4 Intelligent Products—DH500 Series Intelligent Air Duct Smoke Detector
A Heating, Ventilating, and Air Conditioning (HVAC) system supplies
conditioned air to virtually every area of a building. Smoke introduced
into this air duct system will be distributed to the entire building. Smoke
detectors designed for use in air duct systems are used to sense the presence
of smoke in the duct and initiate action to prevent the spread of smoke.
The DH500 series air duct detector housings are used with the intelligent
1551J ionization detector heads and 2551J photoelectronic detector heads.
These two smoke detection methods are combined with an efficient
housing design that samples air passing through a duct and allows early
detection of a developing hazardous condition. When sufficient smoke is
sensed, an alarm signal is initiated at the fire control panel monitoring the
detector, and appropriate action can be taken to shut off fans, blowers, and
change over air handling systems. This can prevent the distribution of
toxic smoke and fire gases throughout the areas served by the duct system.
There are two models of the duct smoke detector: the DH500J, which has
auxiliary relays that allow for optional fan control, alarms, etc. and
operates on 120/240 VAC or 24 VAC/DC; and the DH502J, which has no
auxiliary relays and operates on 24 VDC. Both models have two Form-C
alarm activated relay output contacts that are available for local control
purposes and two Light Emitting Diodes (LEDs) on each detector latch on
to provide a local alarm indication. Remote alarm indication is made
possible by utilizing the 12 volt alarm output to connect to the RA400Z
remote annunciator. By using the correct code commands from the fire
alarm control panel, the duct detector can be tested and the alarm can be
reset. See the panel instructions for details.
Table 1: Contents of the Duct Detector Housing Kit
Number
Item
1
Complete Housing Base and Cover Assembly
2
No. 10 Sheet Metal Mounting Screws
2
Sampling Tube Filters
1
Test Magnet
1
Drilling Template
2
5/16-in. O-rings
2
Foam Gaskets
4
No. 6 Self-tapping Mounting Screws for the Sampling Tube
1
Filter Adapter
1
Inlet Tube End Plug
2
No. 10 Speed Nuts
General
Description