A door stuck open is a security problem, so this is one of our most common after-hours calls. The good news is that the top three causes account for most of them and two are things you can check yourself in five minutes.
1. Misaligned or dirty photo-eye sensors
By far the most common. The two small sensors either side of the opening must see each other. A bumped bracket, a cobweb, a bicycle leaning against one, or direct low sunlight can all break the beam. Wipe both lenses and adjust until both indicator lights are steady.
2. Something in the door's path
The door will refuse to close for a bin bag, a hose, a frozen ridge of ice or a raised floor edge. Look along the full width of the opening.
3. Close-force or down-limit set wrong
If the down-limit is set below floor level, the opener senses resistance and reverses. Both are adjustable screws on the motor housing.
4. The lock or manual latch is engaged
Easy to miss, especially on older doors that still have a side latch.
5. Damaged or obstructed tracks
A dent, a bent section or a loose bracket will stop the door partway. Do not force it. See off-track and track repair.
6. Broken or slack cables
If one cable has slipped its drum, the door goes crooked and jams. Stop using the opener immediately.
7. A broken spring
Less common for a door refusing to close than one refusing to open, but a failing spring throws the balance and confuses the opener. See spring repair.
8. Remote or wall-button fault
A stuck wall button holds the opener in a state where it will not accept a close command. Unplug the opener for a minute and try again.
9. Logic board failure
Least common, most annoying. Power surges take these out, which in Maryland means storm season. Covered under opener repair.
If the door is stuck open tonight
Pull the emergency release cord, lower the door by hand, and if it will not stay down, do not leave it half open. Call us. We answer emergency calls at any hour and securing the opening is the first thing we do.