Critical Environment Technologies CGAS-A-VLT-NH3-S Istruzioni per l'installazione e il funzionamento
cGas Ammonia Vent Line Transmitter - Addendum Rev. B | 2022.09
2 © 2022 All rights reserved. Data subject to change without notice.
IMPORTANT INFORMATION
The cGas Ammonia Vent Line Gas Detector is either a CGAS-A (analog) or a CGAS-D (digital)
Gas Detector that has been physically modied to mount on a vent line stack. How it
operates is the same as its corresponding base model, the CGAS-A or CGAS-D Gas Detector.
This document is an addendum and contains specic information for the installation and
calibration of the cGas Ammonia Vent Line Detector models.
For more information on wiring connections, wire gauge and run length, refer to the CGAS-A
Installation Manual or the CGAS-D Installation Manual
Refer to the cGas Detector Operation Manual for information on:
• Policies
• Warranty
• Copyrights
• Basic Operation and Instrument Settings
• Display Settings
• Alarm Status and Fault Settings
• Alarm Setpoints
• Enable/Disable Channel
• Relay Operation
• Test Functions
• Modbus and BacNet Conguration (digital model)
cGas Ammonia Vent Line Detector Part Numbers:
• CGAS-A-VLT-NH3-S
• CGAS-D-VLT-NH3-S
INSTRUMENT SERIAL NUMBER:
______________________________________________________
PURCHASE DATE:
______________________________________________________
PURCHASED FROM:
______________________________________________________
If you have questions, comments or require more information, please contact us at:
Critical Environment Technologies Canada Inc.
Unit 145, 7391 Vantage Way, Delta, BC, V4G 1M3, Canada
Toll Free: +1.877.940.8741
Telephone: +1.604.940.8741
Website: www.critical-environment.com
Rev. B | 2022.09 cGas Ammonia Vent Line Transmitter - Addendum
© 2022 All rights reserved. Data subject to change without notice. 3
TABLE OF CONTENTS
1 INTRODUCTION ................................................................................................. 4
1.1 General Description..................................................................................................................4
1.2 Key Features..............................................................................................................................4
2 INSTRUMENT SPECIFICATIONS........................................................................ 5
2.1 Technical Specications .........................................................................................................5
2.2 Enclosure Dimensions............................................................................................................. 7
2.3 Exterior Enclosure - Front .......................................................................................................8
2.4 Exterior Enclosure - Back........................................................................................................9
2.5 Interior Enclosure .....................................................................................................................9
3 SENSOR SPECIFICATIONS AND CONSIDERATIONS........................................ 10
4 INSTALLATION ................................................................................................ 11
5 CALIBRATION .................................................................................................. 11
5.1 Remove Detector from Vent Stack .....................................................................................12
5.2 Set Calibration Gas Value .....................................................................................................13
5.3 Attach Calibration Adapter with Tubing .............................................................................13
5.4 Zero (Null) Calibration............................................................................................................14
5.5 Span Calibration .....................................................................................................................14
5.6 Troubleshooting Calibration.................................................................................................15
5.3.1 Calibration Adapter Plug Doesn’t Fit ......................................................................16
5.3.2 Zero Fault ....................................................................................................................16
5.3.3 Span Fault ...................................................................................................................16
5.3.4 Zero Override..............................................................................................................16
5.3.5 Span Override .............................................................................................................16
6 SENSOR REPLACEMENT ................................................................................. 16
7 MAINTENANCE................................................................................................ 18
8 TROUBLESHOOTING........................................................................................ 18
cGas Ammonia Vent Line Transmitter - Addendum Rev. B | 2022.09
4 © 2022 All rights reserved. Data subject to change without notice.
1 INTRODUCTION
1.1 General Description
The cGas Ammonia Vent Line Detector is designed for continuous monitoring of ammonia
levels in the vent line of refrigeration systems, including the detection of equipment failure in
ammonia plant vent stack applications.
Using a a ¾” cast steel coupler, the cGas Ammonia Vent Line Detector is to be mounted
indoors on the ammonia vent relief stack above the pressure relief valve.
IMPORTANT: The cGas Ammonia Vent Line Detector is NOT designed to monitor ammonia
in applications requiring human health safety levels detection and is not designed to protect
people from toxic gas concentrations. The lowest reading the sensor will detect is above the
recommended exposure limit to ammonia.
NOTE: CET manufactures other ammonia gas detectors that meet human health safety
levels, if that is the required application. If you have any questions, please do not hesitate to
contact our service department for technical support.
