Critical Environment Technologies CGAS-A Series User manual

Rev. B | 2020.22
www.critical-environment.com
CGAS-A CO2Detector
Analog Transmitter
Installation & Operation Manual

2 © 2020 All rights reserved. Data subject to change without notice.
cGas Detector Analog Transmitter - Operation Manual Rev. B | 2020.07
TABLE OF CONTENTS
1 POLICIES .......................................................................................................5
1.1 Important Note....................................................................................... 5
1.2 Warranty Policy ...................................................................................... 6
1.3 Service Policy ......................................................................................... 6
1.4 Copyrights .............................................................................................. 7
1.5 Disclaimer............................................................................................... 7
1.6 Revisions ................................................................................................ 8
2 INTRODUCTION .............................................................................................9
2.1 General Description................................................................................ 9
2.2 Key Features........................................................................................... 9
3 INSTRUMENT SPECIFICATIONS..................................................................10
3.1 Technical Specications...................................................................... 10
3.2 Enclosure Dimensions......................................................................... 13
4 SENSOR SPECIFICATIONS ..........................................................................13
4.1 Available Internal Gas Sensors ........................................................... 13
4.2 Optional RH & Temperature Sensor (Option -RHT) ............................ 14
5 INSTRUMENT FEATURES ............................................................................14
5.1 Exterior Enclosure................................................................................ 14
5.2 Interior System Layout......................................................................... 15
6 INSTALLATION ............................................................................................16
6.1 General Safety Warnings ..................................................................... 17
6.2 Protection Against Electrical Risks..................................................... 17
6.3 Protection Against Mechanical Risks................................................. 17
6.4 Mounting the Transmitter.................................................................... 18
6.4.1 Wet Environment Considerations ................................................ 19

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6.4.2 EMI and RF Interference Considerations ................................... 19
6.4.3 Mounting Height.............................................................................. 20
6.5 Enclosure Mounting Components ...................................................... 20
6.5.1 Enclosure Base................................................................................ 20
6.5.2 Enclosure Bottom ........................................................................... 21
6.6 Wiring Connections.............................................................................. 21
6.6.1 Analog Wire Gauge vs Run Length.............................................. 23
7 SYSTEM OPERATION...................................................................................24
7.1 Power-up and Warm-up Process from Factory.................................. 24
7.2 Navigating the Menu Structure ........................................................... 25
7.3 Accessing the Menu with Passcodes................................................. 25
7.4 Display Settings.................................................................................... 27
7.4.1 Adjust Display Brightness ............................................................. 27
7.4.2 Display Information - Normal or Minimal................................... 28
7.4.3 Display or Hide Gas Channel, RH + Temperature Readings ... 28
7.5 Alarm Status, Fault Detection and Communication Failure Alerts ... 29
7.6 Enable / Disable Channels................................................................... 30
7.7 Setting Channel Alarm Setpoints, Direction and Hysteresis ............. 31
7.8 Change Units (oC or oF) of Temperature Readings............................. 34
7.9 Temperature and / or Relative Humidity Offset ................................. 35
7.10 Set Analog Output Mode ................................................................... 36
7.11 Test Analog Output............................................................................ 37
8 PLUG & PLAY SMART SENSOR REPLACEMENT..........................................38
8.1 How to Install a Replacement Smart Sensor ..................................... 38
8.2 Read from Sensor ................................................................................ 39
8.3 Write to Sensor..................................................................................... 39
9 CALIBRATION ..............................................................................................40
9.1 Calibration Specications.................................................................... 40
9.1.1 Gas..................................................................................................... 40

