OX400 — Probe Fouling / Plugging (Decision Tree)
Use when response is slow, unstable, or readings drift due to dust/ash buildup.
Symptoms: slow response, unstable readings, calibration difficulty, frequent drift.
Decision Tree
1) Confirm fouling present
Inspect probe tip/filter cap for ash/dust buildup, sintered filter blockage, sticky deposits.
Inspect probe tip/filter cap for ash/dust buildup, sintered filter blockage, sticky deposits.
2) Purge system working?
If purge is equipped: confirm purge air pressure/flow, purge valve operates on schedule. Fix purge first.
If purge is equipped: confirm purge air pressure/flow, purge valve operates on schedule. Fix purge first.
3) Clean/replace protective cap/filter
Clean as per maintenance practice. If damaged or permanently blocked → replace.
Clean as per maintenance practice. If damaged or permanently blocked → replace.
4) Check installation location
Severe dust zones may need relocation, longer/shorter insertion depth, or improved shielding.
Severe dust zones may need relocation, longer/shorter insertion depth, or improved shielding.
5) After cleaning
Allow stabilization time, then run verification/calibration if needed.
Allow stabilization time, then run verification/calibration if needed.
6) Fouling repeats quickly
Increase purge frequency (if allowed), improve filtration/conditioning, or review process dust issues.
Increase purge frequency (if allowed), improve filtration/conditioning, or review process dust issues.
Good Practices
- Schedule routine cleaning in dusty service
- Ensure purge air is dry/clean
- Keep cal manifold leak-free (prevents false drift)