Any loss or unwanted operation of alarm outputs can affect the building fire strategy
Confirm what should operate, record the affected circuits and areas, and apply the site impairment procedure where audible or visual warning coverage is reduced.
MOST LIKELY CAUSES
Start with the output and panel information
Symptom variations Match the exact circuit, device and output behaviour. ⌄
- Strobe remains dark during test
- Sounder works but beacon does not
- One VAD fails while others operate
- Panel reports output or device fault
- Fault begins after replacement or extension
Safe first checks Checks for authorised site staff before engineering work. ⌄
- Confirm whether the issue affects one device, one circuit or several areas.
- Record all panel fault, disablement and output indications.
- Check whether the expected cause-and-effect should operate the device.
- Review recent testing, alterations and building work.
- Do not leave alarm outputs isolated without formal controls.
Step 1 — Confirm the VAD is intended to operate Follow the site fire procedure and do not leave alarm outputs isolated without formal impairment controls. ⌄
Check the cause-and-effect, test group and any disablement.
Step 2 — Record the device and affected area Follow the site fire procedure and do not leave alarm outputs isolated without formal impairment controls. ⌄
Note the loop, address, circuit, category and mounting location.
Step 3 — Treat reduced visual coverage as an impairment Follow the site fire procedure and do not leave alarm outputs isolated without formal impairment controls. ⌄
This is especially important where occupants rely on visual warning.
What the indication usually means How this sounder or output condition develops. ⌄
A visual alarm device may fail because of a circuit fault, failed VAD, insufficient supply, incorrect address, disabled output or programming that does not include the device.
Engineer diagnostic sequence Competent-person checks after the site information has been captured. ⌄
- Command the VAD individually where supported.
- Check supply voltage, loop current and output loading.
- Verify device compatibility, address and flash setting.
- Inspect local wiring, base and isolator status.
- Complete a visual coverage and functional retest after repair.
Information and equipment needed Useful items for accurate fault finding. ⌄
- Panel make and model
- Cause-and-effect matrix
- Sounder and VAD circuit schedule
- As-fitted drawings and zone plan
- Manufacturer test tools and calibrated sound-level equipment where required
Parts that may be involved Components commonly associated with this fault. ⌄
- Compatible VAD or sounder beacon
- Device base
- Output module
- Power-supply unit
- Loop or alarm circuit cable
When immediate action is required Conditions that should trigger escalation or an impairment plan. ⌄
- A complete sounder or VAD circuit is unavailable.
- Sleeping accommodation or high-noise areas may not receive warning.
- Visual alarm coverage relied upon by occupants is lost.
- Sounders activate without a confirmed fire condition.
- The output fault affects multiple panels or networked areas.
- The system cannot be returned to normal after testing.
Frequently asked questions Common sounder and output questions. ⌄
Can a quiet alarm be judged by listening?
Listening is useful for identifying an obvious problem, but proper audibility assessment requires controlled testing and suitable measuring equipment.
Can one failed sounder be left until the next service?
Not automatically. The Responsible Person should assess the affected coverage and arrange prompt repair or temporary measures.
Why would a sounder work during one test but not another?
Different tests may use different output groups, cause-and-effect rules or control states.