How we fix a door that opens but won't close

A door that opens fine but refuses to close is almost always a safety system issue. Here's the sequence our technicians run.

1. 1
   Clean and realign the photo eyes. We wipe the sensor lenses and adjust them until both indicator lights hold solid — the single most common fix.
2. 2
   Clear the door's path. Any object crossing the invisible beam between the sensors stops the door from closing.
3. 3
   Inspect tracks and rollers. We check for bent track, loose hardware, and grime, then clean the tracks dry — never heavy grease, which attracts dirt.
4. 4
   Adjust the down-travel limit. If the door bounces back up on contact, the down limit needs a quarter-turn at a time until it seals.
5. 5
   Re-engage the trolley. If the emergency release cord was pulled, the motor runs but the door won't move — we reconnect it.
6. 6
   Read the diagnostic lights. We decode the motor's flash codes to pinpoint a wiring or logic-board fault.