UPDATE #1 - After originally writing this review, my third blockage also died on me. I ran additional diagnostics on each unit and found that the faults were not in the reset buttons, but in the relay that turns on the vacuum circuit when the unit is powered by the tool circuit. I contacted IVAC Technical Support and was granted a return authorization and directed to ship the units to a repair facility in upstate New York. That's how it is now. When the refurbished units return I will provideโฆ