Field rule: Incorrect sample flow or air leakage will cause false
oxygen readings. Fix the sample system first.
Quick Checks (Before Detailed Troubleshooting)
- Confirm analyzer warm-up completed
- Verify sample flow and pressure
- Check for air leakage at fittings and valves
- Inspect filters for blockage
- Verify correct calibration gases
Symptom: High Oxygen Reading
- Check: sample system leaks (most common cause)
- Check: probe insertion depth
- Check: calibration drift
- Likely cause: air ingress or actual process upset
- Fix: leak test system, recalibrate, verify process conditions
Symptom: Low or Zero Oxygen Reading
- Check: sample flow restriction or blockage
- Check: sensor response with span gas
- Check: condensation or contamination
- Likely cause: sensor aging, blocked sample path
- Fix: restore flow, clean sample system, replace sensor if required
Symptom: Unstable / Noisy Signal
- Check: sample pressure fluctuation
- Check: moisture in sample gas
- Check: grounding and shielding
- Likely cause: sample instability or electrical noise
- Fix: stabilize pressure, improve drainage, correct grounding
Symptom: Calibration Failure
- Check: correct zero/span gas and regulator
- Check: leaks in calibration manifold
- Check: sufficient warm-up time
- Likely cause: incorrect gas, leaking valve, sensor degradation
- Fix: verify gases, leak test, repeat calibration