6 these control rods 48 move with said diaphragm 42 and are disposed in bearing relation on the control valve spring retainer 32 referring to fig7 the upper diaphragm compartment 44 communicates with a capillary tube 50 having a thermostatic bulb 52 at a remote end which is disposed in thermal responsive contact relation with the suction line 20 adjacent the indoor coil 14 evaporator outlet a limited charge of refrigerant e g freon is introduced into the bulb 52 below a predetermined temperature at the bulb the charge is partly in liquid phase and partly in vapor phase accordingly the pressure in the upper diaphragm compartment 44 responds to changes in superheat in the suction line 20 the lower diaphragm compartment 46 communicates with an offset equalizer passage 54 formed in the upper portion of the valve body 22 which by means of an external equalizer connection 56 communicates with the indoor coil 14 evaporator downstream of the inlet of said indoor coil 14 so that said lower compartment experiences substantially the same pressure as said indoor coil 14 at the location of the bulb 52 because of this structural arrangement of parts movement of the diaphragm 42 and the dual control rods 48.