Three Typical Failures for Combustible Gas Detectors
Ⅰ. Improper Operation by Users
During operation of combustible gas detectors, air‑conditioners and heating equipment shall not be installed close to the detectors. If cold or hot airflow blows directly onto the combustible gas alarm, the resistivity of its platinum wire may change and produce measurement errors. Therefore, combustible gas alarms shall be kept away from air‑conditioners and heating devices to avoid faults caused by improper installation positions.
Electromagnetic interference shall also be prevented during operation. Anti‑interference measures shall be considered for installation location, mounting angle, protective measures and system wiring of combustible gas alarms. Electromagnetic interference affects the alarms mainly through three paths: airborne electromagnetic waves, narrow pulse groups on power supply and other input‑output lines, and human‑body static electricity. For instance, mounting an alarm close to an air‑conditioner may cause detection deviations. If detection cables are laid in close proximity to high‑power power cables or lighting cables without anti‑interference treatments, detection errors will also occur.
Users shall also take note of fault‑inducing factors such as dust, high temperature, high humidity and rain exposure. When exhaust fans are required on site, they shall not be placed adjacent to combustible gas detectors; otherwise leaked combustible gas cannot fully diffuse to the detector and timely detection will fail.
For detectors installed in explosive‑proof areas, explosion‑proof type combustible gas alarms shall be adopted for Class‑A workshops where combustible gas is released, and their explosion‑proof grade shall not be lower than the requirements specified in applicable codes.
Avoid locations subject to high temperature, high humidity, steam and cooking fume. Do not place or hang objects on the detector. Do not arbitrarily relocate installed combustible gas detectors. Products with replaceable sensor probes are recommended for ease of maintenance.
Ⅱ. Non‑standard Construction Practices
Non‑standard construction will trigger detection faults in subsequent service. For example, if the detector is not mounted near potential leak points or is installed next to exhaust fans, leaked gas cannot reach the sensor and hazards will not be detected promptly.
For residential premises, combustible gas detectors shall be fitted near gas pipelines and cookers in kitchens. For natural‑gas applications, mount the detector within 300 mm below the ceiling. For liquefied petroleum gas (LPG), install the detector within 300 mm above the floor.
Reliable grounding is mandatory. Without proper grounding, electromagnetic interference cannot be eliminated, which disturbs voltage signals and leads to inaccurate readings. Alarms and terminal blocks shall not be arranged in positions vulnerable to mechanical impact or water ingress, which may result in open‑circuit or short‑circuit failures.
Corrosion‑free flux must be used for soldering; otherwise joints may corrode and separate or exhibit increased circuit resistance, impairing normal detection. Detectors shall not be dropped or thrown. Commissioning shall be completed upon construction completion to guarantee normal performance of the combustible gas alarm.
Ⅲ. Maintenance and Servicing
To measure combustible‑gas concentration, the detector must communicate with ambient air. Consequently, contaminants and dust in the atmosphere inevitably enter the sensor and degrade its working conditions. Many detectors are deployed outdoors under harsh environments. Poor maintenance will cause reading drift or complete detection failure. Regular cleaning and maintenance are critical for fault prevention.
Grounding connections shall be inspected periodically. Sub‑standard or missing grounding makes the unit susceptible to electromagnetic interference and resultant malfunctions.
Attention shall be paid to component aging. Practical experience demonstrates that systems with service life exceeding 10 years suffer rising failure rates caused by component degradation. Units that have exceeded their specified service life shall be replaced in a timely manner.
