LEGRAND Watt Stopper DT-305

Questions and Answers

K
Kristen ChapmanJul 27, 2025
What to do if LEGRAND Watt Stopper DT-305 lights do not turn on when entering the room?
- B
  Brandon TaylorJul 28, 2025
  If the lights don't turn on when you enter the room, you should: * Check that the circuit breaker has been turned back on. * Check all sensor and power pack wire connections. * Check for 24VDC input to the sensor between the red and black low voltage wires. If 24VDC is present, replace the sensor. If 24VDC is not present, check the high voltage connections to the power pack. If high voltage connections are good and high voltage is present, replace the power pack.
A
Andrew LewisAug 1, 2025
Why LEGRAND Accessories lights do not turn off automatically?
- R
  Rebecca Leach DVMAug 2, 2025
  If the lights do not turn off automatically, try the following steps: 1. Check all sensor and power pack wire connections. 2. Disconnect the power pack blue wire. If the lights do not turn off, check the power pack wiring. If the lights turn off, the problem may be the sensor or wiring between the sensor and power pack. 3. Reconnect the blue wire. 4. Turn sensitivity and time delay to minimum, and allow the sensor to time out. If the lights turn off, the sensor is working properly – adjust sensitivity and time delay for the sensor. If the lights do not turn off, check the wiring between the sensor and power pack. If the wiring is correct, replace the sensor.
R
Regina SchneiderAug 6, 2025
What to do if red and green LEDs flash on LEGRAND Watt Stopper DT-305?
- J
  Jessica SullivanAug 6, 2025
  If both the red and green LEDs are flashing, take these steps: * Check all sensor and power pack connections. * If a Light Level is connected, verify Light Level functionality is required and press and hold the Light Level button for 5 seconds to make sure it is not holding OFF the load. If Light Level functionality is not required, reference the wire diagrams for proper wire connections. * Check for 24VDC at the power pack blue and black wire connections to sensor while sensor is active. If there is no voltage, replace the sensor. If there is voltage, check for 24VDC between the blue and black wire at the power pack. If 24VDC is present and the relay is not closing, replace the power pack. If 24VDC is not present, check for a break in the low voltage wiring.
A
Alexandra WilliamsAug 11, 2025
What does it mean if the green LED is on continuously on LEGRAND Watt Stopper DT-305?
- C
  crystalsalazarAug 11, 2025
  If the green LED is continuously on, check the ultrasonic sensitivity trimpot. The fully counterclockwise position is the override for the sensor. Turn the trimpot clockwise until the LED flashes only when movement occurs in the desired coverage area.
D
Donald HansenAug 17, 2025
How to fix a LEGRAND Watt Stopper DT-305 when the green LED does not flash?
- H
  Heather GonzalezAug 17, 2025
  If the green LED does not flash, the ultrasonic sensitivity setting may need to be increased. Turn the adjustment trimpot clockwise until the LED begins to flash when movement occurs.
J
jessica19Aug 21, 2025
Why is the red LED not flashing on my LEGRAND Accessories?
- S
  Stephanie WalkerAug 22, 2025
  If the red LED is not flashing, it could be due to a warm-up period of 30 to 60 seconds after power is initially applied to the sensor before the LED becomes active. Also, ensure the PIR sensitivity is set to 100% by verifying that DIP switch #8 is in the “on” position.

Summary

Sensor Placement

Placement Guidelines

Instructions for sensor placement including height and proximity to hot air supplies.

Mounting

Mounting Through Ceiling Tile

Instructions for mounting the sensor through a ceiling tile using spring clips.

Mounting to Octagon Box

Instructions for mounting the sensor to a 4" octagonal J-Box.

Connecting Wires

Wiring Safety Precautions

Notes on separating high voltage and low voltage wiring for safe connections.

Wiring Diagrams

Illustrations of standard and manual-on wiring configurations for the sensor.

Factory Pre-Set Operation

Pre-Set Parameters

Details on factory default settings for time delay, LED indicators, ON mode, PIR, and ultrasonic sensitivity.

Troubleshooting

Lights Do Not Turn On

Steps to diagnose and resolve issues where lights fail to activate when entering a room.

LED Status Issues

Guidance for troubleshooting scenarios involving flashing or non-flashing LEDs on the sensor.

Lights Do Not Turn Off

Procedures to troubleshoot and fix problems where lights remain on automatically.

