Why a garage door won't close
Closing is the moment a door can come down on a child, a pet or a car bonnet, so openers are built to be fussy about it. B&D says its safety beams pick up objects or people in the door's path and stop it closing, and its openers turn the door around if it touches something on the way down.
That changes the question. Before asking what has broken, ask what the opener believes is in the doorway. Merlin's 2019 myQ FAQ describes how that looks on its myQ openers: once the beams detect something, the door will open but not close until it has been moved.
Check the safety beams first
Clear the doorway
Look along the floor between the two beam units for a bin, a ball, a hose or a broom that has slipped over. The beam sits low, 100mm above the ground on B&D's Smart Pro, so small things can block it.
Wipe both lenses
Gliderol's troubleshooting page lists dirty or misaligned sensors among the things to check when a door won't open or close. Wipe dust and cobwebs off the face of each unit.
Read the little lights
Merlin's MR855EVO manual says a flashing red light on a beam means it is out of line, and to realign both until their lights glow steadily without flickering. Other makers signal this their own way, so check your beam's manual.
Think about the sun
Gliderol lists sun glare on the sensors among the causes of a door that starts down and then reverses. If the fault comes and goes with the time of day, low sun on a beam is worth suspecting.
Remember wireless beams have batteries
B&D's Smart Pro manual says 4 flashes of the main light after a run mean the wireless beam battery is low, and B&D says a low safety beam battery can also set the opener beeping.
What the lights can mean when it won't close
| What you see | What the maker's manual says | |
|---|---|---|
| B&D Smart Pro | 2 flashes after a run | A safety beam is stopping the door |
| B&D Smart Pro | 8 flashes | The door hit an obstruction |
| Merlin MR855EVO | The door reverses and the lights flash 10 times | Check the obstruction detection beams |
| Merlin MR855EVO | LEDs 1 and 3 on the panel flash code 1 then 4 | The safety sensors are out of line or were blocked for a moment |
| Merlin MT3850EVO | 1 flash then 1, 2 or 4 on the arrows | It will not close because of a safety beam problem |
| Merlin myQ openers (2019 FAQ) | The light flashes 10 times and the app shows CLOSE ERROR | The beams have detected an object |
Garage door starts to close, then goes back up
If the beams are clear and the door still turns around part way down, it is probably feeling resistance. Gliderol names obstructions in the tracks and the opener's force settings as causes, as well as the sensors.
Grime in the tracks is a common one. Steel-Line's sectional door manual says a door that reverses during closing and goes back to open can be a sign its tracks and hinges need cleaning, and it singles out brick dust from building work.
B&D's guide to a squeaky door says to disengage the opener before any cleaning, so wait until the door is fully down: Merlin and Chamberlain both warn against releasing an open door. B&D's Smart Pro manual then suggests wiping inside the guide tracks with a cloth dampened with mineral turps or methylated spirits, and Steel-Line says to keep oil and grease out of the tracks altogether.
Force settings are another matter. They are part of how the opener decides it has hit something, so leave them to the door specialist. Afterwards, run the reversal test: Gliderol suggests a 40mm block on the ground, and the safety guide sets out the monthly check.
Never coax it down or duck under it
Steel-Line's sectional door manual says never to stand, walk or drive under a moving door, and warns that children playing 'beat the door' can be seriously hurt or killed. Don't stand in the opening to help a door down, and never press close and dash beneath it. If the door hangs crooked or a cable has come loose, stop: Steel-Line says the lift cables carry the door's whole weight and should be replaced only by experienced door personnel, so that is never one to try yourself.
Garage door not closing all the way
A door that stops short of the floor may have a problem with its travel limits, the points where the opener is told to stop. Steel-Line's opener FAQ says electronic limits should reset themselves even after a power failure, so a door that still won't close fully has something else wrong with it and needs a professional.
Older openers with manual limits are set by hand, and Steel-Line sends owners to the instruction manual or a professional. Merlin's homeowner page shows why care matters: if the door isn't engaged to the opener's trolley while the limits are set, the trolley can travel on and jam into the powerhead.
The gap left behind matters too. Merlin's MJ3800 manual says the gap under the door must not exceed 6mm, or the safety reversal may not work properly, which makes a door that settles a little high more than a draught problem.
Pulling it down by hand is no fix if it fights you. B&D's Smart Pro manual says a released door should move smoothly, and that one needing repair or adjustment shouldn't be used.
Won't close after a power cut or after pulling the red cord
Pulling the release separates the door from the opener, so the motor can run while the door stays where it is. To reconnect, Merlin says to pull the cord down firmly once more. Other openers do it their own way. If the motor runs and nothing happens, Steel-Line's FAQ says to check whether the door was left in manual mode after a power failure.
Gliderol says its motors usually keep their travel limits through an outage, but the remotes may need programming again. If the wall button closes the door and the remotes don't, that is the likely reason, and programming a remote is the next step.
If the power is still off and the door is stuck up, read opening a garage door without power before touching the cord. Chamberlain says to use the release only with the door fully closed where possible, and Merlin warns that an open door with weak springs may come down fast.
Garage door won't close automatically
Timed closing depends on beams. Merlin's MT3850EVO manual says its timer-to-close feature needs safety beams fitted, and that its warning gives 8 seconds of beeps and flashing lights before the door starts down. Steel-Line says its own auto-close timer only works with photo eye beams fitted.
So if the door stopped closing on its own after the beams were bumped, moved or disconnected, start there. If it closes normally from the remote but never by itself, the timer setting is one for the door specialist to look at.
What to tell the door specialist
- Whether the door stays up, stops part way, or reverses near the floor
- Any lights flashing on the opener or the beams, and how many times
- Whether the beams look clean and lined up, and what their lights show
- Anything that changed lately, such as building work nearby or a beam knocked by a car
- Whether the door is open now and the garage can't be secured
- The opener's brand and model, from the label on the motor
What you can do, and what to leave
You can
- Clear the doorway and wipe both beam lenses
- Realign the beams if your manual shows how
- Clean the tracks once the door is down and the opener is disengaged
- Run the reversal test from the safety guide
Leave to a door specialist
- Travel limits and force settings
- A crooked door, a loose cable or a door off its track
- Springs and anything else under tension
- Fitting new beams or changing their wiring
What we would do
Check the beams before you send the job, then say exactly what you found. 'Lenses wiped, both beam lights steady, door still turns back' lets the door specialist skip the beams and go straight to the tracks, the limits or the force setting, which is where the real work is.