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cGas Detector Analog Transmitter - Operation Manual Rev. B | 2020.07
9.1.2 Regulators & Flow........................................................................... 41
9.1.3 Adapters ........................................................................................... 41
9.1.4 Calibration Frequency .................................................................... 41
9.1.5 Gas Testing Frequency (Bump Testing) ..................................... 42
9.2 Calibrating the Internal Sensor............................................................ 42
9.2.1 Set Calibration Gas Value.............................................................. 42
9.2.2 Zero (Null) Calibration .................................................................... 43
9.2.3 Span Calibration.............................................................................. 44
9.3 Troubleshooting Zero and Span Calibration....................................... 45
9.3.1 Calibration Adapter Plug Doesn’t Fit ........................................... 46
9.3.2 Zero Fault.......................................................................................... 46
9.3.3 Span Fault......................................................................................... 46
9.3.4 Zero Override ................................................................................... 47
9.3.5 Span Override .................................................................................. 47
9.4 Calibrating the Analog Output (requires a 4-20 mA meter)............... 47
9.4.1 Set Analog Output Zero / Set Analog Output Range................ 48
10 ACCESSORIES ...........................................................................................49
10.1 Splash Guard (Option -S)................................................................... 49
10.2 Calibration Adapter Clip ”Cal Clip” .................................................... 49
10.3 Metal Protective Guard...................................................................... 50
10.4 Calibration Kit..................................................................................... 50
11 MAINTENANCE .........................................................................................51
12 TROUBLE SHOOTING.................................................................................52

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Rev. B | 2020.07 cGas Detector Analog Transmitter - Operation Manual
1 POLICIES
1.1 Important Note
Read and understand this manual prior to using this instrument. Carefully read
the warranty policy, service policy, notices, disclaimers and revisions on the
following pages.
This product must be installed by a qualied electrician or factory trained
technician and according to instructions indicated in this manual. This
instrument should be inspected and calibrated regularly by a qualied and
trained technician.
This instrument has not been designed to be intrinsically safe. For your safety,
do not use it in classied hazardous areas (explosion-rated environments).
INSTRUMENT SERIAL NUMBER:
______________________________________________________
PURCHASE DATE:
______________________________________________________
PURCHASED FROM:
______________________________________________________

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cGas Detector Analog Transmitter - Operation Manual Rev. B | 2020.07
1.2 Warranty Policy
Critical Environment Technologies Canada Inc. warrants the products we
manufacture (excluding sensors, battery packs, batteries, pumps, and lters)
to be free from defects in materials and workmanship for a period of two years
from the date of purchase from our facility. Sensors are consumable items and
once they leave our factory, we cannot reuse or resell them. As such, all sensor
sales are nal. Should the sensor itself be faulty, there is a one-year pro-rated
warranty that would apply from the date of purchase from our facility.
The warranty status may be affected if the instrument has not been used and
maintained as per the instructions in the manual or has been abused, damaged,
or modied in any way. The product is only to be used for the purposes stated
in the manual. Critical Environment Technologies is not liable for auxiliary
interfaced equipment or consequential damage.
Prior to shipping equipment to CETCI, contact our oce for an RMA #. All
returned goods, regardless of reason, must be accompanied with an RMA
number. Please read our Warranty and Returns Policy and follow our RMA
Instructions and Form.
Due to ongoing research, development, and product testing, the manufacturer
reserves the right to change specications without notice. The information
contained herein is based on data considered accurate. However, no warranty is
expressed or implied regarding the accuracy of this data.
1.3 Service Policy
CETCI maintains an instrument service facility at the factory. Some CETCI
distributors / agents may also have repair facilities; however, CETCI assumes
no liability for service performed by anyone other than CETCI personnel.
Repairs are warranted for 90 days after date of shipment (sensors have
individual warranties). Should your instrument require non-warranty repair, you

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Rev. B | 2020.07 cGas Detector Analog Transmitter - Operation Manual
may contact the distributor from whom it was purchased or you may contact
CETCI directly.
Prior to shipping equipment to CETCI, contact our oce for an RMA #. All
returned goods, regardless of reason, must be accompanied with an RMA
number. Please read our Warranty and Returns Policy and follow our RMA
Instructions and Form.
If the product is deemed repairable, for liability reasons, CETCI will perform all
necessary repairs to restore the instrument to its full operating condition.
1.4 Copyrights
This manual is subject to copyright protection; all rights are reserved. Under
international and domestic copyright laws, this manual may not be copied or
translated, in whole or in part, in any manner or format, without the written
permission of CETCI.
Modbus® is a registered trademark of Gould Inc. Corporation.
BACnet® is a registered trademark of American Society of Heating,
Refrigeration and Air Conditioning (ASHRAE).
1.5 Disclaimer
Under no circumstances will CETCI be liable for any claims, losses or damages
resulting from or arising out of the repair or modication of this equipment
by a party other than CETCI service technicians, or by operation or use of the
equipment other than in accordance with the printed instructions contained
within this manual or if the equipment has been improperly maintained or
subjected to neglect or accident. Any of the forgoing will void the warranty.
Under most local electrical codes, low voltage wires cannot be run within the
same conduit as line voltage wires. It is CETCI policy that all wiring of our

