PMR service analyzer. Clean up flange, sample line, filter probe, balston filter, diaphragm pump, dryer gas from dirty of coal. Check filter humidity sensor, replace filter if found bad condition. Calibration zero CO and span O2 at L63 2K1 because before measurement CO -0.002 PPM and O2 22.45 Vol% after calibration reading CO: 0.042 PPM O2: 18.10 Vol % ( AGUS & ADI )