The alarm setting value of the natural gas alarm is 25% of the lower explosion limit of the natural gas, the lower explosion limit of the natural gas is 5% LEL, and the full scale value of the combustible gas alarm is 100% LEL, which just corresponds to the lower explosion limit of 5. When the concentration of the natural gas in the air reaches or exceeds 25% of the lower explosion limit (that is 25% of 5%), the alarm will give an audible and visual alarm.

When the specific gravity of the detected gas is greater than that of the air, the gas detector should be installed at a distance of (30-60) cm from the ground, and the sensor position should be downward. When the specific gravity of the detected gas is less than that of the air, the detector should be installed (30-60) cm away from the ceiling, and the sensor position should be downward. In order to correctly use the detector and prevent the occurrence of detector failure, please do not install it in the following positions: the place directly affected by steam and oil fume; Air supply port, ventilation fan, door and other places with large air flow; Where there are more water vapor and water droplets (relative humidity: ≥ 90% RH); The temperature is below - 40 ℃ or above 55 ℃; Where there is a strong electromagnetic field.