this is the new vac switch i installed after reading about them on this site. Grainger item #4XB70 Air Sensing Switch, General Purpose, SPDT, Pressure Setting Range 0.12-5.0 In WC, Integral Barbed Sample Line Connector, Differential 0.08 WC, Operating Temp Range -40 To 180 F, Electrical Rating 300 VA Pilot Duty, UL Listed, CSA Certified I adjusted the switch all the way counter clockwise to the lowest setting. according to the directions. Could the door seal be bad??