This valve is mainly used in air conditioning systems to maintain a constant pressure difference between the supply/return water pipelines, in order to improve system efficiency and ensure safety. 
Features: 
Installation and debugging are simple, and once adjusted, automatic control can be achieved, eliminating the need for valve sensors and complex transmission actuators, making maintenance convenient and less prone to malfunctions. 
Principle: 
The two control pipes of the pilot valve are respectively connected to the high-pressure source (supply pipe) and the low-pressure source (return pipe). When the high and low pressure difference is greater than the set value, the pilot valve opens and the main valve opens accordingly. Part of the high-pressure water flows directly back to the return water pipe through 800X. After the pressure difference is restored, 800X automatically closes.