Check of dust monitor vacuum pumps on 11/13/17 showed: 

End-X - Opened up air bypass to adjust pressure to 15 in/Hg.

End-Y - No changes all within spec.

CS - Opened up bypass just a little to fine tune pressure to 15 in/Hg. Pump is getting a bit noisy and there is carbon dust buildup on the filter. These are signs of wear on the vanes, and a pending rebuild. Have the rebuild kit in stock.