How to handle an automatic door that opens too fast or closes too slowly

1. Why an automatic door opens too fast or closes too slowly

The opening and closing speed of an automatic door is controlled by the sensor system, the motor and the controller. When any of these components becomes misconfigured or worn out, the door may react unpredictably, such as opening too fast and surprising users or closing too slowly and creating safety concerns. Understanding the root cause allows you to fix the problem correctly and avoid further damage.

1.1 Sensor detects movement incorrectly (too far or too close)

A sensor that scans too far will trigger the door to open quickly even when detecting small movements from a distance, creating sudden reactions for nearby users. If the sensor detects too close or is covered with dust, the door may respond slowly, close unevenly or fail to close completely, affecting both safety and energy efficiency.

1.2 Motor loses torque or is programmed with an incorrect speed

A weakened motor, reduced pulling force or an overly high programmed speed can cause the door to open too fast and create unsafe reactions. Conversely, a weak or friction-affected motor makes the door close slowly and prevents it from reaching its standard operating speed during daily use.

1.3 Belt slipping, worn rollers or dirt buildup on the rail

When the timing belt slips or the rollers wear out, the system loses proper traction and the door gradually slows during the closing phase. Dust and sand accumulated on the rail also increase friction, making the door heavier, less smooth and more likely to respond slowly than normal.

1.4 Controller improperly configured (travel path or speed settings)

A controller with incorrect travel settings or speed parameters is one of the most common reasons for abnormal opening and closing speeds. Electrical pulse errors, wrong configuration or improper adjustments can all cause the controller to react incorrectly and reduce the stability of the entire door system.

2. How to diagnose and fix an automatic door that opens too fast

A door that opens too fast can startle users and create safety risks for children, elderly people or anyone standing close to the opening area. By identifying the correct cause and adjusting the related components, the door can operate more smoothly and safely in all environments.

2.1 Adjust the sensor’s sensitivity and scanning range

An overly sensitive sensor or one with an excessively wide scanning range will cause the door to open too quickly at the slightest movement. You can adjust the detection angle or reduce the sensitivity according to the manufacturer’s instructions, while also cleaning the sensor surface to prevent dust from affecting detection accuracy.

2.2 Reduce the opening speed through the controller settings

The controller allows users to set the door’s opening speed based on safety standards. If the door opens too fast, simply reduce the programmed speed to a level suitable for the door type and the traffic load. All adjustments must follow the correct technical procedure to avoid misalignment of the travel path.

2.3 Check whether the motor is overloaded or incorrectly programmed

A motor programmed with the wrong speed or operating under overload conditions may cause the door to open sharply and unexpectedly. Pay attention to its temperature, vibration and pulling force. If the motor heats up quickly or vibrates strongly, immediate inspection or technical support is required.

2.4 When fast opening becomes a safety hazard

If the door opens forcefully, produces a strong push or reacts even when no one is nearby, this indicates a serious safety risk. Such conditions can easily cause collisions with children, elderly individuals or people moving close to the door, especially in busy areas such as shops, offices or shopping centers.

3. How to handle an automatic door that closes too slowly or refuses to close

A door that closes too slowly affects energy efficiency, disrupts pedestrian flow and may cause safety issues. Identifying the correct cause and applying the right adjustments ensures the door closes at the proper speed and maintains reliable operation in busy environments.

3.1 Recheck the closing timer and travel speed setting

The controller includes a delay timer that determines how long the door waits before closing. If the timer is set too long, the door will take excessive time to close. Adjust the timer to the standard interval so the door begins closing at the correct moment without unnecessary delay.

3.2 Clean the safety sensor and presence sensor to prevent false detection

Dust, moisture or small objects covering the lower safety sensor can make the door think that someone is still standing underneath, causing it not to close or to close very slowly. Cleaning the sensor area and confirming the detection zone helps restore accurate recognition.

3.3 Inspect the rail, timing belt and rollers for resistance

Slow closing is often caused by reduced pulling force due to a loose belt, worn rollers or debris trapped along the rail. Observe the movement, listen for unusual noise and check for obstacles. A simple cleaning, lubrication or tightening of moving parts can often restore proper operation.

3.4 Reset the controller when electrical pulse errors occur

If the door fails to complete its closing path, closes then reopens or closes extremely slowly without a clear cause, the controller may have a pulse error. Resetting allows the system to recalibrate its travel path. If the issue persists after resetting, deeper inspection of the motor or controller is required.

4. When you should call for professional technical support

Certain speed-related issues are beyond what users can safely handle. Attempting to adjust these settings without experience can lead to incorrect travel paths, reduced equipment life or serious damage to the motor and controller. Calling a technician at the right time ensures safety and long-term stability.

4.1 Issues persist even after troubleshooting steps

If you have already cleaned the sensors, adjusted the timer or performed a controller reset but the door still opens too fast, closes too slowly or behaves inconsistently, the system may have deeper problems. A technician must inspect the motor, belt and controller configuration to identify the exact cause.

4.2 Motor overheating, strong vibration or unusual noise

A motor that overheats, vibrates excessively or produces strange sounds is a critical warning sign. These symptoms often indicate overload or a failing coil. Continued operation may cause motor burnout or unexpected door blockage, creating significant safety hazards.

4.3 Controller not responding or showing complex configuration errors

The controller is the “brain” of the automatic door. If the circuit board malfunctions, signals are incorrect or settings are corrupted, users cannot repair it manually. Technicians must use specialized tools to measure, reset or reprogram the controller parameters according to the door’s size and load.

4.4 Door located in a high-traffic or critical facility

In shopping malls, restaurants, hospitals or facilities with heavy foot traffic, any issue with door speed must be resolved immediately to ensure safety. Timely technical support helps prevent accidents and maintains a smooth, uninterrupted flow of movement for all visitors.

Adjusting the opening and closing speed correctly ensures the automatic door operates smoothly, safely and in harmony with the building’s daily traffic. By identifying early warning signs and applying the right troubleshooting steps, you can prevent damage, extend motor lifespan and maintain long-term stability. However, if the door continues to malfunction or shows dangerous symptoms, contacting a professional technician is essential to prevent risks.

If you need help inspecting or adjusting the speed of your automatic door, contact Thuy Linh Long. We offer on-site assessment, precise calibration and fast support to ensure your door operates safely and smoothly at all times.