Five signs your automatic door sensors need attention

An automatic door is only as good as its sensors. The motor and drive move the door, but the sensors decide when to move it and, more importantly, when not to. When they start to drift, the symptoms are easy to spot if you know what to look for.

The two jobs sensors do

Most automatic sliding and swing doors use two kinds of sensing, often combined in one unit above the door:

• Motion (activation) sensors — usually microwave radar. They detect people moving toward the door and tell it to open.
• Presence (safety) sensors — usually active infrared. They detect anyone standing still in or near the doorway and stop the door from closing on them.

Many doors also have safety beams or photocells across the opening, and swing doors often have sensors mounted on the door leaf itself to stop it hitting someone on the swing side.

Activation problems are an inconvenience. Presence problems are a safety issue. Knowing which is which tells you how urgent the fix is.

Sign 1: The door opens for no one

"Ghost opening" wastes energy, lets dust and heat into an air-conditioned space and annoys staff. Common causes:

• The detection field is too large and picks up people walking past rather than toward the door.
• Movement in the field: a banner, a flag, plants, or a sign swaying in the AC airflow.
• Vibration from heavy traffic, or a loose sensor bracket.
• Reflections from a polished floor or glass on a sunny day.

Fix: remove moving objects from in front of the door, then have the sensor's field size, angle and direction re-set. Most motion sensors can be set to detect only movement toward the door.

Sign 2: People reach the door before it opens

If customers slow down or step back because the door opens late, the sensor's range has dropped. The usual culprit in Riyadh is dust on the sensor window, followed by a sensor that has been knocked so it now points at the floor or the ceiling.

Fix: gently wipe the sensor cover with a soft, dry cloth (no sprays or solvents). If that doesn't help, the sensor needs re-aiming and its sensitivity adjusting.

Sign 3: The door starts closing while someone is in the doorway

This is the one not to ignore. If a door begins to close on a person, trolley or wheelchair standing in the threshold, the presence detection isn't working properly. Causes include a failed or dirty infrared sensor, a sensor that has been knocked out of position, or settings that were changed.

What to do now: switch the door's program selector to "open" or "manual" so it can't cycle, keep people clear, and call a technician. Don't keep using the door in automatic mode.

Sign 4: The door won't close, or keeps reopening

An infrared presence sensor learns what the empty doorway looks like. If something in its field changes, it may decide someone is standing there and hold the door open. Typical triggers:

• A new floor mat, a promotional stand or a delivery left near the threshold.
• Sand drifting across the floor after windy weather.
• Strong sunlight hitting the floor at a certain time of day.
• A dirty or wet sensor cover.

Fix: clear the area, clean the sensor cover, and restart the door using the program switch, which makes many sensors relearn the background. If the problem continues, the sensor needs adjustment or replacement.

Sign 5: Hesitation, stuttering or error lights

A door that starts to open, stops, then starts again — or a sensor whose indicator LED keeps changing colour — often points to an intermittent fault: a loose connector, damaged cable, failing sensor or a power-supply problem in the operator. Many operators also log error codes that a technician can read to find the cause quickly.

What you can safely do yourself

1. Keep the area in front of and below the door clear of signs, plants and mats that move or change.
2. Wipe sensor covers with a soft, dry cloth once a week in dusty periods.
3. Learn where the program selector is and what each setting does.
4. Write down when problems happen (time of day, weather, how busy) — it helps diagnosis a lot.

Leave sensor settings, door speeds and forces to a trained technician. These settings protect people, and changing them without test equipment can make a door unsafe.

How often should sensors be checked?

Sensors should be tested on every service visit, and busy entrances in Riyadh benefit from a check every three to six months. Our automatic door maintenance includes sensor cleaning, re-aiming and a full safety test, with a written report for your records.