HF tools are notoriously poor quality and pressure blasters are notoriously temperamental. Put the two together and... well, you know. I bought a small cabinet blaster from HF and had to re-engineer the POS to get it to work... but it was inexpensive as well as cheap.
I used a syphon blaster and it worked well... a little slow but it didn't clog much and when it did I just held my finger over the nozzle and gave it a blast to clear the obstruction.
Sounds to me like the trigger mechanism is defective if no air is coming through. Take all the blasting media out of it and try it like that. If no air comes through take it back and get your money back.
Good luck.
