mpo55Danfoss MP 55 Differential Pressure switches delay of relay 90 sec. 060B017291 Adjustment Cut out for falling pressure. Ambient temperature -40 - 60 °C. Ambient temperature -40 - 140 °F. Ammonia application No. Approval CCC, CE,The MP 55 was the first generation of the rubber tired variant of electric multiple units used on Paris's Métro system. The trains were manufactured by a consortium between Renault,