This is how i wire in the Air Product and Controls Smoke Detector M/N: SL-2000-N on commercial HVAC equipment. I show how i wire it up and do the magnet test to make sure it kills power to the unit when tripped. On this particular Trane Gas Package unit I hooked it up to the EStop on the control terminal. This smoke detector is very versatile and can be wired up multiple different ways so make sure you use it in the correct application.