Sound familiar?Waterdown
- The call
- You press the remote, the door drops a few centimetres, then climbs straight back to the top while the opener light blinks. Nothing is under the door. It has done this every evening this week.

Two small sensors face each other across the doorway: one sends an infrared beam, the other receives it. While the beam lands on the receiver, the opener will close the door; the moment anything interrupts it, the door stops and returns to open. Every sensor call comes down to why the receiver has lost the beam: an object, a bent bracket, a dirty or frosted lens, sun in the receiving eye, a broken wire or a tired sensor. The technician works through those in order, fixes the one that applies, and shows you the steady indicator lights that mean the pair is talking again.
Sound familiar?Waterdown
Photo-Eye Sensor Alignment or Replacement · Waterdown

Scene 1
The two sensors have to sit at the same height, level, and facing each other squarely, no higher than about 15 cm (6 in) above the floor so the beam catches a small child or a pet. The technician measures both sides, because a bracket that has slipped a couple of centimetres down a track leg is enough to lose the beam. Each bracket is checked for bends from a bumper or a bin, for loose carriage bolts or wing nuts, and for rust where salt slush has sat against it for winters on end. A bracket screwed to a wall or the floor is checked for anchors that have worked loose.
Scene 2
A receiver that looks into the low sun is fixed by geometry. The simplest cure is to swap the two sensors side to side so the receiver looks away from the doorway light and the sending eye, which is not affected, takes the sunny position. Where the layout rules that out, a small hood or shade is fitted over the receiving lens, deep enough to shield it without narrowing the beam path. The wiring is extended or re-routed as needed and both lights are checked at the time of day the fault used to appear, or with a strong light aimed at the lens to stand in for the sun.
Scene 3
You leave knowing what normal looks like at the floor. Most sensor pairs carry a small indicator on each side, often in different colours for sender and receiver, though some older pairs light only the receiver; the model's own chart tells you what steady and flickering mean. A dark or flickering light on the receiving side means the beam has been lost, usually because a bracket was bumped or something is in the path, and two dark lights mean the pair has lost power along the wire. A glance at those lights before calling anyone tells you most of what the technician would look at first, and often the fix is moving whatever is leaning on the bracket.
What shapes the quoteMount Nemo Door Specialists
FeesSame any hour
Two, and you are invited to watch. With the door closing, an object is passed through the beam and the door has to halt and climb back to the top. A 2x4 laid flat beneath the door's centre comes next; closing onto it must make the door back off on contact. The door is also run from the wall control and a remote, the opener's warning flashes are confirmed gone, and both sensor lights are shown steady.
Arrangement varies by model: most pairs carry an indicator on each side, in differing colours for sender and receiver, though some older pairs light only the receiver, so check the maker's chart. A receiving light that is dark or flickering means the beam is not landing on it, so the pair needs aligning or something is in the way. Both lights dark means the pair has no power, which points to the wire or the terminals at the head unit. Steady lights on both sides mean a healthy system.
Gently, with a soft dry or lightly damp cloth, the way you would clean eyeglasses. Never scrape a lens or use a solvent, since a scratched or clouded lens scatters the beam. Wipe both sensors, then check that the receiving light comes on steadily. If a lens frosts on cold mornings, give it a few minutes to clear or dry it with a cloth. A quarterly wipe keeps dust, cobwebs and salt film from building up.
HamiltonOntario
Photo-Eye Sensor Alignment or Replacement · Hamilton, Buchanan, Central, Chedoke Park, Cootes Paradise, Corktown, Hamilton Beach, Hopkins Court, Hopkins Survey, McDonald Court, North End, University Gardens, West Hamilton, Westdale, Pleasant View Survey
Every square is one home in a hundred.
On-site assessment
Since shelving went up along the garage wall, the door will not close and both sensor lights are dead.
(289) 203-0726, open 24/7.
On-site assessment preferred · (289) 203-0726, open 24/7