Repeated opening and closing

• Causes

1. Door interlock electrical contacts (door lock switch) jammed / burnt, obstructed detector.
2. Misalignment of door reopening devices

• Inadequate cleaning maintenance that cause infrared detector lenses to be dirty and it will prevent the receiving unit to see the infrared beam, causing the door to be remain open and close.

Burnt door lock switch

• Good practices

The protective device shall automatically initiate re-opening the door when there is an obstruction crossing the entrance during closing movement. The devices should be positioned in a way to minimize risk of damage or injury due to jamming of a part of a person or other object (SS550).

• Corrections

To reduce the risk of elevator doors striking passengers while they are entering or exiting the car, it is recommended to install newer detection devices such as multi-beam sensor. It is a type of door sensor that uses multiple infrared beams to monitor the entire doorway.

Multi-beam elevator door sensor [33]