Carbon Monoxide Alarm

1 Year Replaceable Batteries

Looking for a CO-9B alarm replacement? With the latest sensing technology, a clear loud alarm and BSI Kitemark approval, the FA3313X4 offers the highest level of CO detection for your home and replaces end-of-life CO-9B alarms.


Third party tested and approved.

5 Year Warranty

For peace of mind.




To ensure you install the right alarm for your home, and one that's compliant with your local carbon monoxide regulations, review our manual and data sheet or get in touch with our customer service team.


Installation Support and Guidance


Specification Detail and Standards




The FA3313X4 alarm cannot be interlinked to other alarms in your home, but still offers the highest protection. Follow the installation guides to ensure this alarm is fitted correctly.

Testing Support

Testing and maintenance support.

Enhanced CO sensing Fast reaction to rising CO levels

Intelligent CO sensing technology enables the alarm's high sensitivity mode to be activated if it predicts CO levels will increase to or above 180ppm for a quicker alert.

Fast reaction to rising CO levels
Battery powered protection 1 year batteries included

The alarm comes with 2 x AA batteries that can be replaced once you hear the low battery chirp to keep you protected. For a decade of protection look for our range for FireAngel Pro Connected alarms.

1 year batteries included
Sleep Easy Enjoy a peaceful night's sleep

Give yourself vital time to replace your alarm, by silencing low battery warnings for 8 hours.

Enjoy a peaceful night's sleep

Did you know?

Alarm memory indicates previous activation Discover more

With the alarm memory function, a red LED will flash to let you know with a visual indication that there has been a previous CO alarm activation within the last 30 days.

Discover more
Complete the range…


Yes – this Carbon Monoxide Alarm is suitable for all domestic settings, including caravan holiday homes, caravans, motor caravans and boats.

A Carbon Monoxide alarm is the only way to receive an audible alert to the presence of Carbon Monoxide (CO) in your home, or whilst you’re away on holiday.

CO is a gas which cannot be seen, tasted or smelt but can result in CO poisoning and illness or in some cases death. It’s created in our homes when the fuel in products, such as boilers, fires and ovens does not burn completely. Regular servicing of these products can reduce the risk of CO being present but it cannot completely remove the risk.

Yes – Our FP1820W2-R, FA3820X4 and FA3322X4 products have sealed for life batteries and will protect your home, without you need to replace the batteries every year.

Carbon Monoxide is produced when fuels burn incompletely – this could be from a boiler, gas fire, oven, log burner or a blocked flue or chimney. It can also travel through walls from adjoining properties, so as well as having an alarm next to appliances in your property we would also advise you have one in living spaces and bedrooms.

To help prevent a Carbon Monoxide leak we advise getting your appliances regularly serviced by reputable engineers who are gas safety registered.

When a Carbon Monoxide alarm is triggered, it will emit an alarm sound consisting of 4 loud beeps and a break repeated until the sensor is clear of Carbon Monoxide gas.

Yes – the FireAngel Pro Connected FP1820W2-R Carbon Monoxide Alarm, when paired with a Smart Gateway, will allow you to review alerts and easily test the alarm from your phone.

The common sources of Carbon Monoxide (CO) are cookers, fires, boilers, oil and gas boilers, portable generators, oil or solid fuel cookers, gas or paraffin heaters, barbecues (BBQs), clogged chimneys, wood or gas fireplaces, cigarette smoke or any fossil fuel-burning appliances.

Regular servicing of these items will help reduce the risk of CO in your home but it will not completely remove the risk. The only way to detect CO in your home is to install a Carbon Monoxide detector with an audible alarm.

Yes – this carbon monoxide alarm is suitable for all domestic settings, including caravan holiday homes, caravans, motor caravans and boats.

From October 1st 2022, the law is changing surrounding carbon monoxide alarms in rented properties – for both the private and social sectors.

Your landlord will need to ensure as a tenant you have a working carbon monoxide alarm 1-3 metres away from any fuel burning appliances in a room (excluding gas cookers) and that any faults or repairs are carried out on the alarm in a timely manner. For more information, read this blog.

Guidance for where to install your smoke, heat and CO alarms can be found below:

Why is my FireAngel smoke alarm beeping?

Where your alarm is installed can trigger nuisance alarms if not correctly placed, for example too close to doors or windows.

Why is my FireAngel smoke alarm beeping?

For more guidance as to where to install your smoke, heat or CO alarm please refer to your alarm’s manual or contact our friendly Customer Support team.