I purchased a VX230GA and installed it in order to use it for an air blow, but air did not come out.

As you pointed out, the maximum operating pressure difference of the VX230GA is 0.1 MPa. When the supply pressure is 0.4 MPa, if the supply pressure immediately after the OUT side piping of the 2 port valve is not 0.3 MPa or more, the valve cannot operate. In the case of the VX2 series (although the flow decreases), consider the use of a valve whose maximum operating pressure difference is 0.4 MPa or more, or consider changing over to the VXD or VXZ series.