Proflow's Vacuum adjustable safety switches have been designed to,for example sense when vacuum drops below a specific minimum set point and activates vacuum pump, or wired to activate a water/methanol injection when vacuum drops below the set point. This heavy-duty vacuum switch is made of premium materials to serve as a quality replacement. Note: Choice of Normally Open or Normally Closed wiring Factory Pre Set To 20"hg Will switch on OR off at set point Set point is adjustable from 18-22hg +-3hg Clockwise raises the set point /Anti Clockwise lowers the set point - Do not touch the rubber cap as this set screw does not apply
