Openers · Woburn
Photo-Eye Sensor Alignment or Replacement in Woburn
The small light on one of the sensors near the floor has gone dark, or it flickers when someone walks past the track.
In plain words
The sensors are only as good as the thin two-conductor wire that links them to the opener. It runs from the low-voltage terminals on the head unit along the ceiling and down each wall to the floor, stapled as it goes, and it is easily pierced, cut during renovations, chewed, or pulled loose at the terminals. When both sensor lights are dark, or the opener's code says the circuit is open or reversed, the technician tests the run end to end, repairs the damaged section or replaces the whole run, checks polarity at the terminals, and clips the new wire clear of the track.
How the visit goesThe small light on one of the sensors near the floor has gone dark, or it flickers when someone walks past the track. The other one glows steadily. The door refuses to close from the car.
Photo-Eye Sensor Alignment or Replacement
How the visit goes
Making sure it is the sensors and not the door
A door that reverses on the way down has two possible reasons, and only one of them lives at the floor. If the door touches something, including a bottom seal frozen to the slab, a travel limit set slightly long or a stiff door in cold weather, the force setting sends it back up. That looks like a sensor fault from the driveway but calls for a different fix. The technician checks whether the door reverses before it moves or after it meets resistance, watches the sensor lights during the cycle, and tries the door with the beam deliberately shaded. The answer decides whether the work stays with the sensors or moves to the settings.
Proving it with the two tests
No sensor job is finished on a steady light alone. The door is closed from the wall control and from a remote, and while it is on its way down an object is passed through the beam; the door must stop and return to fully open. Then a 2x4 is laid flat on the floor under the centre of the door and the door is closed onto it; it must reverse on contact. Both are repeated, the opener's diagnostic light is confirmed clear, and any app or hub reporting a sensor code is refreshed. The customer watches the tests so the normal behaviour is seen, not described.
Wiring that stays put
The wire between the head unit and the sensors has been secured along the ceiling and walls, clipped clear of the track and, where it was exposed, run inside a protective channel. Two things keep it that way. First, when anything is fastened to those walls or that ceiling, from shelving to a bike hook to drywall, look for the thin wire before driving a screw or a staple. Second, if mice have been in the garage, a chewed wire is a common sign, so a dark sensor light after a sighting is worth a look at the run. Either way, the sensor lights will tell you the moment the circuit is open.
Photo-Eye Sensor Alignment or Replacement
In the van
Two-conductor low-voltage wire
Wing nuts and carriage bolts
Wall or floor angle brackets
Insulated wire staples
Matched photo-eye sensor pair
Photo-Eye Sensor Alignment or Replacement
What affects the quote
Corrosion reaching the head unit
Where salt and water have travelled up the wire to the terminals, or the sensor terminals on the board are damaged, the repair extends beyond the pair and that is set out separately.
Bracket condition
A bracket that can be straightened costs little time. One that is cracked, rusted through or missing is replaced, and a change from track clips to wall or floor brackets adds anchors and mounting work.
Force and travel adjustment alongside
If the reversing turns out to involve a travel limit set long or a force setting made in summer, adjusting and re-testing those settings is included as a small extra step.
What to have ready
- Can you send photographs of both sensors, the head unit label and the wall control?
- What make and model is on the opener's label, and roughly how old is it?
- Can you see the thin sensor wire, and does any of it look pinched, cut or chewed?
Photo-Eye Sensor Alignment or Replacement: questions
QuestionsWhat tests are done before the technician leaves?
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.
How do I test the sensors each month?
Start the door closing and, while it is moving, swing a broom handle through the beam low across the opening; the door should halt and travel back up. Next, put a 2x4 flat beneath the door's centre and run the door onto it; it should back off as soon as it touches. If either test fails, close the door first if you can, use it by hand with the manual release, and book a visit; do not release it if it feels heavy.
The opener light blinks when I press close. Is that the sensors?
Very often, yes. A blinking bulb after a close command is the opener reporting that its sensor circuit is unhappy, and the count of blinks is the message: one common family uses ten flashes for the sensors, while a short two-flash pattern usually means the wall control's lock button is on. Newer units add arrow codes that separate a blocked beam from a cut or reversed wire. Counting the flashes and telling the technician the make helps identify the cause before the visit.
Related services
- Chain-Drive Opener RepairThe chain in the detached garage went orange with rust over the winter, the links are stiff, and the opener strains and groans to pull the door up.
- Belt-Drive Opener RepairThe door used to glide up with a soft hum.
- Garage Door Opener ReplacementYou swapped the old wooden door for a heavier insulated steel one, and the twenty-year-old opener that was kept has never settled.