Safety Devices Knocked Out of Line
A gate that reverses for no reason, or will not close at all, is frequently reporting a real fault in the only way it can. Photo eyes are the usual cause, and they are easy to disturb: a leaf that sags carries its beam with it, a post that leans shifts the sensor, and a mower or a delivery truck can nudge a housing by a few degrees.
A through-beam photoelectric sensor needs its emitter and receiver aimed at one another, and a misaligned pair gives false trips. Dirt on a lens, or low sun shining straight into a receiver, can trip the same sensor even when it is aimed correctly. We realign the pair, clean the lenses, and move a housing when its position is the cause.
Contact edges take knocks too. A crushed or cut edge, or a cable pulled loose by a swinging leaf, will stop a gate on every cycle. We replace damaged edges and reroute the wiring so the leaf no longer works on it.
UL 325 requires at least two independent means of entrapment protection per direction of travel where an entrapment zone exists, and the operator checks its external devices as the gate moves. Because of that, a bypass wire or a jumper that someone added to get the gate moving again is something we take out, not leave in. After every repair we test each device in both directions, and the test is the last thing we do before we hand the remote back to you.