Kidde Sentry 5x KF21 Optical Smoke & 1x KF31 Heat Alarm Kit with 9V Battery Back-Up

The Kidde Sentry Alarm Kit combines five KF21 Optical Smoke Alarms and one KF31 Heat Alarm to provide complete fire detection coverage for larger homes and multi-storey residential properties. Designed for mains-powered installation, each alarm features a 9V alkaline battery back-up and can be interconnected with up to 23 compatible Kidde FIREX alarms for dependable whole-home protection.

When one alarm detects danger, all connected alarms sound simultaneously, providing an early warning throughout the property. This makes the system ideal for improving fire safety across multiple rooms, floors and escape routes.

Each alarm is supplied with Kidde’s Quick-Fit Slide-On Base for fast and tidy installation. Integrated cable management helps maintain organised wiring, while the 150mm flared base plate provides a neat finish when retrofitting existing alarms.

Kit Contents

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

KF21 Optical Smoke Alarm Features

The Kidde KF21 optical smoke alarm is designed to detect slow, smouldering fires caused by furniture, electrical faults or cigarettes. Ideal for hallways, landings, bedrooms and living areas, the optical sensor provides reliable early fire detection.

• 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 activated alarm
• 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 designed for kitchens, garages and loft spaces where smoke alarms may be unsuitable due to cooking fumes, steam or dust. The thermistor heat sensor provides dependable heat detection while reducing 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 activated alarm
• Combined Test/Hush button
• Auto reset after activation
• Tamper-resistant locking mechanism
• Ideal for kitchens, garages and loft spaces
• BSI certified to BS 5446 Part 2:2003
• 10-year warranty

Key Benefits

• Comprehensive smoke and heat alarm system for larger homes
• Interlinked alarms provide whole-property warning when danger is detected
• Quick-Fit bases for fast and clean installation
• Integrated cable management for neat wiring
• Suitable for compliance with UK Building Regulations
• Grade D domestic fire alarm 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