The Marantec ATC-100 Timer-to-Close Module is an add-on accessory that enables automatic closing of a garage door after a set delay on compatible Marantec operators. Identified by part number 105708 (updated to 120885), this module functions as a timer-to-close (TTC) upgrade or replacement part, ideal for residential or light commercial applications where a door should close automatically after being left open. Once installed on the opener’s control board accessory port, the ATC-100 provides a selectable delay so the door will close after the programmed interval. The auto-close function is commonly used to enhance convenience and help maintain security in high-traffic or shared-access garages.
For safety and compliance, a working, monitored photoelectric sensor system is required to use timer-to-close features in accordance with UL 325. Installation and programming steps vary by operator; on most Marantec garage door openers the module plugs into the logic board and the close-delay is configured through the opener’s menu or the module’s supported settings as directed in the product or operator manual. This timer-to-close module is not universal; verify compatibility with your specific Marantec opener model and documentation before purchase or installation. Common search terms include Marantec ATC-100, timer-to-close module 105708/120885, auto-close accessory, garage door opener upgrade, and replacement timer for Marantec residential/commercial operators.