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. ⌄
- One device silent during test
- Nearby sounders operate
- No obvious panel fault
- Sounder replaced recently
- Device LED or isolator indication abnormal
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 device should 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 local disablement.
Step 2 — Record the exact location and device details Follow the site fire procedure and do not leave alarm outputs isolated without formal impairment controls. ⌄
Note the loop, address, circuit and sounder type.
Step 3 — Inspect without disturbing protection unnecessarily Follow the site fire procedure and do not leave alarm outputs isolated without formal impairment controls. ⌄
Check the device is present, secure and visibly undamaged.
What the indication usually means How this sounder or output condition develops. ⌄
When one sounder fails but others operate, the most likely causes are a failed device, poor local connection, incorrect address, sounder-base fault or a local programming omission.
Engineer diagnostic sequence Competent-person checks after the site information has been captured. ⌄
- Command the device individually where the panel supports it.
- Check local supply, loop communication and base contacts.
- Verify address and output-group assignment.
- Substitute a compatible known-good device where authorised.
- Retest the device and surrounding area 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 sounder
- Sounder base
- Address programmer
- Local loop or circuit cable
- Short-circuit isolator
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.