With built-in Degraded Manner operation, the method is effective at normal alarm if a fireplace alarm situation is existing whether or not the central processing unit (CPU) fails The 302-AW-one hundred thirty five Thermotech fee-anticipation warmth detector from Honeywell NOTIFIER operates within a controlled variety of two to 3 levels https://www.firesense.co.uk/type/addressable-fire-system/addressable-beam-detectors/