GVDA AS8900 Multi-Gas Monitor User Manual

1. Introduction

The GVDA AS8900 Multi-Gas Monitor is a portable and handheld instrument designed for continuous and simultaneous monitoring of four gases: Oxygen (O2), Combustible Gas (LEL), Carbon Monoxide (CO), and Hydrogen Sulfide (H2S). All gas readings are displayed on a single LCD screen. The unit allows users to configure high and low alarms, as well as Time Weighted Average (TWA) and Short Term Exposure Limit (STEL) alarms. The device provides both audio and visual alarms, along with vibration, when an alarm condition is exceeded.

Figure 2: Front view of the AS8900 Multi-Gas Monitor display.

2. Safety Information

2.1 Cautions and Warnings

• Always read and follow all procedures and conditions outlined in this manual to prevent instrument failure.
• In environments with insufficient oxygen, combustible gas readings may be lower than actual corrected readings.
• In environments with enriched oxygen, combustible gas readings may be higher than actual corrected readings.
• The instrument must be re-calibrated if it has been used in an area where silicon vapors were present.
• Ensure the sensor opening and water barriers of the instrument are always kept clean.
• Oxygen readings may experience temporary fluctuations when the atmospheric pressure changes suddenly.
• Do not charge the battery or service the unit in hazardous or enriched atmospheric conditions.
• This instrument is recommended for use and service only by qualified personnel who have fully read and understood this instruction manual.
• Caution: High off-scale readings indicate that the environment may have reached an explosive concentration, which is a dangerous signal indicating a hazardous area.

2.2 Effects of Oxygen Levels

2.3 Harm of Carbon Monoxide

* The above parameters are for reference only.

3. Unit Packing and Contents

The gift box should contain the following items:

4. Product Specifications

4.1 Sensor Specifications

4.2 Environmental and Physical Specifications

• Operating Temperature: -10~50°C (except LEL sensor: 0~40°C)
• Operating Humidity: 15~95% RH, typical
• Storage Temperature: 0~40°C
• Size: 120.20mm x 64.50mm x 38.30mm
• Weight: 200g

4.3 Battery Specifications

• Type: Rechargeable Lithium-ion battery, 3.7 Volts
• Working Runtime: 18 hours (typical, without AS8930 sampling pump, in room temperature and no alarm conditions).
• Working Runtime with AS8930 Sampling Pump: 12 hours (typical, in room temperature and no alarm conditions).

5. Operation Manual

5.1 Instrument Operation

1. To Turn On: Depress and hold the button for over 1 second. The unit will turn on with a beep sound and vibration, and the LCD will light up with all icons and segments. After an 18-second software countdown, the unit will enter Gas Monitoring mode.
2. To Turn Off: Depress and hold the button for over 3 seconds. The unit will power off after 3 beep sounds.
3. Backlight Control: Depress the button to turn the LCD display backlight on or off.

5.2 Gas Monitoring Mode

• Upon power-on, the display will show all four gas symbols with their respective readings.
• The unit continuously monitors and displays gas readings. As gas levels increase, the corresponding concentration will be shown.
• A battery life indicator is displayed in the upper left corner. The shaded portion of the battery icon decreases as battery life depletes.
• If gas concentration exceeds the high or low alarm limit (including TWA or STEL), the unit will trigger an audio and visual alarm with vibration.

5.3 Zero/Calibration Mode

This mode is used for zeroing and calibrating the instrument. The instrument is recommended to be calibrated for sensitivity with 25% or 50% of full concentration pentane or methane.

1. From Gas Monitoring mode, depress the button once to enter Zero/Calibration mode.
2. In this mode, the and icons will be displayed along with the 4 gas readings.
3. To start the Zero/Calibration process, depress the button. The CO, H2S, and LEL sensors will be zeroed first, followed by Oxygen sensor SPAN calibration.
4. During this process, the "CLOCK" icon and full Oxygen span value will be displayed.
5. Once completed, the display will show "SPAN" and the icon.
6. To calibrate remaining sensors, depress the button.
7. The calibration gas should be a blended cylinder containing 25ppm H2S, 100ppm CO, 25% or 50% LEL Methane or pentane, and 19% Oxygen at 0.5 LPM flow speed.
8. If calibration fails (indicated by 'F' on display), recalibrate. Do not enter calibration mode without standard gas, as preset values may be deleted.

Figure 3: Gas cylinder connection for instrument calibration.

