MP 54 and MP 55 oil differential pressure controls are used as safety switches to protect refrigeration
compressors against low lubricating oil pressure. If the oil pressure fails the oil differential pressure
control stops the compressor after a certain time period. MP 54 and 55 are used in refrigerating systems
using fluorinated refrigerants. MP 55A is used in refrigerating systems with R717 (NH3). MP 55A can also
be used in systems with fluorinated refrigerant. MP 54 has a fixed differential pressure setting. It also
incorporates a thermal time relay with a fixed release time setting. MP 55 and 55A have adjustable differential
pressure and are available both with and without thermal time relay.
Data sheet/ Technical leaflet Pressure Control, type MP 54, MP 55, MP 55A