My sprayer is blowing air, but not drawing paint from the container?

The breather hole on the top of the suction tube is mostly likely blocked. Try removing the suction tube, cleaning thoroughly and once re-installed, give it another shot.

If that has not worked, it could be that the small blue diaphragm in the clear ventilation hose (on the top of the spray attachment) may have been installed upside down. Pop one end of this hose off, and re-install the diaphragm the other way.