Brushless DC pumps can adjust flow and pressure in the following ways:

1. Voltage regulation: The flow and pressure of brushless DC pumps are usually related to the supply voltage. By adjusting the voltage received by the pump, the running speed and output capacity of the pump can be controlled, which in turn affects the size of the flow and pressure. Reducing the voltage can reduce the speed and power of the pump, thereby reducing the flow and pressure; increasing the voltage can increase the flow and pressure.

2. PWM modulation: Pulse width modulation (PWM) is a common method for regulating the flow and pressure of brushless DC pumps. By changing the duty cycle of the power supply voltage, that is, changing the time ratio of the high level and the low level, the average voltage of the pump can be controlled. By adjusting the duty cycle and duty cycle of PWM, the flow and pressure of the pump can be accurately controlled within a certain range.

3. Variable speed controller: Some brushless DC pumps are equipped with variable speed controllers, which can directly adjust the running speed of the pump through the controller to adjust the flow and pressure. Variable speed controllers usually provide speed adjustment functions with preset options or continuous adjustment, allowing users to flexibly adjust the output of the pump according to actual needs.

4. Adjusting valves or nozzles: In some applications, adjusting valves or nozzles can be used to control the flow and pressure of DC brushless water pumps. By adjusting the opening of the valve or the size of the nozzle, the flow and pressure of the water pump output can be changed. This method is usually suitable for scenarios that require continuous or large-scale adjustment.

It should be noted that different models and brands of DC brushless water pumps may have different adjustment methods and control options. In actual applications, the corresponding adjustment method can be understood and operated according to the specific water pump model and product manual.