Pneumatic Flow Control Valve Manufacturer Supplies, Sales, Wholesale Prices, Which One is the Best? [Nantong Helu Building Materials Technology Co., Ltd.] The flow control valve is composed of a manual regulating valve group and an automatic balancing valve group. The function of the regulating valve group is to set the flow, while the function of the automatic balancing valve group is to maintain a constant flow. The flow control valve is suitable for water systems that require flow control, particularly for non-corrosive liquid media such as heating and air conditioning. Once installed in the water system, a pre-operation adjustment allows the system flow to automatically stabilize at the required set value.