Does anyone have experience with this? I have a portable one (Alloy Pressure Drive), and it works great, so I bought a floor pump. The chuck on the Floor Drive threads tightly onto the presta valve, but when I start pumping, air just get blown out and not into the tube. I have used the schrader chuck on my car tire and it pumps fine also.

I switch the chuck from the Pressure Drive (presta/schrader on each end of a tube) on the the Floor Drive and it works perfectly.

Any suggestions? Is the chuck on the Floor Drive defective?

Thanks...