Why Is My Automatic Door Not Opening? A Fitter's Guide

Start with the two-minute checks

Before assuming the worst, check the basics. A surprising number of the call-outs we attend turn out to be a switch or setting rather than a genuine fault, and knowing this can save you a call-out charge.

Most automatic doors have a programme selector, either a key switch, a rotary dial or a small digital pad near the door. If it has been knocked to Off, Exit Only or Locked, the door will sit there doing nothing. Cleaners and closing staff change these settings all the time, so it is the first thing worth looking at.

• Check the programme selector is set to Automatic, not Off, Locked or Exit Only
• Confirm the door has power, look for indicator lights on the operator or selector
• Check your fuse board or isolator switch, door operators are often on their own circuit
• Look for anything blocking the track or threshold, a doormat edge or grit is enough on some sliders
• Wipe the sensor lens above the door, a film of dirt or cobwebs can stop it detecting people

Sensor problems are the most common cause

If the door has power but ignores you, the activation sensor is the likely suspect. These sit above the door and use microwave or infrared detection. Direct low sun, heavy rain on the lens, a flapping banner or even a hanging Christmas decoration in the detection field can confuse them. In winter we regularly attend doors that stop working on frosty mornings because condensation has formed inside an ageing sensor.

Safety sensors cause the opposite trick. They are designed to hold the door open or stop it moving if something is in the way, but a misaligned or faulty safety beam can convince the door there is a permanent obstruction, so it refuses to cycle at all. If the door twitches or starts to move then stops, a safety sensor fault is a strong bet.

Mechanical and motor faults

Sliding doors run on a toothed belt and rollers inside the header. Belts stretch and eventually snap, rollers wear flat, and when either happens the motor may run while the door barely moves, often with a grinding or slapping noise. Swing door operators have gearboxes and spring mechanisms that wear in a similar way, usually announced by the door slowing down or juddering before it fails outright.

Age matters here. Most operators are designed for roughly ten to fifteen years of service, and a busy shopfront door in a town centre can cycle hundreds of thousands of times a year. If your door is past that age and parts are failing, it is worth asking an engineer whether repair or replacement makes better financial sense, because obsolete operators can be hard to source parts for.

When to call an engineer, and what it might cost

If the quick checks above have not fixed it, it is time for a professional. Automatic doors are covered by BS EN 16005, the UK safety standard for powered pedestrian doors, and a door that has failed once should be checked properly rather than coaxed back to life, particularly in premises used by the public.

Costs depend on the fault. A sensor adjustment or minor repair is typically at the lower end, while a replacement activation sensor, belt or motor costs more, and a full operator replacement is a bigger job again. Any reputable local firm should diagnose the fault first and quote before carrying out work. If your door serves a care home, pharmacy or GP surgery, say so when you call, as most engineers will prioritise premises where a failed door creates an access or safeguarding problem.

• Door is stuck open or closed on a public entrance, treat as urgent
• Grinding, banging or burning smells, switch the door off at the isolator and call
• Door moves but slams or closes too fast, this is a safety issue under EN 16005
• Repeated intermittent faults, these rarely fix themselves and usually worsen