Critical Environment Technologies CGAS-A-VLT-NH3-S Installation and operating instructions

www.critical-environment.com
cGas Detector
Ammonia Vent Line Transmitter
Rev. B | 2022.09
Addendum
for cGas Detector Operation Manual

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 modied 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 specic 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 Conguration (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: [phone]
Email: [email protected]
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 Specications .........................................................................................................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 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).
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 congurable 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 conguration 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 Specications
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 congurable 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
conguration/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 congurable 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
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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
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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.

Rev. B | 2022.09 cGas Ammonia Vent Line Transmitter - Addendum
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4 INSTALLATION
The cGas Ammonia Vent Line Detector is intended to be permanently mounted indoors on
the ammonia vent relief stack above the pressure relief valve.
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.
The cGas Ammonia Vent Line Detector should be installed on the vent stack pipe using the
cast steel coupler, no more than 0.3 to 0.6 m / 1 to 2 ft from the discharge stack.
The bottom conduit entry point on the enclosure has been tted with a 12.7 mm / ½ in
water tight cable restraint. If conduit is being used, replace the cable restraint with a liquid
tight type conduit tting. 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.
If the transmitter must be installed outdoors, it is suggested to use weather proof and UV
protected cable and additional housing to protect it from the elements and low temperatures.
The factory installed splash guard that covers the (unused) sensor vent in the front of the
enclosure protects the device from water and dust ingress. Any water or physical damage
to the transmitter that occurs from the installer drilling installation holes will not be covered
under warranty. If using, the conduit tting at the bottom of the enclosure, it must be the
liquid tight type.
FOR MORE INFORMATION ON INSTALLATION INCLUDING WIRING CONNECTIONS, WIRE
GAUGE AND RUN LENGTH REFER TO THE CGAS-A INSTALLATION MANUAL OR THE
CGAS-D INSTALLATION MANUAL.
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.
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.
5 CALIBRATION
The cGas Ammonia Vent Line Detector is an equipment protection device, not a life safety
device and should be calibrated every 6 months.
Calibrating the cGas Ammonia Vent Line Detector has 5 processes:
1. Remove Detector from Vent Stack
2. Set Calibration Gas Value
3. Attach Calibration Adapter and Tubing
4. Zero (Null) Calibration
5. Span Calibration

cGas Ammonia Vent Line Transmitter - Addendum Rev. B | 2022.09
12 © 2022 All rights reserved. Data subject to change without notice.
NOTE: A calibration label should be applied after every calibration to conrm work performed
and the date it was conrmed. If a controller is involved, the alarm set points should be
indicated on a label on the front door of the enclosure so anyone working in the environment
can be aware.
5.1 Remove Detector from Vent Stack
The cGas Ammonia Vent Line Detector must be removed from the vent stack in order to
calibrate the sensor.
On the back of the device, a long pipe tting is connected with a coupler to the mounting pipe
on the vent stack to secure the device in place. Unscrew the wide ring portion of the coupler
and carefully remove the device from the mounting pipe. Be careful to not handle the device
roughly resulting in disconnecting or loosening the wires.
IMPORTANT: The catalytic sensor is very susceptible to shock - when working with the
sensor do not hit it. Manually loosen then senso. When replacing the tting does not have
to be pressurized, so minimal tightness is all that is required.
sensor
unscrew coupler
careful not to disconnect or loosen
the wires
WARNING: When you remove the device, the vent stack will be exposed and ammonia
may leak into the air. Vent line systems should always be treated with extreme caution and
workers should assume a relief valve could release at any time. Take all necessary safety
precautions and follow industry standard practices and local regulations when calibrating the
cGas Ammonia Vent Line Detector.