This product must be installed by a qualied electrician or factory trained technician and
according to instructions indicated in this manual. This instrument should be inspected and
calibrated regularly by a qualied and trained technician.
This instrument has not been designed to be intrinsically safe. For your safety, do not use it
in classied hazardous areas (explosion-rated environments).
The cGas Ammonia Vent Line Detector is not intended for use in hazardous rated areas.
If after reading through the manual, you have any questions, please do not hesitate to
contact our service department for technical support.
1.2 Key Features
• Single channel, internal catalytic Ammonia sensor
• 4-20 mA output (CGAS-A-VLT model)
• Field congurable BACnet® MS/TP RS-485 or Modbus® RTU RS-485 digital output
signal (CGAS-D-VLT model)
• 24 VDC or VAC power (ground referenced)
• Easy Plug & Play Smart Sensor replacement at end of life, comes pre-calibrated
• Bright LCD display
• USB port for conguration changes and rmware upgrades
• 1 optional 2A SPDT dry contact relay (Option -RLY)
• Optional low temperature operation package (Option -LT)
• Standard water / dust tight, corrosion resistant enclosure (drip proof)
• Thermal resetting fuses
• RoHS compliant circuit board
Rev. B | 2022.09 cGas Ammonia Vent Line Transmitter - Addendum
© 2022 All rights reserved. Data subject to change without notice. 5
2 INSTRUMENT SPECIFICATIONS
2.1 Technical Specications
SENSOR
Sensor Type Catalytic
Gas Type Ammonia (NH3)
Range 0 - 3.00% volume range
Measures to 2 decimal places, tolerant to 17% volume
Response Time T90 < 30 seconds
MECHANICAL
Enclosure ABS / Polycarbonate, IP54 rating with splash guard installed.
Copper coated interior to reduce RF interference.
Weight 825 g / 29 oz
Size
Detector with splash guard:
127 x 127 x 84 mm / 5.0 x 5.0 x 3.3 in
Completely assembled product:
127 x 127 x 182.5 mm / 5.0 x 5.0 x 7.18 in
Coupler 19.5 mm / 3/4 inch NPT, cast steel
Sensor Assembly Length
(including coupler) 98.5 mm / 3.875 inches
Conduit Entry Points 12.7 mm / 1/2 in diameter
Mounting Holes 4.47 mm / 0.175 in diameter
maximum head diameter 8 mm / 0.32 in, #8 or 4 mm screw
USER INTERFACE
Display (standard) 2-line by 16-character graphic LCD, user congurable to
suppress reading display
Display (low temp) 2-line by 16-character OLED display for low temperature
applications (with Option -LT)
USB Port Internal port for USB memory stick connection for eld
conguration/rmware upgrades
Push Buttons Initiate calibration and menu options with internal UP, DOWN
and ENTER push buttons
Audible Alarm none
cGas Ammonia Vent Line Transmitter - Addendum Rev. B | 2022.09
6 © 2022 All rights reserved. Data subject to change without notice.
ELECTRICAL
Power Requirement
16 - 30 VDC, 3 W, Class 2
12 - 27 VAC, 50-60 Hz, 3 VA, Class 2
24V recommended. Refer to Section 6.7 Wiring Connections
Wiring
CGAS-A-VLT model
VDC (or ground referenced AC): 3-conductor 18 AWG (or
larger) shielded, stranded within conduit
VAC 4-conductor shielded 18 AWG stranded within conduit
Wiring
CGAS-D-VLT model
VDC or VAC (ground referenced) 4-conductor shielded 16 AWG
stranded within conduit, network wiring (daisy-chain)
Fuses Automatic resetting thermal
INPUT/OUTPUT
Analog Output
CGAS-A-VLT model One Linear 4 - 20 mA output, signals gas reading
RH & Temperature
(Option -RHT)
User selectable units (oC or oF) with user selectable display or
hide readings
Digital Output
CGAS-D-VLT model
User congurable in the eld, BACnet® MS/TP (version 1 rev
14) RS-485 or Modbus® RTU (version 1.1b3) RS-485
Relay (Option -RLY) Optional SPDT dry contact relay, rated 30 volts @ 2 amps
ENVIRONMENTAL
Operating Temperature 0°C to 40°C / 32°F to 104°F (standard)
-40°C to 40°C / -40°F to 104°F (with Option -LT)
Operating Humidity 15 - 90% RH non-condensing
Pollution Degree Degree 2
Altitude below 2,000 m
CERTIFICATION
Model: CGAS-A-VLT-NH3-S or CGAS-D-VLT-NH3-S
S/N: CGASA1807B00010
Rating: 16-30 VDC, 3W, Class 2
12-27 VAC, 50-60 Hz, 3VA, Class 2
CERTIFIED FOR ELECTRIC SHOCK & ELECTRICAL FIRE HAZARD ONLY. LA CERTIFICATION
ACNOR COUVRE UNIQUEMENT LES RISQUES DE CHOC ELECTRIQUE ET D’INCENDIE
D’ORIGINE ELECTRIQUE.
