Extruders must maintain a stable temperature for TEMP_RESIDENCY_TIME before M109 will return success and start the print. Tune what "stable" means using TEMP_HYSTERESIS and TEMP_WINDOW.
For a variety of models, shop for Intermatic pool timer parts like switch mechanisms, motors, and more!#73 - Go to the Lightning Pool10-09-2019. #72 - The Talent for Making Dan10-02-2019.