Rev. B | 2022.09 cGas Ammonia Vent Line Transmitter - Addendum
© 2022 All rights reserved. Data subject to change without notice. 13
5.2 Set Calibration Gas Value
Check to make sure that the calibration gas value set in the transmitter matches the gas
concentration of the calibration gas you are using. How much gas the sensor detects is
directly related to the Calibration Gas setting and the actual concentration of calibration gas
used during calibration.
The factory default used to calibrate the cGas Ammonia Vent Line Detector prior to shipping
is 0.5 % vol (5000 ppm) air balance.
From the main display, press ENTER.
Enter passcode 3032 using the UP button and ENTER button.
Enter Password
3032
Press ENTER to access the Calibrate Menu.
Calibrate Menu
Press Enter
In the Selected Channel menu, conrm the desired channel is showing.
Selected Channel
NH3
Press the UP button to accept the displayed calibration gas value if it is correct. Or press
ENTER and change the value using the UP or DOWN buttons.
Calibration Gas
0.5% vol NH3
Calibration Gas
>0.5% vol NH3
When nished pressed ENTER and then ENTER again to conrm and ENTER to exit.
Conrm?
>0.5% vol
N
>Y
5.3 Attach Calibration Adapter with Tubing
The ammonia sensor is potted into a 5 cm / 2 in long pipe tting that protrudes from the
back of the enclosure.
Press the calibration adapter with an O-ring and two zeroing port plugs into the sensor
opening with the tubing attached.
(P/N: CET-7000-CAP)

cGas Ammonia Vent Line Transmitter - Addendum Rev. B | 2022.09
14 © 2022 All rights reserved. Data subject to change without notice.
Ammonia is a reactive gas and can adhere to surfaces which can reduce the amount of gas
that reaches the sensor. When calibrating an ammonia sensor use a length of tubing no
longer than 0.6 to 1 m / 2 to 3 ft. If a longer length is necessary, use Teon lined tubing to
ensure the correct concentration of gas reaches the sensor.
5.4 Zero (Null) Calibration
Catalytic sensors require oxygen to work and thus the user MUST ow clean air or oxygen to
obtain a true zero.
NOTE: To exit the Zero Calibration at any time, press ENTER.
From the main display, press ENTER.
Enter passcode 3032 using the UP button and ENTER button.
Enter Password
3032
Press ENTER to access the Calibrate Menu.
Calibrate Menu
Press Enter
In the Selected Channel menu, conrm the desired channel is showing.
Selected Channel
NH3
Press the UP button to nd Calibrate Zero.
Calibrate Zero
100 AD
Press ENTER if using ambient air or attach the regulator to the cylinder of zero air, insert
the calibration adapter into the sensor opening on the front of the enclosure door (refer to
Section 6.3.1 Calibration Adapter Plug if the adapter will not t). Press ENTER to start the
Zero calibration. The display will show a countdown from 20 seconds.
Zeroing
47AD 18s
Zero Success
56AD
When the process has nished and the Zero calibration was accepted, press ENTER and use
the UP button navigate to Exit and press ENTER to exit. Remove the cylinder of zero gas. If
the Zero Calibration was not successful refer to Section 6.3.2 Zero Fault.
5.5 Span Calibration
Span calibration is owing a known concentration of the target gas over the sensor to adjust
the output signal to match the gas concentration. It resets the sensor’s electronic circuit
against a known concentration of target gas to correct drift and keep linearity.
Catalytic sensors require oxygen to work and thus the span gas must have “air” balance, not
N2 balance. The factory default used to calibrate the cGas Ammonia Vent Line Detector prior
to shipping is 0.5 % vol (5000 ppm) air balance.

Rev. B | 2022.09 cGas Ammonia Vent Line Transmitter - Addendum
© 2022 All rights reserved. Data subject to change without notice. 15
NOTE: To exit the Span Calibration at any time, press ENTER.
From the main display, press ENTER.
Enter passcode 3032 using the UP button and ENTER button.
Enter Password
3032
Press ENTER to access the Calibrate Menu.
Calibrate Menu
Press Enter
In the Selected Channel menu, conrm the desired channel is showing.
Selected Channel
NH3
Use the UP button to nd Calibrate Span. Press ENTER.
Calibrate Span
4000 AD
Conrm the span calibration gas level. It is important to make sure that the span gas level
value matches the calibration gas concentration you are using to calibrate the sensor. Press
ENTER to conrm value is correct. (If the value is not correct, press the UP button to move
the cursor to N and press ENTER. Change the cal gas level using the UP and ENTER buttons.)
Conrm CalGas
>0.5% vol
N
>Y
Press ENTER to conrm. Attach the regulator to the span gas cylinder and ow the span gas
over the sensor. You have 120 seconds to start owing the gas. If the gas isn’t detected, the
display will return to Calibrate Span.
Waiting for Gas
53AD 35s
When the gas is detected the display will show stabilizing for a countdown from 120 seconds
and then spanning for a countdown from 60 seconds.
Stabilizing
1961AD 82s
Spanning
1957AD 21s
Span Success
1956 AD 19
When the process has nished and the Span calibration was accepted, press ENTER and use
the UP button navigate to Exit and press ENTER to exit. Remove the cylinder of span gas. If
the Span calibration was not successful, refer to Section 6.3.3 Span Fault.
5.6 Trouble Shooting Calibration
This section is intended to aid in correcting issues that may arise during the calibration
procedure. If you are unable to correct a problem or you have questions, please contact our
Technical Service Department at [email protected] or 604-940-8741 (Local) or 1-877-940-
8741 (Toll Free).

