Kidde Sentry KF21 & KF31 Mains Powered Smoke and Heat Alarm Kit with 9V Battery Back-Up

The Kidde Sentry Alarm Kit combines the reliable KF21 Optical Smoke Alarm and KF31 Heat Alarm to provide comprehensive fire detection throughout residential properties. Designed for mains-powered installation, both alarms feature 9V alkaline battery back-up protection and can be interconnected with up to 23 compatible Kidde FIREX alarms for complete home safety coverage.

This convenient alarm combination is ideal for meeting UK Building Regulations in domestic properties, offering dependable smoke and heat detection across living spaces, hallways, kitchens, garages and loft areas.

Each alarm is supplied with Kidde’s Quick-Fit Slide-On Base for faster installation, while integrated cable management keeps wiring neat and secure. The 150mm flared base also provides a tidy finish when replacing existing alarms.

Kit Contents

• 1 x Kidde KF21 Optical Smoke Alarm
• 1 x Kidde KF31 Heat Alarm

KF21 Optical Smoke Alarm Features

The Kidde KF21 optical smoke alarm is designed to detect slow, smouldering fires commonly caused by furniture, electrical faults and cigarettes. Ideal for escape routes and living areas, the alarm provides dependable early warning protection.

• Mains-powered optical smoke alarm with 9V alkaline battery back-up
• Optical sensor with dust compensation and bug screen
• Interconnects with up to 23 Kidde FIREX alarms
• Alarm memory identifies the triggered unit
• Combined Test/Hush button
• Auto reset after activation
• Tamper-resistant locking mechanism
• Suitable for hallways, bedrooms, lofts and living rooms
• BSI certified to BS EN14604:2005
• 10-year warranty

KF31 Heat Alarm Features

The Kidde KF31 heat alarm is ideal for kitchens, garages and loft spaces where smoke alarms may be affected by steam, cooking fumes or dust. The thermistor heat sensor provides reliable temperature detection without nuisance alarms.

• Mains-powered heat alarm with 9V alkaline battery back-up
• Thermistor heat sensor for reliable heat detection
• Interconnects with up to 23 Kidde FIREX alarms
• Alarm memory identifies the triggered unit
• Combined Test/Hush button
• Auto reset after activation
• Tamper-resistant locking mechanism
• Ideal for kitchens, garages and humid environments
• BSI certified to BS 5446 Part 2:2003
• 10-year warranty

Key Benefits

• Complete smoke and heat detection solution for residential properties
• Interlinked alarms provide whole-home warning when danger is detected
• Quick-Fit bases for fast and clean installation
• Integrated cable management for tidy wiring
• Suitable for compliance with UK Building Regulations
• Grade D fire alarm system solution
• Fully compatible with Kidde FIREX smoke, heat and CO alarms

Technical Specifications

KF21 Optical Smoke Alarm

• Model: KF21
• Power Supply: 230V mains with 9V alkaline battery back-up
• Sensor Type: Optical
• Alarm Volume: 85dB minimum at 3 metres
• Dimensions: 150mm x 53mm
• Weight: 295g
• Operating Temperature: -10°C to +40°C
• Warranty: 10 Years

KF31 Heat Alarm

• Model: KF31
• Power Supply: 230V mains with 9V alkaline battery back-up
• Sensor Type: Thermistor heat sensor
• Alarm Volume: 85dB minimum at 3 metres
• Dimensions: 150mm x 150mm x 66mm
• Weight: 281g
• Operating Temperature: -10°C to +40°C
• Warranty: 10 Years

Please Note: Alarms are supplied individually within the kit. Installation should be completed by a qualified electrician.

Downloads

KF21 Data Sheet:
Download KF21 Data Sheet

KF31 Data Sheet:
Download KF31 Data Sheet

KF21 Instruction Manual:
Download KF21 Instruction Manual

KF31 Instruction Manual:
Download KF31 Instruction Manual