Ceiling Mount Line Voltage Occupancy Motion Sensor

A motion sensor detects a moving object. An occupancy or vacancy sensor is a kind of motion sensor that specifically detect whether the room is occupied or unoccupied(vacant). You may see ceiling motion sensor or ceiling occupancy sensor refers to the same sensor.

An occupancy sensor detects people’s presence when they enter and leave the room and automatically controls the light. It automatically turns on the light upon the detection of motion and turns off automatically after the room is vacant and no motion is detected. An occupancy sensor is also an auto-on, auto-off sensor. Ceiling motion sensors are mostly occupancy sensors, a fully automatic lighting control.

An occupancy sensor that automatically turns lighting off within 30 minutes is often installed in classrooms, conference rooms, break rooms, storage rooms, printing rooms, private offices, restrooms, dressing rooms, and storage rooms.

A vacancy sensor requires the user to manually turn on the light using a switch, and then the vacancy sensor automatically turns off the light after the room is vacant and no motion is detected. A vacancy sensor is also a manual-on, auto-off sensor. Vacancy sensor is mostly seen used on wall switches, also known as a motion sensor light switch, or vacancy sensor switch.

A vacancy sensor is often installed to control lights in bathrooms, garages, laundry rooms, and utility rooms.

The occupancy sensor fully automatically turns on/off the light, while the vacancy sensor requires users to manually turn on the light and it will automatically turn off the light.

Many occupancy sensors provide both working modes that allow users to select either occupancy or vacancy mode, which is usually seen on a motion sensor wall switch. Ceiling-mounted detectors are mostly occupancy sensors.

PIR occupancy sensors or vacancy sensors utilize passive infrared(PIR) technology for detecting motions. The PIR motion sensor passively detects the heat (infrared) emitted by human bodies in motion. When a warm body walks across the motion sensor, it can detect the difference in heat, register a valid signal, and turn on the light. When the PIR motion sensor cannot detect the difference in the received heat signals, it will think there are no moving objects and thus turn off the light.

There are also other technologies like ultrasonic and microwave occupancy sensors that detect motion by actively sending out detecting signals and comparing the differences in the received signals. There are also dual technology occupancy sensors that use both a PIR motion sensor and an ultrasonic motion sensor to detect motion more accurately.

Most ceiling mount occupancy sensors are PIR motion sensors and the best advantage of PIR technology is that they are very durable, highly energy efficient, and can have a clear field of view from the ceiling. And most of the time, they are qualified for the work, cost-effective and maintenance-free.

You cannot turn off an occupancy sensor because the occupancy sensor works automatically and will only turn off the light after the sensor cannot detect a motion after the time delay.

To manually turn off the light controlled by an occupancy sensor, you need to add a wall switch with additional wirings.

Energy code such as ASHRAE 90.1, IECC and Title 24 requires energy conversion and efficiency. These energy codes require occupancy sensors to be used in many residential and commercial spaces. The lighting in these spaces shall be controlled by an occupancy sensor and automatically dims or shut off when lighting is not in used within 20 mins.

Wireless occupancy sensors have batteries. Rayzeek occupancy sensors are all line-voltage powered and do not require batteries.

The Lights Won’t Turn On

Wired Incorrectly

Check if the green indicator flashes or not. If it flashes, check the load wiring or the load function. If not, check if the wiring is the same as the wiring diagram.

Bulbs Blown

Ambient Light is brighter than the selected light sensor value. Check if the bulb still functions or replace it.

Ambient Light Is Brighter Than the Selected Light Sensor Value

Draw the curtain to make the room darker, wave your hand, and check if the light turns on. If it turns on, adjust the light sensor value to 35Lux, or off to see if the light turns on.

Sensor Not Detecting Your Movement

Move closer to the sensor.

Lights Stay On

Time Delay Set Too Long

Adjust the time delay to 15 seconds and check if the light will turn off.

Wired Incorrectly

Check if the wiring is the same as the wiring diagram.

Frequent Changes in Heat Are Being Detected

Aim sensor away from heat sources, heat vent, air condition, pet.

Lights Keep Turning On and off (Cycling)

Wired Incorrectly

Check if the wiring is the same as the wiring diagram.

Changes in Heat Are Being Detected From a Fixed Heat Source

Check the sensing area for a heat source, and reposition the sensor.

Light and Heat are being Reflected Back Onto the Sensor

Alter the aim of the sensor or paint the reflecting surface with a dull finish.

Sudden Temperature Changes Due to Storms or High Winds

Turn the sensor off until the storm passes or install it in a sheltered location.