5.4 Peak Value Setting Mode

• From Zero/Calibration mode, depress the button to enter Peak Value setting mode.
• The display will show 3 gas peak readings and the lowest oxygen sensor reading, along with "PEAK" and "ENTER" icons.
• Depress the button to reset all peak values of the current readings.
• Depress the button to proceed to TWA Value mode.

5.5 TWA Value Mode

• In Gas Monitoring mode, depress the button for the third time to enter TWA (Time Weighted Average) value mode.
• The display will show the "TWA" icon and only 2 hazardous and combustible gas sensor readings.
• TWA values are reset each time the unit is powered off. The time base for TWA calculation is set for 8 hours.

5.6 STEL Value Mode

• In Gas Monitoring mode, depress the button for the fourth time to enter STEL (Short Term Exposure Limit) value mode.
• The display will show the "STEL" icon and only 2 hazardous and combustible gas sensor readings.
• STEL values are reset each time the unit is powered off. The time base for STEL calculation is set for 15 minutes.

5.7 Configuration Mode

This mode allows the user to change high, low, TWA, and STEL alarm levels, as well as the security code.

1. To enter: Depress the or buttons simultaneously during the 18-second software countdown time after power-on.
2. Once in Configuration Mode, the security code screen will be displayed. The preset code is 123.
3. The first digit of the code will flash. Use the or buttons to change the digit, then depress the button to set the second and third digits.
4. Once the security code is set and confirmed, depress the button to escape to other alarm setting modes.

5.8 Low Alarm Setting Mode

• This is the first configuration screen. The display will show speaker, down, and enter icons along with the four low alarm set readings for each gas.
• If no change is required, press the button to move to the next setting mode.
• To change a value: Press the button; the first gas low alarm value will flash. Adjust with or .
• Once confirmed, press the button to proceed to the next gas low alarm setting.
• Continue this procedure until all 4 gas low alarm values are set. The display will show speaker, down, and enter icons along with the 4 new low set alarm values.
• Depress the button to re-enter this setting mode for further adjustment if required.
• Pressing the button will move the setting to High Alarm Setting Mode.
• Depress the button to return to Low Alarm Setting Mode without saving changes.
• Depress the button a second time to return to the original gas monitoring mode.

5.9 High Alarm Setting Mode

• This is the second configuration screen. The display will show speaker, down, and enter icons along with the four high alarm values for each gas.
• If no change is required, press the button to move to the next setting mode.
• To change a value: Press the button; the first gas high alarm value will flash. Adjust with or .
• Once confirmed, press the button to proceed to the next gas high alarm setting.
• Continue this procedure until all 4 gas high alarm values are set. The display will show speaker, down, and enter icons along with the 4 new high set alarm values.
• Depress the button to re-enter this setting mode for further adjustment if required.
• Pressing the button will move the setting to TWA Alarm Value Setting Mode.
• Depressing the button to return to High Alarm Setting Mode without saving changes.
• Depress the button a second time to return to the original gas monitoring mode.

5.10 TWA Alarm Value Setting Mode

• If no change is required, press the button to move to the next STEL alarm setting mode.
• To change a value: Press the button; the first gas low alarm value will flash. Adjust with or .
• Once confirmed, press the button to proceed to the next gas TWA alarm setting.
• Continue this procedure until 2 gas TWA alarm values are set. The display will show speaker, TWA, and enter icons along with the 2 new TWA alarm values.
• Press the button to re-enter this setting mode for further adjustment if required.
• Pressing the button will move the setting to the next STEL alarm setting mode.
• Pressing the button to return to original TWA alarm mode without saving changes.
• Pressing the button a second time to return to the original gas monitoring mode.

5.11 STEL Alarm Setting Mode

• The display will show speaker, STEL, and enter icons along with 2 STEL alarm values.
• If no change is required, press the button to move to the next setting screen.
• To change a value: Press the button; the first STEL alarm value will flash. Adjust with or .
• Once confirmed, press the button to proceed to the next gas STEL alarm setting.
• Continue this procedure until 2 STEL alarm values are set. The display will show speaker, STEL, and enter icons along with the 2 new STEL alarm values.
• Press the button to re-enter this setting mode for further adjustment if required.
• Pressing the button will move the setting to the next setting mode.
• Pressing the button to return to original STEL alarm mode without saving changes.
• Pressing the button a second time to return to the original gas monitoring mode.