The DT-305 is a 360° Dual Technology Low Voltage Occupancy Sensor designed for ceiling mount applications. This Quick Start Guide outlines its basic operation, installation, and troubleshooting. For more detailed information, users are directed to the full installation instructions available at www.wattstopper.com. Installation must comply with all applicable regulations and codes.

Function Description:

The DT-305 sensor utilizes dual technology (PIR and Ultrasonic) to detect occupancy within a space, automatically controlling lighting loads. It is pre-set for basic operation but offers optional adjustments for time delay, LED indicators, ON Mode, PIR sensitivity, and Ultrasonic sensitivity. The sensor is designed to turn lights on when occupancy is detected and turn them off after a set time delay when the space is vacated.

Important Technical Specifications:

Coverage Area: 360°
Mounting Height: Maximum 10 feet for optimal sensor placement.
Technology: Dual Technology (PIR and Ultrasonic).
Voltage: Low Voltage (Class 2) for control wiring. High voltage power is handled by a separate power pack.
Factory Pre-Set Settings:
- Time delay: 20 minutes
- LED indicators: Enabled
- ON Mode: Auto-ON (Both technologies must activate to turn on load; either keeps it on).
- PIR sensitivity: High
- Ultrasonic: 80%
Wiring: Requires a power pack for high voltage load control. Connections to the sensor are low voltage.
Mounting Options: Can be mounted through a ceiling tile or to an octagon box (4" octagonal J-Box, at least 1.5" deep).

Usage Features:

Basic Operation: The unit is pre-set for immediate use, turning lights on when occupancy is detected and off after a 20-minute delay when the space is empty.
Adjustments: Users can customize settings such as time delay, PIR sensitivity, and ultrasonic sensitivity. These adjustments are optional and provide flexibility for different environments.
ON Mode: The default Auto-ON mode requires both PIR and Ultrasonic technologies to activate the load initially, but either technology can keep the load on once activated. A DIP switch setting needs to be changed for manual-on wiring with a low voltage momentary switch.
Wiring Configurations:
- Standard wiring with local off switch: Allows for manual control to turn off lights.
- Manual-On wiring with low voltage momentary switch: Enables manual activation of lights using a momentary switch, with specific DIP switch settings required (1=Off, 2=On, 3=On).
Warm-up Period: Upon installation or after power outages of 5 minutes or more, the sensor enters a warm-up period (30-60 seconds) during which the load turns ON. If no detection occurs within 1 minute, the load turns off. If occupancy is detected, the load remains ON until the space is vacated and the time delay elapses.
LED Indicators: Enabled by default, providing visual feedback on sensor activity.

Maintenance Features (Troubleshooting):

The guide provides a comprehensive troubleshooting section for common issues:

Lights do not turn on when entering the room:
- Check circuit breaker, sensor, and power pack wire connections.
- Verify 24VDC input to the sensor.
- Ensure the sensor is out of its warm-up period.
- Check PIR sensitivity setting (DIP switch #8).
- Adjust ultrasonic sensitivity if the green LED does not flash with movement.
- If the green LED is continuously on, adjust the ultrasonic sensitivity trimpot clockwise until it flashes only with movement.
- If red and green LEDs flash, check all sensor and power pack connections, and verify Light Level functionality if connected. Check for 24VDC at the power pack.
Lights do not turn off automatically:
- Reduce ultrasonic sensitivity by turning the adjustment pot counter-clockwise.
- Check if a Manual Switch connection is being used incorrectly.
- Reduce PIR sensitivity by turning DIP switch 8 to the off position.
- Check all sensor and power pack wire connections.
- Disconnect the power pack blue wire to isolate the problem between the power pack, sensor, or wiring.
- Turn sensitivity and time delay to minimum, allow the sensor to time out, and then readjust.
- If issues persist after checking wiring, consider replacing the sensor.

Important Warnings:

Power Off: Always turn power off at the circuit breaker before installing power packs.
Mounting Restrictions: Do NOT mount a ceiling sensor above a suspended fixture. Use a ceiling/wall mount sensor mounted to the wall below the plane of the bottom of the fixture.
Hot Air Supply: Mount the sensor at least 6 feet away from any hot air supply to prevent false triggers.
Wiring Separation: Care should be taken to separate high voltage power from low voltage (Class 2) control wiring. All connections to the sensor are low voltage, Class 2.