Kidde Firex Sentry Mains Powered Optical Smoke Alarm with 9V Backup Battery (KF21)
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Product Details for Kidde Firex Sentry Mains Powered Optical Smoke Alarm with 9V Backup Battery (KF21)
The Kidde KF21 (Firex Sentry series) is a mains-powered Grade D2 optical smoke alarm with a 9V alkaline battery backup, engineered to provide early warning of slow, smouldering fires in residential properties.
Certified to BS EN 14604:2005, the unit features an advanced optical sensor equipped with a bug screen and automatic dust compensation to maintain stability and minimise false alarms caused by airborne particulates.
Designed for straightforward installation and retrofitting, the KF21 includes a Quick-Fit slide-on base with integrated cable management and a 150mm flared mounting plate that covers existing footprint marks. The alarm supports hardwired interlinking with up to 24 compatible Kidde and Firex smoke, heat, and CO devices.
System operation is managed via a central Test/Hush button, complemented by a built-in alarm memory function, automatic reset, tamper-resistant base locking mechanism, and mini-trunking knockouts. Housed in a flame-retardant enclosure (150mm x 53mm), the alarm includes an 85dB sounder at 3 metres and is backed by a 10-year manufacturer warranty.
Key Features of the KF21 |
|---|
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> Slide‑on Quick‑Fit base aligns with common back‑box spacing to reduce re‑drilling
> Flared base plate helps cover fixing marks from previous alarms for a cleaner finish > Interlinks with up to 23 other Kidde FIREX alarms (smoke, heat and CO) – all sound when danger is detected > Integrated cable management keeps wiring secure and organised across multi-unit housing jobs > Alarm memory identifies the source unit – find the source instantly across any interconnected system |
| Brand | Kidde Safety Europe |
|---|---|
| Manufacturer Part No. | KF21 |
| Warranty | 10 Years |
| Colour | White |
| Interlink Options | Hard-wire Interlink Only |
| Detectable Medium | Smoke |
| Sensor Type | Optical |
| Primary Power Source | Mains Powered (230V) |
| British Standard Grade (BS5839-6) | Grade D2 (Mains Powered with Replaceable Back-up Battery) |
| Approvals | BSi Kitemark |
| Regional Compliances | 2022 Scottish Legislation Compliant, 2022 Welsh Legislation Compliant |
FAQ’s for Kidde Firex Sentry Mains Powered Optical Smoke Alarm with 9V Backup Battery (KF21)
Product Specification for Kidde Firex Sentry Mains Powered Optical Smoke Alarm with 9V Backup Battery (KF21)
| Model |
KF21
|
| Power Source |
230V mains-powered with 9V alkaline battery back-up
|
| Sensors |
Optical, with dust compensation and insect screen to reduce nuisance alarms
|
| Audio Alarm |
85dB (A) minimum at 3 metres Alarm Frequency 3.2 kHz typical
|
| Approvals / Certification |
BSI certified · BS EN14604:2005+AC:2008 · UKCA · CE
|
| Dimensions |
Ø150 mm × 53 mm (including base) |
| Weight |
295g including batteries
|
| Temperature Range |
-10ºC to + 40ºC
|
| Storage and Transport |
-20ºC to +60ºC and 5–95% relative humidity (RH) non-condensing
|
| Humidity Range |
Up to 93% Relative Humidity (RH) non-condensing
|
| Warranty |
10 years
|
