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Differential pressure switch


FSD series differential pressure controls (oil pressure control) protect the refrigeration compressor and other machineries. In refrigeration system, lubrication system must be kept in a certain oil pressure in order to get well lubrication for every part. If the oil pressure is too low, compressors will happen “Cylinder sticking” for losing oil in normal running or starting, even destroy bearing pad of the compressor.

The differential pressure control receives the signal of discharge pressure from lubricating oil pump and suction pressure from compressor. And it maintains the two pressures in a certain differential range. When the difference is lower than the setting one, the switch automatically cuts the compressor circuit off to stop running.

Approvals: CQC (China), CE (Europe).

FSD45C Differential Pressure controls is a derivative of other FSD series differential pressure controls,having the same function.However,Its micro switch accuracy is greatly improved and can control the compressor more effectively and efficiently.


 Technical data

Ambient temperature: -40  +65℃      Medium temperature: -40  120

 Available medium: R134a,R22,R407C,R404A/R507water, air and oil.

 Cable connection The cable entry can be used for 15mm dia.

 Electrical data


 Placing Order:

Any special requirements please remark behind the model number.

Inch connection size (7/16-20UNF), please state letter “E” after the model number.

“MGL” stands for capillary, standard length is 1m (including flare nuts), please mark the special length requirement.

“F” stands for “Internal thread connection”.

“M” expression external screw thread connection.

“A” stands for “Stainless steel air box assembly”.

 Type  Data(Unit:MPa)

 Mounting plate (Unit: mm)

 Contact form

 Dimension Unitmm)

* FSD-T series

Connection Introduction:

1. L2 and 22V bunch, and leads to contactor coil, and the other end

of the contactor is connected A phase.

2. the No.1 post of micro switch is connected to A phase

3.The accident lights, one end is connected to Post No.5, and the

other end is connected to neutral line

4. The normal signal lights, one end is connected to Post No.3, and the

other end is connected to neutral line

5. L1 is connected to neutral line