Kidde Sentry 3x KF21R Optical Smoke & 1x KF31R Heat Alarm Kit with Rechargeable Lithium Battery Back-Up

The Kidde Sentry Alarm Kit includes three KF21R Optical Smoke Alarms and one KF31R Heat Alarm, providing reliable whole-home fire detection for residential properties. Designed for mains-powered installation, each alarm features a sealed rechargeable lithium battery back-up and can be interconnected with up to 23 compatible Kidde FIREX alarms.

This advanced fire alarm system is ideal for larger homes, delivering dependable smoke detection in hallways, bedrooms and living areas, alongside dedicated heat detection for kitchens, garages and loft spaces.

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

Kit Contents

• 3 x Kidde KF21R Optical Smoke Alarms
• 1 x Kidde KF31R Heat Alarm

KF21R Optical Smoke Alarm Features

The Kidde KF21R optical smoke alarm is designed to detect slow, smouldering fires caused by electrical faults, upholstered furniture or cigarettes. Ideal for circulation routes and living spaces, the optical sensor delivers dependable early warning protection.

• Mains-powered optical smoke alarm with sealed rechargeable lithium 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

KF31R Heat Alarm Features

The Kidde KF31R heat alarm is designed for kitchens, garages and loft spaces where smoke alarms may be unsuitable due to steam, cooking fumes or airborne dust. The thermistor heat sensor provides reliable heat detection while helping minimise nuisance alarms.

• Mains-powered heat alarm with sealed rechargeable lithium 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 including battery

Key Benefits

• Complete smoke and heat alarm solution for larger residential properties
• Sealed rechargeable lithium battery back-up for maintenance-free operation
• Interlinked alarms provide whole-home warning when danger is detected
• Quick-Fit bases for fast and efficient installation
• Integrated cable management for organised wiring
• Suitable for compliance with UK Building Regulations
• Grade D1 domestic fire alarm system solution
• Fully compatible with Kidde FIREX smoke, heat and CO alarms

Technical Specifications

KF21R Optical Smoke Alarm

• Model: KF21R
• Power Supply: 230V mains with sealed rechargeable lithium battery back-up
• Sensor Type: Optical
• Alarm Volume: 85dB minimum at 3 metres
• Dimensions: 150mm x 150mm x 53mm
• Weight: 260g
• Operating Temperature: -10°C to +40°C
• Warranty: 10 Years

KF31R Heat Alarm

• Model: KF31R
• Power Supply: 230V mains with sealed rechargeable lithium battery back-up
• Sensor Type: Thermistor heat sensor
• Alarm Volume: 85dB minimum at 3 metres
• Dimensions: 150mm x 66mm
• Weight: 245g
• Operating Temperature: -10°C to +40°C
• Warranty: 10 Years including battery

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

Downloads

KF21R Data Sheet:
Download KF21R Data Sheet

KF31R Data Sheet:
Download KF31R Data Sheet

KF21R Instruction Manual:
Download KF21R Instruction Manual

KF31R Instruction Manual:
Download KF31R Instruction Manual