Det-Tronics TXL Series Gas Transmitter - Manual (Page 10)

INSTALLATION
LOCATING THE GAS DETECTOR
Identifying potential leak sources and leak accumulation
areas is the first step in determining the best detector
mounting locations. In addition, identification of air cur-
rent/wind patterns within the protected area is useful in
predicting gas leak dispersion behavior, especially out-
doors. This information should be used to identify opti-
mum sensor installation points. The most effective num-
ber and placement of detectors varies depending on
the conditions at the job site. The individual designing
the installation must often rely on experience and com-
mon sense to determine the detector quantity and best
locations to adequately protect the area. Note that it is
typically advantageous to locate detectors where they
are accessible for maintenance, and also where the dig-
ital display can be easily seen. Locations near exces-
sive heat/vibration sources should be avoided if possi-
ble.
Final suitability of possible gas detector locations
should be verified by conducting a job site survey. Gas
detector area of coverage is a subjective evaluation,
and may require long-term empirical data to confirm
effectiveness. A typical rule of thumb is that one detec-
tor can cover a 900 square foot area. However, this rule
of thumb is subject to change depending upon specific
application properties and requirements.
NOTE
For intrinsically safe installations, only the TXL
detector can be located in a hazardous area. The
barrier and controller must be located in a non-
hazardous area.
MOUNTING REQUIREMENTS
The TXL Series is provided with built-in mounting holes
that will accept #8 x 1" mounting screws. The cover
must be removed from the TXL for access to the mount-
ing holes. See Figure 1. Always ensure that the mount-
ing surface is vibration-free and can suitably support
the total weight of the TXL detector without assistance
from electrical cabling or conduit system.
The TXL Series of gas detectors is classified intrinsically
safe for Class I, Division 1, Groups A, B, C, and D
atmospheres; and Class ll, Division 1, Groups E, F, G,
and Class lll areas when used with specified barrier.
Intrinsically safe approval was completed in 20.9% O
2
atmosphere only.
For Class I, Division 1 hazardous areas, the use of certi-
fied intrinsically safe cabling is recommended for use
with the TXL to ensure that all applicable hazardous
area installation requirements are fulfilled.
DEVICE MOUNTING ORIENTATION
It is recommended to always install the TXL Series gas
detector with the sensor pointing downward. While the
TXL is not position-sensitive in terms of sensor opera-
tion, the sensor protection hydrophobic filter will provide
optimum performance if the sensor is installed pointing
downward. Accumulation of contaminants on the sen-
sor may occur if the device is installed with the sensor
pointing upward or sideways.
DIGITAL DISPLAY VISIBILITY
It is recommended to select a mounting orientation
where the display is easily visible to personnel within the
area.
24 VDC POWER WIRING
Continuous, two-conductor stranded and shielded 20
AWG cable, such as Belden #8762 or # 9154 is recom-
mended for use with the TXL. Conduit is highly recom-
mended for improved shielding and cable protection.
Calculate the total system power consumption rate in
watts from cold start-up. Select a linear power supply
with adequate capability for the calculated load. Ensure
that the selected power supply provides regulated and
filtered 24 VDC output power for the entire system.
8 95-8541 1.1
4.056
(10.3)
2.366
(6.0)
A2127
Figure 1—Mounting Dimensions of the TXL Detector in Inches (CM)