Wednesday, June 19, 2013

Drywall Dust Problems with System Sensor Smoke Detector

If any packaged air conditioning units are run during the drywall installation phase of building construction to assist in the drying of joint compound, the fine dust created by sanding of those drywall joints may compromise the System Sensor smoke detector sensor heads within the duct housing. The 2D51 System Sensor Head in the InnovairFlex Duct Smoke Detector models D4120, D4120W and D4S may display a “maintenance” condition that will require replacement or cleaning of the sensing chambers on the smoke detector head. The “maintenance” condition will be indicated on the fire alarm control panel, on the sensor itself or power board of the duct smoke detector (the sensor LED will blink “red” every five seconds and the power board LED will blink “amber” every five seconds).

To avoid this condition, it is recommended that the System Sensor smoke detector heads be removed during the construction phase and replaced once construction is completed and the Certificate of Occupancy is issued. The sensor heads twist out for removal and twist in for insertion.

Below is an extracted image of the System Sensor duct smoke detector sensor head:


Cleaning the sensing chamber on the sensor head

If the System Sensor smoke detector heads are not removed during the construction phase and the sensor chamber becomes dirty causing a maintenance condition (it will not always be visible on the exterior black screen on the sensor head), the sensor head must be cleaned with compressed air. To clean the sensor head chamber, follow these step-by-step instructions see the video demonstration below:

1. Remove the System Sensor smoke detector head to be cleaned from the duct smoke detector housing by twisting it in a counterclockwise direction.
2. Remove the smoke sensor cover by pulling outward on each of the four removal tabs that hold the cover in place.
3. Vacuum the screen carefully without removing it. If further cleaning is required continue with Step 4. Otherwise, skip to Step 7.
4. Remove the chamber cover/screen assembly by pulling it straight out.
5. Use a vacuum cleaner or compressed air to remove dust and debris from the sensing chamber.
6. Reinstall the chamber cover/screen assembly by sliding the edge over the sensing chamber. Turn until it is firmly in place.
7. Replace the cover using the holes for the LEDs for alignment and then gently push it until it locks into place.
8. Reinstall the System Sensor smoke detector head in the duct smoke detector housing by aligning it in the housing and twisting it in a clockwise direction.

Note: Cleaning only the sensor head’s exterior black screen will not remove any drywall dust in the smoke sensing chamber.
Note: Should the System Sensor duct smoke detector remain in a “maintenance” condition after cleaning, then it may require the complete replacement of the sensor head. The replacement sensor head is model 2D51.