The oxygen analyzer monitors nitrogen purity in real time, so keeping it properly configured is critical for accurate readings and reliable performance. This article is the calibration procedure. To confirm the analyzer is reading correctly against a known gas, see the separate verification article. Verify accuracy at least once a year, and any time purity readings look inconsistent with expected performance, particularly after a preventive maintenance event.
In this guide
Understanding your analyzer hardware
Older nitrogen generators route the sample line directly to the O2 sensor. Newer units include an upgraded analyzer assembly with an integrated regulator and flow control valve, which stabilizes gas flow across the sensor and produces more consistent readings. The calibration procedure below applies to both configurations. If you are unsure which assembly your unit has, contact our support team before proceeding.
Calibration set points (current standard)
Based on updated engineering guidance, PSA nitrogen generators are calibrated using factory-defined set points. These values are validated to produce accurate purity readings without using calibration gas to derive raw sensor values.
For PPM units, enter the following values in the calibration menu:
| Field | Value |
|---|---|
| Low Raw | 819 |
| High Raw | 4095 |
| Low Cal | 0 |
| High Cal | 1000 |
Accessing the calibration menu
- Turn the generator to the OFF position.
- Close the ball valve on the sample line at the nitrogen storage tank.
- Disconnect the sample line from the sample port on the outside of the electrical cabinet.
- On the controller display, press Menu.
- Enter password 6557 and press the Return key (bottom-right button).
- Select Sensor Setup / Calibration.
- Select O2 PPM/% Calibration.
Entering calibration values
PPM units. Enter the factory set points from the table above: Low Raw 819, High Raw 4095, Low Cal 0, High Cal 1000.
Percentage (%) O2 units. For units configured to display in percent rather than PPM, calibration gas values are still entered:
- Enter the concentration value from your test gas canister (typically 1%) into the "0–2% O2 Calibration Gas" field.
- Enter 20.9% into the "20–22% O2 Calibration Gas" field.
Need test gas? Contact us at the number or email below to request a quote.
Completing the procedure
- Exit the calibration menu and return to the main screen.
- Reconnect the sample line to the sample port on the electrical cabinet.
- Open the ball valve at the nitrogen storage tank to resume normal nitrogen flow to the analyzer.
- Restart the generator and allow the system to fully cycle before evaluating purity output.
After calibrating, confirm the analyzer is reading correctly using certified test gas. See How do I verify my analyzer is working correctly?
Purity issues after preventive maintenance
If your system was producing acceptable purity before a PM and purity has since dropped, analyzer calibration is one of the first things to check. Common post-PM causes include:
- Calibration values altered or reset during the PM.
- Pilot regulator disturbed during reassembly. Confirm pilot pressure is in the 90–100 PSI range at the controller.
- New CMS material added to the beds. The beds may need additional cycle time to equilibrate after a top-off or full media replacement.
- Sample line reconnected improperly, allowing ambient air to influence the sensor reading.
If recalibrating the analyzer does not restore expected purity, contact our support team to schedule a remote diagnostic session or field visit.
Related Articles
- How do I verify my analyzer is working correctly?
- Quick Check Sensor & How to Perform Purity Readings
- How Frequently Should I Measure My CMS Levels and What's the Process?