What mistakes do people make when choosing VFD pump inverter?

People might choose the wrong VFD / VSD Constant Pressure Booster Pump Inverter which have bad features as below:

- Difficult to assemble with water pump

- The size of the final VFD / VSD Inverter Constant Pressure Pump system is too big for the space

- The VFD / VSD Constant Pressure Booster Pump Inverter cannot work suitably with the water pump.

- Difficult installation and pipe work

- Provide not constant and not stable water pressure

- Low energy saving rate

- Cannot reduce pump operating noise

- Not enough protection for water pump

- Not clear indication for setting pressure, current pressure, and various error status

- Not easy to set parameters