FireAngel FAQ's

Read More About the Most Common Questions We Get Asked About Our Products and Fire Safety

Looking for a FireAngel ST-622 smoke alarm replacement?

Replace your end of life ST-622 alarm with a FireAngel FA6615-R Optical Smoke Alarm with 5 year replaceable batteries or FireAngel FA6620-R Optical Smoke Alarm with 10 year sealed for life battery, without requiring a new base plate or leaving unsightly holes in your ceiling.

In brief – Smoke Alarms will alarm when smoke is detected by the sensors within the unit whereas Heat Alarms will alarm when they detect a rapid rise in temperature in the atmosphere around the device. Heat Alarms have been specifically designed for areas with fumes and high humidity e.g. kitchens where cooking fumes are present and attics or garages where there is lots of dust and usually high humidity.

Nearly 50% of fires start in kitchens in domestic properties – installing a heat alarm in this room will mean you’re rapidly alerted to danger.


No – for Carbon Monoxide detection you need to also install a CO detector which you will find here, or a combination smoke and CO alarm – FireAngel SCB10.

No – the ST-620 has not been designed to be installed in a kitchen as it will react to cooking fumes. For fire detection in your kitchen fit a FireAngel Heat Alarm.

Yes – you can hardwire interlink this alarm with other SW1 smoke alarms and HW1 heat alarms to offer protection across the home (12 devices in total).

Yes – you can hardwire interlink this alarm with other ST-230 smoke alarms and HT-230 heat alarms to offer protection across the home (12 devices in total).

The ST-620, ST-622 and ST-750 range of alarms will all fit onto the same base plate.

A crackling alarm is a sign that there has been moisture within the unit that may have caused a corrosion build up. A crackling alarm will still function correctly and alert you to smoke providing it is testing correctly. We advise to test alarms weekly. If you are experiencing issues with a crackling alarm, our Customer Support Team will be happy to help, you can reach them here.

The internal power pack of the alarm will not activate until the unit has been correctly installed onto its base plate.

You can find out more information on why FireAngel have moved away from Ionisation alarms here –