FSD series differential pressure controls (oil pressure control) protect the refrigeration compressor and other machines. In the refrigeration system, the lubrication system must be kept at a certain oil pressure in order to receive well lubrication for every part. If the oil pressure is too low, compressors will experience “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. 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 it from running.
FP74E pressure differential control is usually used in the water system of central conditioning. It controls the pressure difference between water supply pipe and return pipe.
FP74E pressure differential control is equipped with a single-pole double-throw floating-point contact. The movement of floating-point will connect the contact plate to open or close the operating valve of motor drive.
One typical application is to mount the valve on the by-pass line near the system’s water pump. When the pressure difference between the system’s feeding and returning pipes is over the set value of the controller, the valve turns up and more water will flow through the by-pass valve. This then reduces the pressure difference between the feeding and returning pipes. On the opposite, the pressure differential will increase between these two pipes of the water system.
FSD-W series of differential pressure switches are used for flow control with flow control accuracy of HVAC. The system is resistant to water, and there are no requirements to pipe diameter and flow interference. This will replace any form of flow switch as the HVAC water system flow control, relative to the target type flow switch.
FSD-W series differential pressure switches are widely used in heat exchanges, tube heat water flow control, and condition monitoring of water pump and water filters. The import and export of differential protection is crucial.
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