Troubleshooting Guide for Combustible Gas Alarms
I. Basic Principles of Troubleshooting
Before performing any troubleshooting, please adhere to the following safety principles:
- Disconnect power before operating : When inspecting wiring or replacing fuses, always disconnect the power supply first.
- No open flame testing : It is strictly forbidden to test the alarm directly with a lighter. This is not only dangerous but may also damage the sensor.
- Professional handling : For complex issues involving internal circuitry or sensor replacement, it is recommended that these be handled by a qualified professional.、
II. Common Fault Phenomena and Troubleshooting Methods
Fault 1: Power indicator light is off / Device does not respond
| Possible reasons | processing method |
| No power input or power switch not turned on | Check that the power plug is properly inserted and confirm that the circuit breaker is switched on. |
| Poor contact in the power supply line | Re-crimp the power cord to ensure a secure connection. |
| Fuse or fuse blows | After power is off, check the fuses. Once the circuit is confirmed to be normal, replace the fuse with one of the same specifications. |
| Controller signal abnormal | The controller output voltage should meet the requirements specified in the instruction manual when measured with a multimeter. |
| Damage to the equipment itself | Contact the dealer to replace the faulty device. |
Operation Tips : If the mains power is out for more than 8 hours, it is recommended to turn off the mains power and turn the device back on after the mains power is restored.
Fault 2: Fault light remains on (yellow/red light)
| Possible reasons | processing method |
| The equipment has detached from the base or is making poor contact. | Re-tighten the installation to ensure good contact between the detector and the base. |
| Poor contact between the bus and the device base | When re-crimping the bus, multi-strand wires should be tinned or crimped with wire lugs. |
| Bus open circuit, grounding, or short circuit | Locate the fault in the line and troubleshoot the problem. |
| Sensor malfunction or failure | The sensor may have reached the end of its service life and needs to be replaced by contacting the dealer. |
| Motherboard/Daughter Card Failure | Professional technicians are required to inspect the card; the sub-card may need to be replaced if necessary. |
Regarding sensor lifespan :
- The service life of Combustible Gas Detectors in industrial sites is3 years.
- The service life of residential buildings is 5 years.
- It should be scrapped and replaced after its service life.
Regarding sensor expiration reminders : Some devices are designed with expiration reminders based on the sensor's lifespan (calculated from the factory date). When the lifespan is about to expire, the device will automatically alarm to prompt for replacement.
Fault 3: Unable to register for online (bus system)
| Possible reasons | processing method |
| Host circuit output abnormality | Use a multimeter to measure the circuit output voltage (there should be a jump in voltage). If there is no jump, the problem may be with the motherboard or the daughter card. |
| Incorrect encoding settings | Check if the detector encoding is correct, and re-encode if necessary. |
| Detector batch compatibility issues | Some older batches of detectors require a specific encoding protocol; please consult the manufacturer's technical support. |
Special Note : When using the 6481 "Combustible Gas Detector" protocol encoding, some older batches of Qingniao Fire Protection 5101 detectors may show success but are not actually written. It is necessary to use "Other Protocol" encoding instead.
Fault 4: No alarm when gas is introduced
| Possible reasons | processing method |
| The preheating process is not yet complete. | Wait for the warm-up to complete (usually 1-10 minutes). Some sensors need time to stabilize immediately after power-on. |
| Insufficient test gas concentration | The test should be conducted using a standard gas that meets the required specifications, and the concentration must reach the alarm set value. |
| The gas dissipated too quickly | Ensure a continuous and stable air supply during testing, and avoid testing at ventilation openings. |
| Improper alarm threshold settings | Check if the alarm threshold settings are correct, and adjust them if necessary. |
| Sensor aging failure | The sensor has reached the end of its lifespan and the gas-sensitive element needs to be replaced. |
Important notes regarding the test gas :
Many users are accustomed to using lighter gas to test whether an alarm is working properly, but in reality, the concentration of flammable gas in lighter gas is very low, often failing to meet the alarm concentration requirements. It is recommended to use a standard concentration sample gas for testing.
Fault 5: Frequent false alarms
| Possible reasons | processing method |
| On-site electromagnetic interference | Keep away from high-power motors, frequency converters, and other sources of interference, or install shielding. |
| Improper installation location | Avoid areas with ventilation openings, heavy cooking fumes, or high humidity. |
| Sensor poisoning | Avoid use in environments containing silicon, sulfur, lead, etc. Replace the sensor if poisoning occurs. |
| Data fluctuates significantly | Check for interfering gases or whether the sensor is damaged or malfunctioning. |
Regarding sensor poisoning : Catalytic combustion sensors are extremely sensitive to substances such as silicon, sulfur, and lead. Silicone, paint volatiles, etc., produced during the renovation process can cause sensor poisoning and failure.
III. Troubleshooting Main Power/Backup Power Faults
Main power failure
| Phenomenon | Investigation steps |
| Main power fault light on | 1. Check if the main power switch is on. |
backup power failure
| Phenomenon | Investigation steps |
| Backup power fault light on | 1. Check if the battery wiring is making good contact; you can solder it with a soldering iron. |
IV. Regular Maintenance Recommendations
To reduce the occurrence of malfunctions, it is recommended to perform maintenance according to the following schedule:
| Maintenance items | cycle | content |
| Indicator light/display check | per month | The display is confirmed to be normal, and the audio components are intact. |
| External line inspection | per month | The terminals are not loose and the wire markings are clear. |
| Controller function check | Quarterly | Self-test, alarm, mute, reset functions, etc. |
| Output voltage measurement | Quarterly | When measured with a multimeter, the readings should conform to the specifications in the instruction manual. |
| Alarm function test | Every six months | Use standard gas test alarm function |
| Detector calibration | Annually (industrial sites) | It can only be used after re-inspection and passing the test. |
V. Summary
| Fault phenomenon | Priority investigation items | Final processing |
| No display/No response | Power supply, fuse, wiring | Replace power board/return to factory |
| The fault light stays on. | Poor contact, wiring problem | Replace sensor/master card |
| Unable to log in | Encoding settings, loop voltage | Re-encode/replace daughter card |
| No police report | Preheating time, test gas | Replace sensor |
| Frequent false alarms | Installation location, electromagnetic interference | Replace sensor |
A simple rule of thumb : First check the power supply and wiring, then measure the gas concentration, remember the sensor's lifespan, and don't be careless with regular maintenance.
