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Mains Powered Optical Smoke Alarm with Back-Up Battery - Kidde Firex KF20

Front view of kidde firex mains powered optical smoke alarm alkaline battery backup in white with sensor and vent details
Customer Reviews

20+ In Stock

Estimated dispatch: Monday 8th June

£23.99 inc VAT

£19.99 ex VAT

Standard Delivery

Will usually be delivered in 2-3 working days

£4.20 inc VAT

Next Day Delivery

Will usually be delivered the next working day

£7.00 inc VAT

The Kidde Firex KF20 and KF20R alarms are a pair of mains powered optical smoke alarms that use up to 70% less energy than their predecessors and are capable of hardwire interlinking with up to 24 other compatible units. The KF20 is fitted with a replaceable alkaline back-up whilst the KF20R is fitted with a rechargeable lithium battery which is designed to last the life of the alarm.

  • 230V mains powered optical smoke alarm
  • Optional alkaline or rechargeable lithium back-up battery versions
  • Up to 70% less energy consumption compared to previous Firex models
  • 6 year warranty
  • A maximum of 24 units can be interlinked via signal cable
  • Kitemarked to
  • Suitable for installations complying to Grade D1 (lithium) or Grade D2 (alkaline)
  • CE marked
  • LED indicator
  • Test / Hush button
  • Low battery warning chirp – can be silenced for 8 hours
  • Supplied with dust cover (to protect unit temporarily if you carry out dusty work)
  • Supplied with fixings; 2 x screws and 2 x rawl plugs

Please Note: The Kidde Firex KF20 (previously Kidde 4973 / KF2) and KF20R (previously Kidde 4985 / KF2R) are replacements for the Kidde 2239HI and 2239HILLs and can still be interlinked, however the new models cannot be used on the same base plates and use different connector blocks.

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Technical Data

Technical Data

Product Code KEKF20
Brand Kidde
Back-Up Battery Type Alkaline
British Standard Grade Grade D2: Mains Powered (replaceable backup)
Colour White
Local Legislation Scottish Legislation (2022)
Welsh Legislation (2022)
Approvals & Markings CE Marked
Compliance BS 5839-6
BS EN 14604: 2005
Connection Wired
Display LED Indicators
Fixing Options Screws (included)
Installation Position Ceiling
Material Plastic
Maximum Number of Linked Devices 24 Devices
Operating Temperature 0°C To +40°C
Positioning Bedrooms
Hallways
Living Rooms
Power Type Mains Powered (230V)
Product Range Kidde Firex
Recyclable Yes - Valpak's WEEE Distributor Take-back Scheme
Relative Humidity Up To 93%
Sensor Type Optical
Sound Level 85dB
Suitability Home
Warning Type Audible - Alarm Sounder
Warranty 6 Years
Dimensions (Unit)
  • Height: 39mm
  • Diameter: 133mm
Weight 280g
Datasheets
Interlink

Interlink

Alarms from the Same Series

The table below shows all the units that can interlink with the Firex KF Series.

Model Number Type of Unit Type of Interlink
KF10 Ionisation Smoke Alarm Hardwire interlink
KF10R Ionisation Smoke Alarm with Rechargeable Lithium Cell Hardwire interlink
KF20 Optical Smoke Alarm Hardwire interlink
KF20R Optical Smoke Alarm with Rechargeable Lithium Cell Hardwire interlink
KF30 Heat Alarm Hardwire interlink
KF30R Heat Alarm with Rechargeable Lithium Cell Hardwire interlink
KF1 Ionisation Smoke Alarm Hardwire interlink
KF1R Ionisation Smoke Alarm with Rechargeable Lithium Cell Hardwire interlink
KF2 Optical Smoke Alarm Hardwire interlink
KF2R Optical Smoke Alarm with Rechargeable Lithium Cell Hardwire interlink
KF3 Heat Alarm Hardwire interlink
KF3R Heat Alarm with Rechargeable Lithium Cell Hardwire interlink

Carbon Monoxide Alarms

Model Number Type of Unit Type of Interlink
4MCO CO Detector with Rechargeable Lithium Cell Hardwire interlink
K4MCO CO Detector with Rechargeable Lithium Cell Hardwire interlink

Compatible Alarms

Model Number Type of Unit Type of Interlink
1239HI Ionisation Smoke Alarm with Alkaline Battery Hardwire interlink
1239HILL Ionisation Smoke Alarm with Lithium Battery Hardwire interlink
2239HI Optical Smoke Alarm with Alkaline Battery Hardwire interlink
2239HILL Optical Smoke Alarm with Lithium Battery Hardwire interlink
3239HI Heat Alarm with Alkaline Battery Hardwire interlink
3239HILL Heat Alarm with Lithium Battery Hardwire interlink
4870 Ionisation Smoke Alarm with Alkaline Battery Hardwire interlink
4881 Ionisation Smoke Alarm with Lithium Battery Hardwire interlink
4973 Optical Smoke Alarm with Alkaline Battery Hardwire interlink
4985 Optical Smoke Alarm with Lithium Battery Hardwire interlink
4899 Heat Alarm with Alkaline Battery Hardwire interlink
4892 Heat Alarm with Lithium Battery Hardwire interlink
I240C Ionisation Smoke Alarm with Alkaline Battery Hardwire interlink
PADC240 Optical Smoke Alarm with Alkaline Battery Hardwire interlink