Calibration = Quality of gas + delivery + stability
A calibration failure is rarely “software”. It is usually caused by one of: wrong gas, bad regulator, leaks, restriction, or insufficient warm-up.
Good calibration checklist
- Analyzer warmed up and stable
- Correct zero/span gases (in-date, correct concentration)
- Regulator stable (no hunting)
- Calibration solenoids switching correctly
- No leaks in manifold and tubing
- Reading stabilizes within expected time
- Repeat check matches previous results
Common causes of calibration failure (field)
Wrong Gas / Wrong Concentration
Most common. Always verify cylinder label and DAHS configuration.
Leak in Cal Manifold
Causes unstable zero/span and slow stabilization.
Restriction / Low Flow
Gas cannot reach analyzer properly → unstable readings.
Moisture / Condensation
Water carryover affects NDIR/UV and causes drift/noise.
Best practice: After calibration, verify with a second stable run
or compare trend stability before declaring “system OK”.