CEM GD-3308 Combustible Gas Leak Detector User Manual

1. Introduction

The CEM GD-3308 Combustible Gas Leak Detector is a gas leak locating tool designed to identify the presence and source location of combustible gases. It measures concentrations between 0 and 10000 parts per million (PPM).

The detector utilizes an internal sensor that heats during operation. As the heated sensor interacts with gases, the unit provides immediate indications of combustible gases through visual, audio, and vibration feedback mechanisms. It can detect various combustible gas concentrations, from 1-1000ppm to 0-10000ppm, by setting high and low concentration detection levels. When gas is detected, the LCD display shows the concentration, and appropriate audible and vibration alerts are triggered.

The GD-3308 comes equipped with an attached flexible 16-inch probe hose for precise detection.

Figure 1: CEM GD-3308 Combustible Gas Leak Detector

2. Safety Information

2.1. Safety Symbols

This section explains the safety symbols and signal words used in this manual and on the product:

• DANGER: Indicates a hazardous situation which, if not avoided, will result in death or serious injury.
• WARNING: Indicates a hazardous situation which, if not avoided, could result in death or serious injury.
• CAUTION: Indicates a hazardous situation which, if not avoided, could result in minor or moderate injury.
• NOTICE: Indicates information that relates to the protection of property.
• Read Manual Symbol: This symbol means read the operator's manual carefully before using the equipment. The manual contains important information on safe and proper operation.

2.2. General Safety Rules

1. Work Area Safety: Keep work area clean and well lit. Do not operate in explosive atmospheres. Keep children and bystanders away.
2. Electrical Safety: Avoid body contact with earthed or grounded surfaces. Do not expose equipment to rain or wet conditions.
3. Personal Safety: Stay alert and use common sense. Do not operate under the influence of drugs or alcohol. Always wear eye protection and other appropriate PPE. Maintain proper footing and balance.
4. Equipment Use and Care: Use the correct equipment for your application. Do not use if the switch is faulty. Disconnect batteries before adjustments or storage. Store idle equipment out of reach of children.
5. Maintenance: Maintain equipment, check for damage. Have damaged equipment repaired. Use only manufacturer-recommended accessories. Keep handles dry and clean.

2.3. Specific Safety Information for Combustible Gas Detector

• High concentrations of combustible gases can cause explosions, fires, asphyxia, and other hazards. Understand the gas characteristics and use proper precautions.
• Always turn on and calibrate the gas detector in an area known to be free of combustible gases. Incorrect calibration can lead to inaccurate readings and undetected gases.

3. Specifications

3.1. General Specifications

3.2. Measurable Gases

The GD-3308 can detect a wide range of combustible gases, including:

• Methane (Natural Gas)
• Hydrogen
• Carbon Monoxide
• Propane
• Ethylene
• Ethane
• Hexane
• Benzene
• Iso-Butane
• Ethanol
• Acetaldehyde
• Formaldehyde
• Toluene
• P-Xylene
• Ammonia
• Hydrogen Sulfide

Natural Gas typically consists of a high percentage of methane and smaller percentages of propane and other gases.

4. Controls & Display

Figure 2: Front view of the GD-3308 with labeled controls.

4.1. Display Elements

• LCD Display: Shows gas concentration (PPM, LEL), battery status, and other indicators.
• Battery Display: Indicates current battery level.
• Article Simulation Indications: Visual representation of gas levels.
• Combustible Gas Concentration Display: Shows PPM and LEL values.
• Gas Explosion Limitation: Indicates the lower explosive limit (LEL).
• High Sensitivity Selector: Indicates when high sensitivity mode is active.
• Low Sensitivity Selector: Indicates when low sensitivity mode is active.
• CAL (Calibration) Icon: Appears during calibration.
• RESET Icon: Appears when restoring factory settings.

4.2. Control Buttons

• ON/OFF Button: Powers the unit on or off.
• Auto Zero Enable/Disable Button: Activates or deactivates the auto-zero function.
• High/Low Sensitivity Button (H/L): Toggles between high and low sensitivity modes.
• Auto Power Off Enable/Disable Button (APO): Activates or deactivates the automatic power-off feature.
• BackLight Enable/Disable Button: Turns the display backlight on or off.
• Audible Alert Enable/Disable Button: Turns the audible alarm on or off.
• Vibration Alert Enable/Disable Button: Turns the vibration alarm on or off.

5. Setup

5.1. Pre-Operation Inspection

Before each use, inspect your GD-3308 to ensure proper function and reduce risk of injury or incorrect measurements:

1. Clean any oil, grease, or dirt from the equipment.
2. Inspect for broken, worn, missing, misaligned, or binding parts, or any other condition that may prevent safe operation.
3. Check that all warning labels are present, firmly attached, and readable.
4. If any issues are found, do not use the detector until it has been properly serviced.
5. After setup and operation, turn ON and calibrate the gas detector. Confirm it senses gas using a combustible gas source (e.g., unlit lighter). If not, service the unit. Remove the gas source and allow the sensor to stabilize before use.

5.2. Initial Setup and Operation

WARNING: High concentrations of combustible gases can cause explosions, fires, asphyxia, and other hazards. Always calibrate in a gas-free area.

