1. If it is a pump-suction gas detector, first check whether the air pump is working normally, and block the air inlet with your finger for 5 seconds. If it is normal to feel obvious suction, if there is no suction, check whether the air inlet is blocked;
2. Pour in nitrogen to calibrate the zero point or calibrate the zero point in clean air, and then perform the test after calibration;
3. If no gas is detected after zero point calibration, it is necessary to restore the factory settings;
4. After all the above steps are completed, the detection cannot be detected. It is necessary to confirm whether there is a gas to be measured on site, or the concentration of the gas to be measured is really low. If it is lower than the minimum detection accuracy of the gas sensor, it cannot be detected.