1. Zero Calibration Procedure

1.1 Setting Up the Detector for Calibration

1. Select the 3-way valve to the calibration direction.
2. Connect N₂ gas to the calibration line.
   • If using atmospheric air (ATM) instead of N₂ gas:
     • Disconnect the sampling line tube from the connector.
     • Set the zero detector to the sampling direction on the 3-way valve.

1.2 Accessing the Calibration Menu

1. Hold a magnet over the top center switch (√) on the detector display for 3 seconds, then remove it.
2. The display will show ‘SEt CAL’.
3. Place the magnet over ‘√’ again to enter the Calibration Menu.

1.3 Performing Zero Calibration

1. The display will show current gas reading (HC 0% LEL) with a flashing icon (’ ’).
2. Open the flowmeter until the detector indicates 500 cc/min of fresh air or N₂ gas.
3. Once the zero gas reading stabilizes, press ‘√’ to confirm zero calibration.
4. If successful, the display will show ‘Zero PASS’.
   • If unsuccessful, the display will show ‘Zero FAIL’, returning to configuration mode.
5. If zero-air was used, turn it off after completion.

2. Span Calibration Procedure

2.1 Initiating Span Calibration

1. The display will show ‘SPAn’ with ‘YES’ flashing.
2. To proceed with span calibration, press ‘√’.
   • If span calibration is not required, use ‘▲▼’ to select ‘No’, then press ‘√’ to exit.

2.2 Performing Span Calibration

1. The display will show the calibration span gas concentration while flashing the icon (‘ ’).
2. Use ‘▲▼’ to set the required span gas concentration (e.g., 50% LEL).
3. Connect the 3-way valve to the span gas cylinder.
4. Open the gas cylinder valve and apply the span gas to the sensor via the regulator.
5. Monitor the live gas reading on the display.
6. When the gas reading stabilizes, press ‘√’ to confirm span calibration.
7. If the sensor was replaced, the display will prompt:
   • Select ‘YES’ if the sensor was replaced.
   • Select ‘No’ if not replaced.
8. If span calibration is successful, ‘SPAn PASS’ will be displayed.
   • If calibration fails, ‘SPAN FAIL’ will appear, returning to configuration mode.

3. Completing Calibration & Returning to Normal Mode

3.1 Purging the Gas Sensor

1. The display will alternate between “Purg gAS” and the current gas reading.
   • This indicates the unit is expecting the span gas to be removed from the sensor.
2. Set the 3-way valve back to sampling direction.
3. Turn off the calibration span gas and remove the Sensepoint XCD Gassing Cap from the sensor.
4. Allow the gas to disperse.
5. When the gas reading falls below 50% of the calibration gas level, the display will initiate a countdown (up to 180 seconds depending on gas type).

3.2 Completing the Process

1. Once the countdown is finished, calibration is complete.
2. The detector will return to the ‘SEt CAL’ menu.
3. To exit, use ‘▲’ or ‘▼’ to select ‘QuIT’, returning the detector to normal monitoring mode.

⚠️ Important Notes

• Ensure proper gas flow during calibration (500 cc/min).
• Always return the 3-way valve to sampling mode after calibration.