yeah, scott in that case i would agree. the co detectors would activate supply, exaust and associated circulator fans. you'd wire that control circuit through a PAM relay that is tied into the fire alarm system, that way the f/a is isolated from the co control circuit. so when there is a fire the f/a system would shut down the fans. at least that's how i've done them in the past. i've also wired switches in the fire control room annunciator so the fire marshall could override the fans. enabling the fire marshall to stand in the fire control room and either shut down or turn on the fans to clear smoke from the garage.
