InstallatIon sheet
521LX and 521LXT Addressable Smoke Detectors
Description
The Model 521LX and 521LXT Smoke Detectors are the industry’s finest smoke detectors, with analog features
such as remote maintenance reporting (CleanMe
™
), drift compensation, and multi-criteria detection. These smoke
detectors incorporate an addressable single-point module for connection to the Keypad bus or LX-Bus
™
of
XR100/XR500, and XR150/XR350/XR550 Series panels. The 521LXT also includes multi-criteria fast response heat
sensor algorithms for a broad range of fire detection.
Single Point Addressable
Incorporated is a factory mounted, addressable single-point zone expander on the back of the smoke detector. The
included 4-wire harness allows a direct connection to the Keypad bus or LX-Bus of XR100/XR500, and XR150/XR350/
XR550 Series panels. The integrated zone expander reports smoke detector alarm and service conditions to the panel
as a single zone. A TXD LED is also included, which flashes to confirm device polling.
CleanMe
™
Remote Maintenance/Trouble Reporting Feature
These detectors have a
unique feature that allows a
service signal to be sent to the panel when the smoke detector
has drifted outside UL sensitivity ranges or a hardware fault exists. In most cases, the signal is the result of the
detector becoming dirty over time and, as a result, has become oversensitive. This condition could result in a false
alarm. The CleanMe
™
signal enables the panel to receive a service signal allowing an installer time to clean the
detector by replacing the inexpensive optical chamber with a new DMP Model 525. This service information can be
transmitted to the central station.
Self-Diagnostics with Automatic Sensitivity Testing
Each photoelectric smoke detector monitors its own sen sitivity and operational status. Once a day, and immediately
upon first power up, the detector performs a full diagnostic test that includes a sensing chamber and internal
electronics dy namic test. If the detector drifts out of its sensitivity range or fails internal diagnostics, the alarm LED
flashes once every second to indicate trouble. This meets NFPA 72 field sensitivity testing requirements without the
need for external meters.
Built-In Drift Compensation
The detector is the industry’s first addressable smoke detector with built-in drift compensation. Automatically
adjusts sensitivity, up to a maximum of 1.0%/ft., as it becomes dirty. This feature increases immunity to dust and
dirt by 30 to 50%.
Installation
Consult the Local Authority Having Jurisdiction (AHJ) and NFPA 72 for specific installation information regarding
smoke detector spacing, placement, and special applications.
The detector wires directly to the panel 4-wire Keypad bus or LX-Bus. See
Compatible LX-Bus Interface Cards
.
When wired to the LX-Bus, the detector uses only one of the available expansion zone numbers allowing the
assignment of additional zone expanders to the next zone number address. See
Addressing the 521LX and LXT
.
Locking the Detector
Each detector head is equipped with a breakaway locking tab slot
to prevent unauthorized detector head removal. For installations
where unauthorized removal of the detector head is not a
concern, such as high ceilings, no action is required. Remove the
head by simply turning counterclockwise.
When the head must lock to the base, simply break away the
locking tab and the knock out for the screwdriver slot with a pair
of pliers. To remove the detector head, insert a small screw-
driver through the slot at the side of the base and press in while
simulta neously turning the detector head counterclockwise.
See Figure 1.
Installing the Mounting Base
The included mounting base makes the smoke detector easy to install and remove if necessary. The detector head
simply twists off of its 4.75” mounting base.
The mounting base connects directly to standard single-gang electri cal boxes, 3-inch round, or
4-inch octagonal boxes. The base may also be mounted without electrical boxes if approved
by the AHJ or if codes allow.
Figure 1: Locking Mount on 521LX/521LXT
To lock the 521 to the mounting
base, use pliers to break off the
locking tab on the base tab
and
the breakaway tab for the
screwdriver slot on the 521.