8 © 2020 All rights reserved. Data subject to change without notice.
cGas Detector Analog Transmitter - Operation Manual Rev. B | 2020.07
products meet this requiremen and all wiring be within properly grounded (earth
or safety) conduit.
1.6 Revisions
This manual was written and published by CETCI. The manufacturer makes
no warranty or representation, expressed or implied including any warranty of
merchantability or tness for purpose, with respect to this manual.
All information contained in this manual is believed to be true and accurate at
the time of printing. However, as part of its continuing efforts to improve its
products and their documentation, the manufacturer reserves the right to make
changes at any time without notice. In addition, due to improvements made to
our products, there may be information in this manual that does not exist in the
version of the product the user has. Should you detect any error or omission
in this manual, or should you want to inquire regarding upgrading the device’s
rmware, please contact CETCI at the following address:
Critical Environment Technologies Canada Inc.
Unit 145, 7391 Vantage Way, Delta, BC, V4G 1M3, Canada
Toll Free: +1.877.940.8741
Telephone: [phone]
Fax: [phone]
Email: [email protected]
Website: www.critical-environment.com
In no event will CETCI, its ocers or employees be liable for any direct, special,
incidental or consequential damages resulting from any defect in any manual,
even if advised of the possibility of such damages.

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Rev. B | 2020.07 cGas Detector Analog Transmitter - Operation Manual
2 INTRODUCTION
2.1 General Description
Thank you for purchasing our cGas Detector Analog Transmitter, a single
channel CO2 gas detection designed for use in non-explosion rated, commercial
applications that require continuous monitoring of Carbon dioxide. It offers one
4-20 mA analog output and is ideal for applications where compressed CO2is
used and stored, climate control in commercial buildings and other processes
requiring the continuous monitoring of CO2.
The sensors utilized in this device are accurate enough to measure to
Occupational Health & Safety (OHS) hazardous levels for toxic gases. The
transmitter operates by diffusion.
2.2 Key Features
• Single channel, single gas CO2
• 4 - 20mA analog output (signals gas reading)
• Easy Plug & Play Smart sensor replacement at end of life
• Pre-calibrated replacement sensors
• 3-wire VDC or 4-wire VAC power, 24 volt DC or AC power (nominal)
• In eld upgradable rmware/conguration via USB connection
• Bright LCD display
• Option -RHT: Relative Humidity and Temperature sensor (for display only)
• Option -S: Splash guard, factory installed, IP54 rated enclosure
• Standard water / dust tight, corrosion resistant enclosure (drip proof)
• Copper coated interior to reduce RF interference
• RoHS compliant circuit boards
• Auto resetting fuse

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cGas Detector Analog Transmitter - Operation Manual Rev. B | 2020.07
If after reading through the manual, you have any questions, please do not
hesitate to contact our service department for technical support.
3 INSTRUMENT SPECIFICATIONS
3.1 Technical Specications
MECHANICAL
Enclosure
ABS / Polycarbonate, IP54 rating with splash guard
installed. Copper coated interior to reduce RF
interference.
Weight 400 g / 14 oz
Size 127 mm x 127 mm x 71 mm / 5.0 in x 5.0 in x 2.8 in
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 congurable
to suppress reading display
USB Port Internal port for USB memory stick connection for
eld conguration/rmware upgrades
Push Buttons Initiate calibration and menu options with internal UP,
DOWN and ENTER push buttons
Audible Alarm none

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Rev. B | 2020.07 cGas Detector Analog Transmitter - Operation Manual
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 6.6 Wiring
Connections
Wiring 24 VDC or 24 VAC (ground referenced) 3-conductor
shielded 18 AWG (or larger) stranded within conduit
Fuses Automatic resetting thermal
INPUT/OUTPUT
Analog Output One Linear 4 - 20 mA output, signals gas reading
RH & Temperature
(Option -RHT)
User selectable units, user selectable display or
hide readings on the display, user selectable analog
output (default is the gas reading)
ENVIRONMENTAL
Operating
Temperature 0°C to 40°C / 32°F to 104°F (standard)
Operating Humidity 15 - 90% RH non-condensing
Pollution Degree Degree 2
Altitude below 2,000 m

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cGas Detector Analog Transmitter - Operation Manual Rev. B | 2020.07
CERTIFICATION
Model: CGAS-A-XXX
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.
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.

