

Openers · Midhurst
Photo-Eye Sensor Alignment or Replacement in Midhurst
The door will only go down while a finger stays on the wall button; let go and it stops or reverses.
In plain words
If your opener has no sensors at the floor, that alone does not date it, since a pair can be missing, removed or never reconnected; the technician identifies the model before deciding whether a pair can be restored or the operator itself needs replacing. The visit is still worth making: the technician tests contact reversal and sets out what a modern operator brings, including a matched sensor pair, force reversal and a monitored circuit that holds the door open until the beam clears. Where sensors are present but tucked up beside the motor, they are returned to the doorway where they belong.
How the visit goesOn bright mornings the door will not close, then by lunchtime it behaves itself. The garage faces the low sun, and the light reaches straight across the floor to one of the little black sensors.
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.
Dealing with the sun
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.
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
Wall or floor angle brackets
Matched photo-eye sensor pair
Track-mount sensor brackets
Wire connectors
Receiving-eye sun shade

Photo-Eye Sensor Alignment or Replacement
What affects the quote
Opener make and generation
Sensor pairs are matched to the opener family, and some models take a kit with brackets and wire while others take sensors alone. The head unit label sets which pair is needed and how it is priced.
Wall or floor mounting with anchors
Mounting into concrete or masonry rather than onto the track means drilling, anchors and sealing against water, which takes more time than clipping to the rail.
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.
What to have ready
- Are there sensors at the floor on both sides, or are they missing or mounted up beside the motor?
- 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?
Photo-Eye Sensor Alignment or Replacement: questions
QuestionsWill the sensors need replacing or just aligning?
Most visits end in alignment, cleaning and bracket work, because the sensors themselves are hardy. Replacement comes into it when a lens has clouded or crazed, when the housing is split or holds water, an indicator stays dark with the wiring proven good, or the pair is from a different generation than the opener and is never recognised. The technician tests before choosing, so the parts list matches what the door needs.
My opener has no sensors at all. Can they be added?
If the opener predates the entrapment-protection standard, which operators have had to meet since the mid-1990s, its board has no sensor circuit and a pair cannot simply be wired in. The positive news is that a modern operator brings the whole package: matched sensors, force reversal and a monitored circuit. The technician confirms the model first, because some units do have the terminals and simply had their sensors removed.
Do both sensors get replaced together?
Yes. The sending and receiving sensors are made and sold as a matched pair for a given opener family, and the head unit expects both to be from the same generation. Fitting a pair also means both lenses, both indicators and both mounting points are fresh at the same time, so the alignment holds and the next check is simpler. A single sensor from an unrelated kit is where mystery faults come from.
Related services

- Chain-Drive Opener RepairThe chain hangs in a loop under the rail and slaps against it on every cycle.
- Belt-Drive Opener RepairThe door used to glide up with a soft hum.
- Garage Door Opener ReplacementSince the storm the door behaves oddly: it reverses halfway down for no reason, the light flickers, and the travel limits drift so it either slams or stops short.