Danfoss Externally Operated Relief Valves - 032U7190, 032U7191, 032U7192 Danfoss EV220X (EVSI)spec. valves were origionally designed for the fire sprinkler system manufacturers as water operated relief valve. Types: EV220X 15B G 1/2E UN000 (EVSI 15) Spec. 032U7190 EV220X 20B G 3/4E UN000 (EVSI 20) Spec. 032U7191 EV220X 25B G 1E UN000 (EVSI 25) Spec. 032U7192 --------------------------------------------------------------------------------------------------------------------------