5.12 Security Code Setting Mode

• This mode is accessed after the LEL setting mode. The display will show "(enter) (up/down/enter)" and the manufacturing preset security code (123).
• If no change is required, press the button to move to other LEL setting modes.
• To change the security code: Press the button, and the preset code will flash.
• Adjust the first digit using the or buttons. Once the value is confirmed, press the button to set the second digit.
• Continue this procedure until all three digits are set. The display will show "(enter) (up/down/enter)" icons along with the new security code.
• To make further changes, press the button to re-enter this setting mode.
• If no change is needed, press the button to move to the next LEL setting mode.
• Pressing the button will return you to the security mode again, with no changes saved.
• Pressing the button a second time will return the display to normal gas monitoring mode.

5.13 LEL Setting Mode

• LEL is the final configuration setting mode. After pressing the button, the LEL value readings will flash.
• Press the or button to set the new percentage between 25% and 50%.
• Once the setting is finished, the new setting value will show on the display, then press the button to confirm.
• Pressing the button will return the unit to the normal gas monitoring mode.
• If the button is pressed, it will return to the first setting mode again.
• Remarks: LEL refers to the low explosion level of combustible gas in normal air.

5.14 Accessory AS8930 Sampling Pump

• The AS8930 external sampling pump is compatible with all AS8900 series gas monitors. Note that it is not included in every unit pack.
• The pump mounts into the AS8900 unit using 2 fasten screws. Refer to the assembly drawing for detailed instructions.

6. Maintenance

The following guidelines should be followed to ensure good maintenance of your AS8900 unit:

6.1 Cleaning

• If necessary, wipe the outside surface of the unit with a soft, clean cloth.
• Never use any solvents or cleaning solutions.
• Ensure the rubber buttons are free of dirt.
• To clean the sensor opening, use a clean, soft cloth or soft brush.

6.2 Charging the Battery

• The lithium-ion battery should be fully charged before using the AS8900.
• To charge the battery, plug the connecting lead wire of the battery charger into the charging port located at the bottom of the unit. This port is protected by a rubber flap, which needs to be released before charging.
• The battery should be fully charged within 6 hours.
• Once fully charged, the unit will operate for approximately 18 hours, and about 12 hours when used with the AS8930 external sampling pump.
• The shaded area of the battery indicator shows full when the battery is fully charged.
• If only one bar of the shaded area remains, the battery needs to be charged immediately.
• When the battery is low, the unit may emit a periodic alarm sound to alert you to charge the unit.

7. Troubleshooting

This section provides general troubleshooting tips. For specific error codes or persistent issues, refer to the calibration section or contact customer support.

• Calibration Failure ('F' on display): If the display shows 'F' during calibration, it indicates a failure. Recalibrate the instrument following the steps in Section 5.3. Ensure a standard gas cylinder is properly connected and the correct security code is used.
• Inaccurate Readings: Ensure the sensor opening and water barriers are clean (Section 6.1). Verify that the instrument has been calibrated recently, especially if used in environments with silicon vapors (Section 2.1, 5.3).
• Battery Draining Quickly: Ensure the battery is fully charged (Section 6.2). If the issue persists, the battery may need replacement (refer to warranty information).
• No Display/Unit Not Turning On: Check battery charge level. Ensure the power button is held for the correct duration (Section 5.1).
• Alarm Not Functioning: Verify alarm settings in Configuration Mode (Section 5.7) and specific alarm setting modes (Sections 5.8-5.11).

8. User Tips

No specific user tips were available from reviews or Q&A. However, general best practices for gas monitors include:

• Regularly check battery levels before use.
• Perform bump tests or full calibrations as required by your industry standards or local regulations.
• Store the device in its carrying pouch when not in use to protect it from dust and physical damage.
• Familiarize yourself with the alarm thresholds for the gases you are monitoring.

9. Warranty and Support

9.1 Warranty

• The AS8900 Multi-Gas Monitor is warranted to be free from defects in material and workmanship for a period of one year from the date of purchase.
• This warranty does not include the sensor and battery pack after 6 months from the purchase date.

9.2 Manufacturing Statements

Thank you for purchasing and using the Smart Sensor AS8900 Multi-Gas Monitor. This unit has been designed, manufactured, tested, and proven by a professional quality team. The unit is expected to be reliable with reasonable care and maintenance as described in this instruction manual.

9.3 Enclosures and Environmental Information

• Used or non-functional batteries should be disposed of according to international environmental regulations.
• Smart Sensor reserves the right to modify or change the design of the unit, operation manual, or product specifications without prior notice.

For further assistance or support, please refer to the official GVDA website or contact your local distributor.

10. Frequently Asked Questions (FAQ)

No specific FAQ content was available. Please refer to the relevant sections of this manual for operational details or contact customer support for further inquiries.