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GG-NH3
General Description
Installation
The GG-NH3 sensor is a +24 VDC, three-wire, 4/20 mA
sensor for ammonia which utilizes proven electro-
chemcial sensor technology for fast and accurate leak
detection. The standard detection range of the GG-
NH3 sensor provides real-time continuous monitoring
of ammonia concentrations accurately down to 5
ppm without false alarms. CTI typically recommends
a 0/100 ppm range for all personnel and product
protection areas. Higher ranges (0/250, 0/500, 0/1000)
are optional for higher alarm setpoint areas such as
Engine Rooms.
The GG-NH3 sensor provides an industrial standard
linear 4/20 mA output signal compatible with most gas
detection systems and PLCs.
This sensor is equipped with SafeCell technology
which checks the electrical viability of the
electrochemical cell every 40 seconds. If it is
determined that the cell is not electrically viable or
missing, the fault (red) LED will blink once per second.
After 6 hours of continued and consecutive test
failures, the 4-20 mA signal output will drop to 0.5 mA
and the fault LED stays on solid. This signal should be
interpreted as a sensor fault at the control panel and
prompt notification to plant personnel to investigate
the sensor. Typically, the cell will need to be replaced
once the SafeCell fault has occurred. Once the cell is
replaced or found to be electrically viable, the fault
condition will clear within 10 seconds.
Locating the sensor
One of the most important considerations when
installing the GG-NH3 sensor is that it must be easily
accessible for calibration and maintenance.
For optimum personnel protection (representative
concentration reading that an employee would be
exposed to), mount the sensor at a height in the
breathing zone of the employees. It would typically
be about five feet off the ground, which also allows
easy access. As a general rule of thumb, try to mount
sensors within 30 feet of potential leak sources.
Caution: Remove protective label
The GG-NH3 sensor is shipped with a yellow
label installed over the gas diffusion port of the
electrochemical cell to preserve cell life. The cell will
not detect ammonia vapors with this label installed.
Remove label and discard during installation.
