Kidde Sentry 2x KF21R Optical Smoke & 1x KF31R Heat Alarm Kit with Rechargeable Lithium Battery Back-Up

The Kidde Sentry Alarm Kit combines two KF21R Optical Smoke Alarms and one KF31R Heat Alarm to provide dependable 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 alarm system delivers reliable smoke and heat detection across hallways, bedrooms, living spaces, kitchens and loft areas, helping properties comply with UK Building Regulations while enhancing occupant safety.

Each alarm is supplied with Kidde’s Quick-Fit Slide-On Base for faster installation, while integrated cable management ensures neat and secure wiring. The 150mm flared base plate also provides a clean finish during retrofit installations.

Kit Contents

• 2 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, furniture or cigarettes. Ideal for escape routes and living areas, the optical sensor provides 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 cooking fumes, dust or steam. The thermistor heat sensor provides reliable heat detection while reducing 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 system for residential properties
• Sealed rechargeable lithium battery back-up for maintenance-free protection
• Interlinked alarms provide whole-home warning when danger is detected
• Quick-Fit bases for fast and efficient installation
• Integrated cable management for neat 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 carried out 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