When I’m testing my BBA-2500 it isn’t alarming?

The BBA-2500 systems are not true “photoelectric sensors” they actually use infrared break beams, so to trigger the system both beams need to be broken simultaneously by something warm, such as a hand, arm etc. when testing. Some customers have been testing the units using pieces of cardboard etc. which block the beam, but will not trigger an alarm because they are not warmer than the background temperature.