The principle of the balancing valve is the counter-regulation in the valve body. When the pressure at the inlet is increased, the diameter is automatically reduced, and the flow rate is reduced, and vice versa. If reversed, this adjustment system will not work. Moreover, the regulating valve plate is directional, and the reverse pressure can even reduce or even close the flow. Since the balancing valve is installed for better heating, there is no problem with reverse loading. If it is a counter-installation, it is a human error, and of course it will be corrected. The balancing valve belongs to the category of regulating valve. Its working principle is to change the flow resistance of the fluid flowing through the valve by changing the gap between the valve core and the valve seat (ie opening degree) to achieve the purpose of regulating the flow. The balancing valve is equivalent to a throttling element whose local resistance can be changed. For an incompressible fluid, it is available from the flow equation.