mpo55Danfoss MP 55 Differential Pressure Switch is used in refrerating systems with R717 and also systems with HCFC and non-flammable HFC refrerants. MP 55 Pressure Switch has a fixedDanfoss 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,