The controller is a self-acting differential pressure controller with flow limitation primarily for use in district heating systems. The controller closes on rising differential pressure or when set max. flow is exceeded.The controller has a control valve with adjustable flow restrictor, an actuator with one control diaphragm and spring for differential pressure setting.Further on two valve versions are available:∙ VFQ 22 with metallic sealing cone∙ VFQ 221 with soft sealing coneTogether with Danfoss intelligent electrical actuator AMEi 6 intelligent optimization functions are available:∙ iSET-intelligent substation efficiency optimization∙ iNET-intelligent network balancing