Photo-Eye Sensor Alignment or Replacement: preparing for the visit

The 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.

Worth answering before the call

Is there frost, snow, slush or salt around the sensors in winter? 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?

Do sensors wear out with age?

They do, slowly. The infrared emitter and the receiver dim over many years, lenses craze or cloud from sun and salt, housings crack, and water finds its way in at floor level. A pair that needs re-aligning more and more often, or whose light drifts between steady and flickering with nothing touched, is usually ageing. Because pairs are matched to the opener, an older opener is worth identifying early so the right replacement is on hand.

What can I check myself before calling?

Three things, all safe. Look along the floor between the sensors for anything in the path, including snow, leaves or a cobweb across a lens. Look at the two sensor lights and note whether one is dark or flickering, or both are dark. Press close and count the flashes of the opener light. If moving an object or wiping a lens brings the receiving light back on steadily, the door may close normally again; if not, those observations make the visit shorter.