1. Ensure an appropriate work area as indicated in the General Safety Section.
2. Confirm the detector is suitable for your application. Refer to the Specifications section for sensitivity and detectable gases.
3. In a gas-free area, turn on the detector by pressing and releasing the ON/OFF button for one second. The detector will vibrate and beep.
4. The sensor will warm up for approximately 40 seconds, displaying a countdown. Once complete, it will beep and vibrate, then display current gas concentration values, gas explosion limitation, and max gas concentration values.
5. If the battery icon is empty, the battery needs charging. If the LCD flashes and beeps, the sensor has failed and requires service.
6. If left ON for more than ten minutes with no activity and Auto Power Off is enabled, it will automatically shut off.

6. Operating Instructions

6.1. Gas Detection

1. After initial setup and calibration, enter the area to be monitored.
2. Pay close attention to the gas level indicators on the LCD. As gas levels increase, the displayed values will rise, and the frequency of the Audible Alert beeping and Vibration Alert will increase.
3. To locate a leak, use the gas detector to find areas of lower gas concentration and follow back to the source. For piping systems, trace the system, stopping at joints to monitor gas levels.

6.2. Sensitivity Adjustment

• In low sensitivity mode, the lowest detectable methane concentration is 10ppm.
• Switch to high sensitivity by pressing the High/Low Sensitivity (H/L) button. In high sensitivity mode, the lowest detectable methane concentration is 100ppm.
• Sensitivity can be changed at any time by pressing the H/L button.

6.3. Backlight, Auto Zero, and Auto Power Off

• BackLight: Press and release the BackLight button to toggle it ON or OFF.
• Auto Zero: Press and release the Auto Zero button to enable or disable. This function quickly adjusts the sensor's zero point, improving sensitivity and reducing interference from unknown gases.
• Auto Power Off: Press and release the APO button to enable or disable. If enabled, the detector will automatically shut off after 10 minutes of inactivity to conserve battery.

6.4. Gas Detector Feedback for Methane Concentration Levels

Gas Concentration levels may differ depending on the specific gas detected.

7. Battery Information

WARNING: Do not charge or replace batteries in the presence of combustible gas concentrations to avoid fire, explosions, and serious injury.

The GD-3308 has a built-in Polymer Li-Ion battery that does not require replacement under normal use. If the battery is low, use a 5V/1A adapter to charge the unit. Do not operate the unit while it is charging.

For long-term storage or transportation, remove the battery to prevent potential leakage.

8. Maintenance

8.1. Cleaning

Do not immerse the detector in water. Wipe off dirt with a damp, soft cloth. Do not use aggressive cleaning agents or solutions. Treat the instrument with care, similar to a delicate optical device.8.2. Sensor Calibration & Replacement

The GD-3308 requires no calibration beyond the initial startup procedure. If the sensor fails, it can be replaced.

8.2.1. Manual Calibration Procedure

1. With the unit fully preheated and in measurement condition, press the vibration button and the buzzer button simultaneously. The equipment will beep upon successful activation.
2. Press the BackLight button 4 times, then the APO button 4 times. The equipment will beep, and the LCD screen will no longer show numerical gas concentration, indicating entry into calibration mode. (To enter school table mode, AutoZero must be canceled).
3. Press the APO button to select the calibration gas concentration. Options include 400ppm, 0ppm, and 5000ppm. Cycle through these options with short presses of the APO key.
4. Once the desired gas concentration is selected, do not press any other button. Wait 3 seconds. The equipment will beep, and the LCD screen will display the CAL icon, entering calibration model.
5. During manual calibration, the LCD screen will display the CAL icon. The gas concentration and numerical LCD screen area will not show the calibration value. The maximum gas concentration and explosion limit indication areas will show the original measurement data. For example, max value 2, explosion limit 18, original concentration 218.
6. To calibrate for 0ppm, place the equipment in a 0ppm environment. Once the original measurement data is stable, long-press the ON/OFF button to save and write the calibration value. Short-press ON/OFF to cancel.
7. To cancel calibration or if a calibration data error occurs (e.g., 1000ppm data is less than 0ppm), the unit will exit calibration. The CAL icon will flash for 10 seconds and beep. If successful, the unit exits calibration and displays the combustible gas concentration value.
8. To exit calibration mode without saving any results, press and hold the vibration button and the buzzer button simultaneously. Release them at any time before the CAL icon disappears.

8.2.2. Restore Factory Settings

To restore factory settings, ensure the unit is fully preheated. Press and hold both the High/Low Sensitivity button and the buzzer button. The unit will beep upon successful operation. Continue holding until the RESET icon appears on the LCD screen, indicating entry into the production setting mode. To exit this mode without restoring settings, release both buttons before the RESET icon disappears.

9. Troubleshooting

10. Storage

Store the GD-3308 in a dry, secure area with temperatures between -10°C (14°F) and 60°C (158°F). Keep the tool in a locked area, out of reach of children and individuals unfamiliar with its operation. Remove the battery before any long period of storage or shipping to prevent battery leakage.

11. Disposal

Parts of the CEM GD-3308 Combustible Gas Leak Detector contain valuable materials that can be recycled. Dispose of components in compliance with all applicable regulations. Contact your local waste management authority for more information on proper recycling procedures.

12. User Tips

• The GD-3308 is capable of detecting Hydrogen, making it versatile for various gas leak detection needs.
• Always ensure the unit is fully charged before critical use to avoid interruptions.
• For best accuracy, perform the auto-zero function in a clean air environment before each use.

13. Warranty and Support

For detailed warranty information, service, and support, please refer to the official user manual PDF available for download. You can access the PDF here.