Door coordinators are used to control the closing sequence of a pair of doors when both leaves are furnished with latching hardware and one leaf latches into the other of has an overlapping astragal. Typically, these openings will have a vertical rod exit device or automatic flush bolts installed on the inactive leaf of the opening and a mortise, bored of preassembled lock or latch or mortise exit device on the active leaf. If the active leaf closes first, the projected latch-bolt will prevent the inactive door from being able to close. In these cases, the inactive leaf must close before the active leaf, ensuring the opening returns to the closed and latched position.