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3.2 Enclosure Dimensions
4 SENSOR SPECIFICATIONS
4.1 Available Internal Gas Sensors
Infrared Sensors Part Numbers Range Lifespan
Carbon Dioxide
(CO2)
CGAS-A-CO2-5K 0 - 5,000
ppm ~ 8 years
CGAS-A-CO2-5% 0 - 5% vol

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cGas Detector Analog Transmitter - Operation Manual Rev. B | 2020.07
4.2 RH & Temperature Sensor (Option -RHT)
The CGAS-A is a single channel device, it has one analog output. Therefore, if it
has an internal gas sensor and a relative humidity and temperature sensor, the
analog output signal be used to send the gas reading signal to a controller or
BAS/DDC. Therefore the RH & temperature readings are for display purposes
only, there is no current output or communication back to a controller or BAS/
DDC for RH or temperature readings.
5 INSTRUMENT FEATURES
5.1 Exterior Enclosure






NUMBER FEATURE FUNCTION
Door Hinge Secures door to base and allows
easy opening and closing
Display LCD display (standard display
shown)

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Rev. B | 2020.07 cGas Detector Analog Transmitter - Operation Manual
Sensor Opening Allows gas diffusion into sensor
Door Screw Secures door shut
Lock Slot For security padlock or tie
5.2 Interior System Layout







NUMBER FEATURE FUNCTION
Programming
Buttons
Access menu options and program
functions using buttons inside the
enclosure. (Arrow up, Enter, Arrow down)
Test Points: TP1
& TP2 For measuring voltage output
TB1 Wiring
Terminal
Pluggable terminal for Power & signal
output
USB Connection For rmware and conguration upgrades

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cGas Detector Analog Transmitter - Operation Manual Rev. B | 2020.07
Sockets for smart
sensor board
The CO2sensor board plugs into the main
board using these sockets
6 INSTALLATION
The CO2sensor in the cGas Detector goes through a burn in period at our
factory prior to shipping so it is ready for operation upon arrival. If you install the
cGas Detector when it arrives, the sensor will not require a long warm up period
(about 2 minutes).
NOTE: CETCI suggests that upon power-up, all sensors be left to warm up for
24 hours prior to considering the gas readings to be accurate.
If the device is not installed within two weeks of delivery, the sensor may
require a longer warm up time to stabilize (approximately 48 hours) and
provide accurate readings.
NOTE: All sensors are calibrated in the factory before they are shipped
and should not require calibration at the time of a routine installation or
replacement.
NOTE: 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.
A bump test will help you determine if a sensor requires calibration. If the
sensor still does not respond as it should after a successful calibration, it
probably requires replacing.

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Rev. B | 2020.07 cGas Detector Analog Transmitter - Operation Manual
6.1 General Safety Warnings
The cGas Detector is intended for indoor use, permanently mounted at a height
that is appropriate for the type of gas being monitored. Refer to Section 6.4
Mounting the Transmitter. The cGas Detector should be protected from extreme
weather conditions.
The cGas Detector requires no assembly and virtually no maintenance other
than regular calibration of the internal and/or remote sensors and ensuring
that excess water or dust not somehow entering the enclosure and physically
damaging the circuit board or internal components. There are no serviceable
elements other than the calibration instructions outlined in this manual. There
are no replaceable components except the sensors.
6.2 Protection Against Electrical Risks
Disconnect all power before servicing. There may be multiple power sources.
Power supply may have a building installed circuit breaker / switch that is
suitably located and easy to access when servicing is required and should be
labelled as cGas Detector supply (disconnecting power to the cGas Detector).
Appropriate markings should be visible at the circuit breaker / switch that is
supplying power to the cGas Detector.
This device may interfere with pacemakers. Modern pacemakers have built-in
features to protect them from most types of interference produced by other
electrical devices you might encounter in your daily routine. If you a have a
pacemaker, follow your healthcare provider’s instructions about being around
this type of equipment.
6.3 Protection Against Mechanical Risks
The door of the enclosure can be removed if absolutely necessary to facilitate
installation of the base but it is not recommended on this version. Extreme care

