Why gates reverse
Automated gates are designed to stop and reverse if they sense something in the way. That protects people, pets and cars. So when a gate reverses for no obvious reason, it almost always means one of its safety devices thinks there's an obstacle, or the motor is meeting more resistance than it expects.
1. Dirty, blocked or misaligned photocells
The photocells are the small sensors on each side of the drive. If the beam between them is broken while the gate is closing, it reverses. Wipe both lenses, cut back plants, and check nothing has knocked one out of line: a bumped photocell is one of the most common causes. Low sun shining straight into a sensor can trigger it at certain times of day.
2. A pressed or damaged safety edge
Many gates have a rubber safety edge along the leading edge. If it's split, crushed or its cable is damaged, the gate can think it's hit something every time. Look for visible damage, but leave repairs to an engineer.
3. Stiff hinges or a dropped gate
If a hinge is rusty, or the gate has dropped and now drags on the ground, the motor has to push harder. Modern control boards read that extra effort as an obstacle and reverse. If the gate scrapes, judders or squeals, this is the likely cause, and fixing it early saves the motor.
4. Wind
Solid gates catch the wind like a sail. On a gusty day, the force pushing against a closing gate can trigger the obstacle detection. If it only happens in the wind, an engineer can review the force settings, the motors and whether the gate design suits the site.
5. Force settings and a tired motor
Every control board has force and sensitivity settings. If they're set too tight, or a worn motor is struggling, the gate can reverse part-way. Adjusting these settings is a job for a trained engineer, because they're what stop the gate hurting someone.
Never bypass the safety devices
It can be tempting to disconnect a photocell or turn the sensitivity right down to stop the reversing. Don't. Those devices are what stop a heavy gate crushing a child, a pet or a car. If they're the problem, they need fixing, not removing.