cGas Ammonia Vent Line Transmitter - Addendum Rev. B | 2022.09
16 © 2022 All rights reserved. Data subject to change without notice.
5.6.1 Calibration Adapter Plug Doesn’t Fit
Use a slight twisting motion as you gently push the calibration adapter plug (p/n: CET-7000-
CAP) into the sensor opening. If it is hard to insert, moisten the O-ring seal slightly then try
re-inserting it.
5.6.2 Zero Fault
If the zeroing process fails, the cGas Detector will show a Zero fault. This will happen if the
ambient gas readings are at an unacceptable level due to not enough clean air - there is
enough residual target gas in the environment or other gases that are interfering with the
sensor seeing oxygen.
5.6.3 Span Fault
If the cGas shows a Span fault after trying to calibrate, it is possible that the sensor is dead
or the device isn’t seeing the gas (cylinder is empty, regulator or adapter plug is not attached
properly, tube is blocked, kinked, etc.).
Span Fault
197 AD 1 0s
Check all connections and possible interferences and try a complete calibration procedure
from the beginning again to see if this corrects the fault. If a second calibration does not
resolve the fault then the sensor needs to be replaced. Over time, a sensor degrades and
when it has gone beyond an acceptable level, it has reached its end of life and will no longer
pass a calibration. If replacing the sensor does not correct the fault, please contact Technical
Service at [email protected].
5.6.4 Zero Override
If the gas level (possible residual gas) is too high, but still within the override range, the
display will indicate that an override is required.
Override?
-?????
N
>Y
To override the value use the UP button to select Y and press ENTER. To keep the original
zero value, leave the indicator on N and press ENTER.
5.6.5 Span Override
During the Span calibration, readings are taken and from the results sensitivity is calculated
and compared to the original sensitivity of the sensor at the time of installation. If this
sensitivity is below the override range, but above the fault limit, the display will indicate that
an override is required. To override the value use the UP button to select Y and press ENTER.
To keep the original value, leave the indicator on N and press ENTER.
Override?
1953 AD 19
N
>Y
6 SENSOR REPLACEMENT
p/n: VLT-NH3-SEN
The catalytic ammonia sensor has a lifespan of approximately 2 to 3 years under normal
air conditions. The sensor may need replacing sooner if is is poisoned by exposure to a very
high concentration of ammonia.

Rev. B | 2022.09 cGas Ammonia Vent Line Transmitter - Addendum
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The replacement sensor comes potted in a 2” pipe with the wires attached to a Plug & Play
smart board that plugs into the main board.
The image in Section 4.3 Interior Enclosure shows the sensor installed.
NOTE: In order to remove the smart board from the interior of the enclosure, the transmitter
needs to be removed from vent stack. For instructions, see Section 5.1 Remove Detector
from Vent Stack.
Open the enclosure, remove the 3 screws connecting the smart board to the main board and
remove the smart board from the main board socket.
With the transmitter is free from the vent stack, unscrew the old sensor pipe from the back
of the transmitter and feed the old smart sensor board through the hole in the back of the
enclosure and remove the old assembly completely.
Feed the wires and new smart board through the hole in the back of the enclosure into the
interior of the transmitter and screw the new sensor pipe assembly into the back of the
transmitter and. Press smart board into the left side socket and replace the 3 screws.
IMPORTANT: The catalytic sensor is very susceptible to shock - when working with the
sensor do not hit it. Manually loosen then senso. When replacing the tting does not have
to be pressurized, so minimal tightness is all that is required.
Reattach the transmitter to the vent stack.
The replacement sensor comes pre-calibrated from the factory and should not require
calibration at the time of a replacement.
NOTE: Temperature affects calibration. If the sensor is being used in an extreme temperature
range, the sensor should be re-calibrated in that temperature range.
If the replacement sensor 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.