18 © 2020 All rights reserved. Data subject to change without notice.
cGas Detector Analog Transmitter - Operation Manual Rev. B | 2020.07
and caution must be exercised when removing the door to avoid damaging
the hinges. The door should only be removed when absolutely required. Any
damage occurring from door removal procedure will not be covered under
warranty.
If the unit is installed on a wall, open the enclosure fully, grasp the door,
keeping it open and being careful not to make contact with any of the internal
components (circuit board). If the base is not mounted, grasp the base with
your other hand. Tug on the door, pulling towards you making sure the door is
still open and straight. DO NOT TWIST. The section of the hinges located on the
base should “snap” apart from the part of the hinges located on the door.
After installation, place the door hinges over the installed base hinges, with the
unit fully open and push towards the wall. The hinges should easily “snap” back
into place.
The enclosure has one screw securing the door to the base for electrical safety
and provides an opening to allow the user to apply a padlock or tie wrap if they
desire the transmitter to be locked.
Be aware that the hinged door that could potentially pinch ngers and the sharp
edges and/or jumper pins on the board could potentially prick or cut ngers if
not handled carefully.
6.4 Mounting the Transmitter
The cGas Detector should be installed on a at vertical surface using the four
4.4 mm / 0.175 in diameter mounting holes provided to maintain water tight
status. Care should be taken to ensure that the face of the cGas Detector is
not obstructed in order to maximize the sensor’s exposure to the environment
being monitored.
Two ½ in / 12.7 mm conduit entry points are provided in the enclosure. Both
are located in the enclosure base. One in the rear of the base and one on the

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Rev. B | 2020.07 cGas Detector Analog Transmitter - Operation Manual
bottom edge of the base. Refer to Section 6.5 Enclosure Mounting Components.
The clearance from the PCA to the base enclosure is 12.7 mm / ½ in. Do not
use a conduit connector that has more than 12.7 mm (½ in) of thread length.
NOTE: When mounting the enclosure, allow enough room to allow the end user
to open the door fully to access the internal adjustments.
6.4.1 Wet Environment Considerations
If the cGas Detector is to be installed in a potential hose-down application or
any application whereby liquid could be directed towards the sensor opening,
the cGas Detector should be ordered with an optional attached splash guard
(factory installed).
If used in a wet or wash down application, the conduit hub entering the cGas
Detector enclosure must be liquid tight type. Any water or physical damage to
the transmitter that occurs from the installer drilling their own installation holes
will not be covered under warranty.
6.4.2 EMI and RF Interference Considerations
All electronic devices are susceptible to EMI (Electromagnetic Interference)
and RFI (Radio Frequency Interference). Our detectors have been designed
to reduce the effects of these interferences and we meet CSA FCC and CE
requirements for these type of devices. However there are still circumstances
and levels of interference that may cause our equipment to respond to these
interferences and cause them to react as if there has been gas detected.
There are some installation procedures that will reduce the likelihood of getting
faulty readings:
1. Locate the detectors and controllers out of the way from normal foot
trac and high energy equipment.
2. Conrm the devices are properly grounded using conduit and shielded
cabling.

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cGas Detector Analog Transmitter - Operation Manual Rev. B | 2020.07
3. Inform operators and technical staff working in the surrounding area
to be aware of these possible conditions and that two way radios,
Bluetooth enabled devices, cell phones and other electrical equipment
may interfere with the response of the gas detectors.
6.4.3 Mounting Height
The sensor mounting height depends on the molecular weight of the gas in
relation to the molecular weight of air. Carbon dioxide has a molecular weight
close to that of air and the sensor should be installed in the “breathing zone”.
The breathing zone refers to the area 4 - 6 f / 1.2 - 1.8 m from the nished oor.
This range is where most human breathing takes place.
6.5 Enclosure Mounting Components
6.5.1 Enclosure Base





 