Differential pressure switches

MP54 / MP55 / MP55A

MP54 and MP55 oil differential pressure switches are used as safety switches to protect refrigeration compressors against low lubricating oil pressure. If the oil pressure fails, the oil differential pressure switch stops the compressor after a certain time period. MP54 and MP55 are used in refrigerating systems using HCFC and non-flammable HFC refrigerants. MP55A is used in refrigerating systems with R717. MP55A can also be used in systems with HCFC and non-flammable HFC refrigerants. MP54 has a fixed differential pressure setting. It also incorporates a thermal time relay with a fixed release time setting. MP55 and MP55A have adjustable differential pressure and are available both with and without thermal time relay.

MP55E

MP55E oil differential pressure switches 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. MP55E for HCFC, HFC and HC refrigerants are equipped with gold-plated SPDT contacts, which react directly on the differential pressure without time delay.

The units are designed to operate in explosive zones acc. to 2014/34/EU, Atex directive, explosive zone 2, surface equipment, category 3.

MP55E are delivered with ¼ inch solder connections to ensure a hermetic installation.

RT

An RT pressure switch contains a pressure operated single-pole changeover contact, the position of which depends on the pressure in the inlet connection and the set scale value. The RT series includes pressure switches for general applications within industrial and marine refrigeration. The RT series also includes differential pressure switches, pressure switches for neutral zone regulation, and special pressure switches with gold-plated contact surfaces for PLC applications.