What causes a gas detector to alarm immediately upon startup?
1, Environmental factors: actual gas exceeding the standard
Real gas leakage: Before starting up, there may have been a leakage of flammable or toxic gases in the working environment, and the concentration has reached the alarm threshold. For example, minor leaks in gas pipelines, volatilization of chemical containers, etc. In this situation, the alarm is correct and immediate action must be taken according to the emergency plan, such as evacuating personnel, cutting off gas sources, and strengthening ventilation.
High background gas concentration: Improper installation of the detector may also lead to false alarms. For example, installing the detector in areas with a long-term low concentration gas background (such as valve joints with trace and continuous leaks), or in corners with low terrain and poor air circulation (for gases heavier than air), where the gas concentration may already be close to or exceed the alarm set value.
2, Problems with the instrument itself:
Sensor malfunction or aging: The sensor is the core component of the detector and has its service life. When the sensor approaches or exceeds its service life, its performance will sharply decline, which may result in zero drift (i.e. readings that are not zero in clean air), abnormal sensitivity, and other issues, leading to false alarms as soon as it is turned on. This is the most typical cause of hardware failure.
Calibration failure or drift: All gas detectors require regular calibration to ensure the accuracy of their readings. If not calibrated for a long time, the measurement benchmark of the instrument may drift, which may mistake normal air for excessive gas. Especially when the standard gas used for calibration is impure or the calibration operation is not standardized, it is more likely to cause such problems.
Power on self-test program trigger: Some high-end or specifically designed detectors will perform a complete functional self-test upon startup, including testing the alarm circuit. During this process, it will actively trigger sound and light alarms to confirm that the alarm system is working properly. This type of alarm usually has a fixed pattern and time (such as automatically stopping after a continuous beep for 10 seconds), accompanied by specific screen prompts, and is a normal phenomenon, not a fault.
Internal circuit or program failure: Malfunctions in the instrument's motherboard, power supply, or other electronic components may also cause the program to malfunction and issue incorrect alarm commands. This situation is relatively rare, but it cannot be completely ruled out.
3, Improper operation and maintenance:
Not turning on in clean air: This is a crucial but easily overlooked point. The correct operating procedure is to turn on the instrument in a confirmed clean air environment and complete the "zero point setting". If the instrument is turned on in an environment where there are already trace amounts of polluted gases, it will mistake this pollution state for the zero point of "clean air". When there is a slight change in the environment later, it will immediately sound an alarm.
Sensor poisoning or contamination: If the detector has been exposed to high concentrations of "inhibitor" gases (such as silicides, sulfides, etc.), it may cause sensor "poisoning" and permanent damage. In addition, pollutants such as dust, oil, and water vapor covering the surface of the sensor can also affect its normal operation, leading to inaccurate readings and false alarms.
