As established in the previous puzzle, the Tech knew that two-stage pumps can reach a lower pressure value and thus her suspicion that the plots were mislabeled was correct. The graphic below reflects that correction. Now attention can shift to the additional message presented in the plots below.

As indicated in Puzzle 39, the technician also understands the concepts of “outgassing” (a vacuum system is “outgassing” when the vacuum pump is “pulling” gas molecules from the materials in the vacuum chamber) and an actual vacuum chamber leak (a vacuum system is “pulling” gas molecules from outside the vacuum chamber into the vacuum chamber). After measuring the values for current drawn through and voltage drop across the motor of the single stage pump, the tech determined that the single stage pump is operating within manufacturer’s specifications.