Rev. B | 2022.09 cGas Ammonia Vent Line Transmitter - Addendum
© 2022 All rights reserved. Data subject to change without notice. 7
Conforms to: CSA-C22.2 No. 205-12, UL508 (Edition 18):2018
Conforms to: EMC Directive 2014/30/EU, EN 50270:2015, Type 1, EN61010
Conforms to: FCC. This device complies with part 15 of the FCC Rules, Operation is subject
to the following two conditions: (1) This device may not cause harmful interference, and (2)
this device must accept any interference received, including interference that may cause
undesired operation.
2.2 Enclosure Dimensions
cGas Ammonia Vent Line Transmitter - Addendum Rev. B | 2022.09
8 © 2022 All rights reserved. Data subject to change without notice.
The area required for enclosure door to be open 90 degrees is 178 mm / 7.0 in or 254 mm /
10.0 in for fully open. With the optional splash guard installed, the enclosure is IP54 rated.
2.3 Exterior Enclosure - Front
NUMBER FEATURE FUNCTION
Door Hinge Secures door to base and allows easy
opening and closing
Display LCD display (standard display shown)
Splash Guard Covers unused sensor vent, protects
from water/dust ingress, IP45 rated
Door Screw Secures door shut
Lock Slot For security padlock or tie
13mm / 1.5 in water tight
cable restraint
Water tight conduit entry for shielded
18 awg stranded cable. For outdoor
applications, weather proof and UV
protected cable is suggested.
Rev. B | 2022.09 cGas Ammonia Vent Line Transmitter - Addendum
© 2022 All rights reserved. Data subject to change without notice. 9
2.4 Exterior Enclosure - Back
The sensor is potted into a 5 cm / 2 in long pipe tting that protrudes from the back of the
enclosure.
NUMBER FEATURE
5 cm / 2in pipe with potted sensor, screws into the cast steel mounting
plate
Cast steel sensor mounting plate
19 mm / 3/4 in cast steel coupler for connecting to mounting pipe
13 mm / 1/2 in water tight cable restraint. If using conduit, replace with
liquid tight type conduit tting.
2.5 Interior Enclosure
The sensor is potted behind the enclosure and wires pass from the back of the enclosure
into the interior of the enclosure and connect to a smart board that is plugged into the main
board.
cGas Ammonia Vent Line Transmitter - Addendum Rev. B | 2022.09
10 © 2022 All rights reserved. Data subject to change without notice.
Be careful not to trap the wire outside the enclosure when closing the door.
3 SENSOR SPECIFICATIONS AND CONSIDERATIONS
The cGas Ammonia Vent Line Detector comes with a catalytic ammonia sensor potted inside
the 5cm / 2 in long pipe tting that protrudes from the back of the enclosure.
The ammonia sensor has a standard measurement range of 0 - 3.00% vol or 0 - 30,000 ppm.
The ammonia sensor has a lifespan of approximately 2 to 3 years in air. Exposure to very
high concentrations of ammonia (>17 %vol) should be avoided. A large release of a high
concentration of ammonia may burn out the sensor and it will need to be replaced.
If you install and power up the cGas Ammonia Vent Line Detector as soon as it arrives, the
sensor will require about a 5 minute warm up period. The sensor goes through a burn in
period at our factory so it is ready for operation upon arrival. If the device is not installed
within two weeks of delivery, the sensor may require a longer warm up time to stabilize and
provide accurate readings (approximately 48 hours).
During calibration, when owing span gas on an ammonia sensor, if the reading climbs
higher than the calibration point after applying gas for 3 minutes, use that reading as the
calibration point.
Silicone, lead and chlorinated hydrocarbon vapours can poison catalytic sensors.
Temperature affects calibration. It is important to ensure the gas is at the appropriate
temperature during calibration. If the sensor is being used in an extreme temperature range,
calibration should be done in that same temperature range.
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