cGas Ammonia Vent Line Transmitter - Addendum Rev. B | 2022.09
18 © 2022 All rights reserved. Data subject to change without notice.
7 MAINTENANCE
There are no serviceable elements other than the calibration instructions outlined in this
manual. There are no replaceable components except the sensor.
The cGas Ammonia Vent Line Detector requires no assembly and very little maintenance.
The transmitter should be regularly inspected and monitored for possible damaging
conditions.
• If in a damp location, source of water should be shielded from continually contacting
the top of the transmitter. It is important to ensure that excess water and/or dust is
not somehow entering the enclosure and physically damaging the circuit board or
internal components.
• If painting is to be conducted in the transmitter’s location the transmitter needs to be
protected from over spray.
• If mounted outside in very cold temperatures (> -20°C / -4°F ), encasing the
transmitter in a suitable insulated box may be necessary
8 TROUBLESHOOTING
cGas Detector won’t power up. (blank display)
Is the power properly connected? Check the wiring connections. Refer to Wiring Connections
in the Installation Manual.
Display shows “SPAN FAULT” message.
Check all connections and possible interferences and try a complete calibration procedure
from the beginning again to see if this corrects the fault. If a second calibration does not
resolve the fault then the sensor needs to be replaced. Check to make sure the gas cylinder
isn’t empty.
Frequent, unexpected alarm signal sent to BAS/DDC.
Check to see if EMI and RF interference is causing the equipment to react this way. Refer to
EMI and RF Interference Considerations in the Installation Manual for more information.
Display shows “COMM” message. Modbus®or BACnet output signal has not been
connected properly; will also occur if no requests are being made from the controller to
the transmitter, ie addressing is not proper. Check the wiring connections and the network
settings.
Device cannot be seen by the Controller and/or the BAS / DDC on the Modbus® network.
Check the Baud rate. All devices in the network must have the same Baud rate.
• Check that local area network wiring is correct, especially the A and B lines to make sure they are not
swapped between devices on the network.
• Check the Modbus® ID. Each device must have a unique ID assigned to it.
Device cannot be seen by the Controller and/or the BAS / DDC on the BACnet® network.
• Check the Baud rate. All devices in the network must have the same Baud rate.
• Check to make sure the device has a unique ID assigned to it, the factory default is made up of the
MAC ID and the Base ID.

Rev. B | 2022.09 cGas Ammonia Vent Line Transmitter - Addendum
© 2022 All rights reserved. Data subject to change without notice. 19
• Check that local area network wiring is correct, especially the A and B lines to make sure they are not
swapped between devices on the network.
List of Possible cGas Error Codes:
(appears on the display in place of the units for a channel)
CODE DESCRIPTION
F01 Negative Fault Reading
Check to make sure the smart sensor board
is present and installed properly in the socket.
If installed, the cGas detects the sensor signal
is too far below its zeroAD. May be caused
by a sensor that is temperature or humidity
sensitive or the device wasn’t warmed up for
a minimum 24 hours. After appropriage warm
up period, zeroing the sensor will normally
resolve this.
F02 Smart Board Fault
cGas cannot communicate with the smart
board. Ensure the smart board is installed
and installed on the correct side (left) if a
single channel unit. Otherwise power cycle or
replace the sensor smart board.
F03 CO2 Communication Fault
cGas cannot communicate with the CO2
sensor even though it can communicate with
the smart board. Power cycle or replace the
sensor smart board.
F04 POT chip has failed The internal smart sensor board gainPOT chip has failed. If a power cycle does not
resolve this, replace the sensor smart board.
F05 Error in reading Smart Board cGas detected an error in the smart board ID. Use “Write to Sensor” for the indicated
channel (passcode 3022).
FO6 SB ID Mismatch Firmware expected a different smart board
than what is in the sensor socket.
FO7 RH & Temp Fault
cGas cannot communicate with the sensor.
Ensure the smart board is installed correctly.
If unresolved, contact our Technical Support
Department
FO8 DAC COMM This is a hardware fault. Contact our
Technical Support Department.
F20 RLY GPIO chip is not
responding
Check to make sure the relay board is
present and installed properly in the
socket. If installed, main board is unable to
communicate with the relay board and may
be damaged A replacement relay board may
be required.

© 2022 Critical Environment Technologies Canada Inc. All rights reserved. Data in this publication may change without notice.
CGAS-VLT-20220902
Unit 145, 7391 Vantage Way, Delta, BC V4G 1M3 Canada
Tel: [phone] Toll Free: +1.877.940.8741
www.critical-enviroment.com
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