VGU and VGUF are pressure relieved 2-way normally closed (NC) valves, designed to be combined with: AVT Temperature actuators; AMV(E) 20 / AMV(E) 30 electrical actuators; AMV(E) 23 / AMV(E) 33 electrical actuators with spring return function. In combination with AVT temperature actuators and AMV(E) electrical actuators, valves can be used primarily in cooling systems.