The Milwaukee result is credible, maybe slightly high but depends on temperature. If your meter always read around 27ppm on tap water even before you calibrated it, then there certainly sounds to be a problem.
Just to confirm, you are regulating the gas flow rate before the meter and flowing this through with no restriction at the outlet side?
Just to confirm, you are regulating the gas flow rate before the meter and flowing this through with no restriction at the outlet side?
Comment