Sample path (think in blocks)
Stack/Process → Probe → Heated Line → Filter(s) → Pump/Flow Control →
Conditioning (chiller/dryer) → Analyzer → Vent/Return
Most common field failures
Probe Plugging
Low flow, slow response, unstable readings. Usually dust/ash/salts buildup.
Cold Spots / Heater Failure
Condensation forms, causing drift, noise, corrosion, and repeated calibration failure.
Filter Restriction
Pressure drop increases, pump works harder, response time becomes slow.
Leaks (Air Ingress)
False O₂, dilution of gas analyzers, unstable baseline. Leak test is mandatory.
Technician troubleshooting method (sample system)
- Confirm flow at analyzer inlet (not just pump running)
- Check filters and DP (if available)
- Inspect chiller temperature and drain
- Check heated line temperature and continuity
- Perform leak test (calibration manifold + sample path)
- Verify stable readings using calibration gas
Rule: If response is slow, fix flow restriction first.
If readings drift, suspect condensation/leaks before electronics.