Thanks You…..I was doing exactly what you suggested but would not clear. Found that my issue was that I had both 2 wired and 4 wired active on the main controller. 2 wired was still on 16 with jumper J1 in the smoke position for that zone. I had added 4 wire smokes on zones one, two etc…..power from SAUX but forgot to remove the zone 16 2 wire smoke and set the jumper J1 to normal. Once i did that the issue cleared. Maybe there should be a warning in the manual saying that having both two and four wired smokes on the same controller (zone 16 J1 in smoke and adding a four wire to another zone) are not compatible.