Why Your Garage Door Reverses Just as It Touches Down

What causes it

These are the causes we find most often, in roughly the order we check them.

1. 1

   Sun glare swamping the photo-eye receiver

   The receiving eye reads an infrared beam. Low sun angling straight into the lens, which happens in west-facing Perth garages through the late afternoon, floods the sensor with infrared until it can no longer pick out its own beam. The opener reads that as an obstruction and reverses.

   What you can check

   Note the time of day and where the sun is when it happens. If the door closes fine in the morning but reverses every afternoon between about four and six, glare is almost certainly the cause rather than a component fault.

   What we do

   We swap the transmitter and receiver sides so the receiver faces away from the sun, fit shrouds over the lenses, or relocate the pair to a shaded position on the jamb. All three are quick and none of them compromise the safety function.

2. 2

   Down limit set past the floor line

   The opener stores a target position for the closed door. If that target sits below the slab, the door lands, the opener keeps driving, the load spikes and the safety logic reads it as hitting something. The result is a door that touches down and then goes straight back up.

   What you can check

   Watch closely at the moment of reversal. If the bottom seal makes contact with the slab and the motor pushes for another half-second before the door lifts, the down limit is set too far. A door that reverses before it reaches the floor is a different fault.

   What we do

   We reset the down limit so the door just seats on its seal without straining, set the down force to the lowest reliable value, then re-test the reversal against a 40mm timber block. On mechanical-limit openers we lock the adjustment so it cannot creep back.

3. 3

   Hardened bottom seal or an uneven slab

   The rubber weather seal squashes to make a light-proof line along the floor. Once it hardens with age, or where the slab has heaved or been re-poured with a fall, one part of the door meets solid concrete before the rest and the opener sees an obstruction.

   What you can check

   Close the door by hand and look along the bottom for daylight. A seal that is flattened, cracked or missing sections, or a floor line with an obvious high spot, tells you what the opener is running into.

   What we do

   We fit a new bottom seal in the correct profile for your bottom rail, and where the slab is genuinely uneven we use a deeper or stepped profile to take up the difference. It also fixes the draught, the leaf litter and the water that come with a worn seal.

4. 4

   Down force set too low as the springs age

   The down force setting stops the door crushing anything. As springs lose tension the door grows heavier, which changes the load the opener sees on the way down. A setting that suited the door five years ago now trips near the end of travel, every single time.

   What you can check

   Pull the release and lower the door by hand from head height. It should come down at a steady, controlled pace under light hand pressure. A door that runs away from you, or one that needs pushing, has a balance problem sitting behind the reversal.

   What we do

   We rebalance the door and replace tired springs first, then set the force. Winding the force up without fixing the balance is the wrong order: it papers over the fault and removes the very margin that lets the opener detect a genuine obstruction.

5. 5

   Photo-eye bracket vibrating out of alignment

   The eyes sit on light steel brackets bolted to the track. A loose bolt lets the bracket rotate slightly every time the door runs. The beam clips the edge of the receiver right at the end of travel, and the door reverses at almost the same point each time.

   What you can check

   Watch the indicator light on the receiving eye through a full close cycle. A light that flickers or goes out just as the door nears the floor, then comes back on, points at a bracket that is moving rather than at a dirty lens.

   What we do

   We tighten and shim the brackets, refit them to solid steel rather than a flexing track lip, and re-aim both eyes so they hold alignment through a full cycle. Brackets bent past use are replaced and the wiring is re-run and clipped properly.

6. 6

   Binding at the bottom of the vertical track

   The last 300mm of travel is where tracks are most often damaged, by a mop handle, a bike pedal or a kerbed bumper. The bottom roller meets the pinch, the load jumps, and the opener reverses at the same height every time even though nothing is on the floor.

   What you can check

   Look into both vertical tracks at knee height and below. Bright rub marks, a crease in the track lip, or a track pushed out of line at the bottom bracket are all visible with a torch and a couple of minutes.

   What we do

   We replace the damaged track section, re-plumb both verticals to the door and reset the spacing to specification. Bottom rollers that have flat-spotted from riding a damaged track are replaced at the same time so the new track does not get chewed.