If there was a fire and your 12 year old son was at the alarm and tried pulling the handle and it did not go down and asked for an extra hand to pull it together how would you respond? What if he asked you why the handle was not going down? If the handle only went half way down when the son tried but it went back up what would you think happened? Would you pull it down together in case it was a bit stuck? If your son said I will pull a second alarm just to be sure the first one worked how would you respond?
The sensing electronic element inside the fire alarm mechanism could probably be defective. You need to dismantle the alarms and have it checked for proper adjustments. You can check the proper settings of the non defective alarm and use this setting to fix the defective ones.
Try and OKorder. Those are likely places.
