Kidde Sentry 4x KF21 Optical Smoke & 1x KF31 Heat Alarm Kit with 9V Battery Back-Up

The Kidde Sentry Alarm Kit includes four KF21 Optical Smoke Alarms and one KF31 Heat Alarm, providing a complete mains-powered fire detection solution for larger residential properties. Designed to deliver reliable smoke and heat detection throughout the home, each alarm features a 9V alkaline battery back-up and can be interconnected with up to 23 compatible Kidde FIREX alarms.

This interlinked alarm system ensures that when one alarm detects danger, all connected alarms sound simultaneously, helping to provide earlier warning and improved occupant safety across multiple rooms and floors.

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

Kit Contents

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

KF21 Optical Smoke Alarm Features

The Kidde KF21 optical smoke alarm is ideal for detecting slow, smouldering fires caused by electrical faults, furniture or cigarettes. Suitable for escape routes and living spaces, the optical sensor 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 activated alarm
• Combined Test/Hush button
• Auto reset after activation
• Tamper-resistant locking mechanism
• Suitable for hallways, bedrooms, lofts and living areas
• 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 steam, dust or cooking fumes. Its thermistor heat sensor provides reliable temperature detection while helping reduce nuisance alarms.

• Mains-powered heat alarm with 9V alkaline battery back-up
• Thermistor heat sensor for dependable 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

• Complete smoke and heat alarm solution for larger homes
• Interlinked alarms provide whole-home warning when danger is detected
• Quick-Fit bases for fast and efficient installation
• Integrated cable management for tidy wiring
• Suitable for compliance with UK Building Regulations
• Grade D domestic 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