TQ Environmental TQ122 User manual

TQ Environmental Ltd.
5812M16
Issue 16: 17th Feb 2022 Page 1 of 22
TQ122
GAS SENSOR HEAD
OPERATING MANUAL
©TQ Environmental Ltd.
This manual must not be copied or reproduced in part without the express written
permission of TQ Environmental Ltd. All information contained herein is subject to
modification.
TQ ENVIRONMENTAL Ltd BS EN ISO 9001
TQ Environmental Ltd,Silkwood Court, Wakefield, West Yorkshire, WF5 9TP. United Kingdom
Tel: +44 (0) 1924 271013 Email: sales@tqenv.com
Web: www.tqenv.com
ATEX

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CONTENTS
Page no:
Proprietary 3
Warning, Cautions and Notes 3
Safety Warnings 4
Limit of Application of Operating Manual 4
Section 1 Description
1.1 General Description 5
1.2 Method of Detection 5
1.3 Sensor Unit Description 5
1.4 Gases Monitored 6
1.5 Performance Specifications 8
1.6 Cross Sensitivity 9
1.7 Performance Tests 10
Section 2 Installation
2.1 Mechanical Installation 11
2.1.1 General 11
2.1.2 Guidelines 11
2.2 Electrical installation 11
2.2.1 Cabling 12
Section 3 Commissioning and Calibration
3.1 Commissioning 15
3.2 Calibration 15
Section 4 Maintenance
4.1 Routine Maintenance 17
4.2 Warranty 17
Section 5 Certification 18
ADDENDUM I Duct Mounting Kit 20

TQ Environmental Ltd.
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Issue 16: 17th Feb 2022 Page 3 of 22
PROPRIETARY
No part of the hardware or documentation may be reproduced, transmitted, transcribed,
stored in a retrieval system, or translated into any language or computer language, in any
form or by any means, without prior written permission of TQ Environmental LTD
While great efforts have been made to assure the accuracy and clarity of this document, TQ
Environmental LTD assumes no liability resulting from any omissions in this document, or
from misuse of the information obtained herein. The information in this document has been
carefully checked and is believed to be entirely reliable with all of the necessary information
included. TQ Environmental LTD reserves the right to make changes to any products
described herein to improve reliability, function, or design, and reserves the right to revise
this document and make changes from time to time in content hereof with no obligation to
notify any persons of revisions or changes. TQ Environmental LTD does not assume any
liability arising out of the application or any use of any product or circuit described herein;
neither does it convey license under its patent rights or the rights of others.
WARNINGS, CAUTIONS AND NOTES
Warnings identify an operating or maintenance procedure, practice,
condition, or statement that, if not strictly followed, could result in death
or injury to personnel.
Cautions, which appear elsewhere in this manual, identify an operating
or maintenance procedure, practice, condition, or statement that if not
strictly followed could result in equipment damage or serious impairment
of system operation.
Notes highlight certain operating or maintenance conditions or
statements that are essential but not of known hazardous nature as
indicated by Warnings and Cautions.
Warnings, Cautions and Notes are included throughout this manual, as
required. Additionally, this section contains important Warnings that
may not be contained elsewhere within this instruction manual.

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SAFETY WARNINGS
•TO MAINTAIN THE HAZARDOUS AREA CERTIFICATION FOR THE TQ122 GAS
SENSOR, IT MUST BE SCREWED INTO A SUITABLY CERTIFIED JUNCTION
BOX TO ALLOW CONNECTION TO THE ASSOCIATED CONTROL/DISPLAY
UNIT. NEITHER THE COVER OF THE TQ122 NOR THE ENCLOSURE INTO
WHICH THE SENSOR UNIT IS SCREWED MAY BE REMOVED UNLESS ALL
POWER TO IT HAS BEEN REMOVED OR THE AREA HAS BEEN TESTED AND
CERTIFIED TO BE FREE OF COMBUSTIBLE GAS AND THAT CONTINUOUS
MONITORING OF THE AREA IS PERFORMED BY SUITABLE INDEPENDENT
EQUIPMENT UNTIL THE COVERS ARE REPLACED.
•THIS TQ122 GAS SENSOR HAS BEEN CERTIFIED AS FLAMEPROOF FOR
NORMAL ATMOSPHERES ONLY. USE OF THIS SENSOR IN AN OXYGEN-
ENRICHED ATMOSPHERE IS NOT INCLUDED IN THIS CERTIFICATION.
•TO MAINTAIN THE HAZARDOUS AREA CERTIFICATION THE TQ122 MUST BE
USED IN ACCORDANCE WITH THE REQUIREMENTS GIVEN IN SECTION 5.
•FOR SAFETY REASONS, THE TQ122 GAS SENSOR MUST BE INSTALLED,
OPERATED AND SERVICED BY QUALIFIED PERSONNEL ONLY. READ AND
UNDERSTAND THIS INSTRUCTION MANUAL COMPLETELY BEFORE
OPERATING THE GAS SENSOR.
APPLICATION
THIS OPERATING MANUAL DESCRIBES THE INSTALLATION AND OPERATION OF
THE FOLLOWING SENSORS:-
122-001
Oxygen
Toxic Gases
122-002
Carbon Monoxide
122-003
Hydrogen Sulphide
122-004
Sulphur Dioxide
122-007
Nitric Oxide
122-017
Ethylene Dioxide
122-210
Methane based
122-211
Petrol vapour (n-pentane)
122-212
Ammonia
122-215
Hydrogen

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SECTION 1 - DESCRIPTION
1.1 GENERAL DESCRIPTION
The TQ122 series is a range of highly reliable gas sensors designed to give extended
service under extreme conditions. The sensor is specifically manufactured and calibrated
to detect the presence of the gas indicated on the body of the sensor. The sensors are
either 24v dc operation in 4-20mA current sink mode or form part of a “Wheatstone Bridge”.
With either type, the Control Unit must be capable of supplying the operating power,
handling the signal generated by the sensor, calculating and displaying the gas/vapour
concentration as well as generating any alarms required by the application.
The TQ122 Sensors are used for diffusion sensing applications. These are applications in
which the sensor continuously monitors that part of the environment with which it is in
contact, with the gas diffusing into the sensor’s active area. This technical manual covers
the use of the TQ122 Sensor as a diffusion type sensor. A suitable device may be connected
to the sensor to allow its use in flow through applications.
1.2 METHOD OF DETECTION.
The gas being monitored diffuses through the stainless steel membrane on the head of the
unit. This then passes into a cell where the gas of interest reacts chemically with a sensing
element housed within a secure unit inside the device. The chemical reaction generates a
voltage proportional to the concentration of the gas being monitored. In sensors providing a
current output an electronic circuit within the device provides a current output within the
range 4 to 20 mA. The current is proportional to the concentration of gas being measured.
In flammable gas sensors the gas is burned catalytically in the presence of oxygen
(pellistors) generating an “out of balance” signal from a Wheatstone Bridge arrangement.
The devices have a lifetime limited by a number of factors depending upon the gas being
monitored and the type of sensing element. Many of the chemical reactions taking place
within the cell will require the presence of oxygen in the gas being monitored.
1.3 SENSOR UNIT DESCRIPTION.
The fully assembled TQ122 Sensor unit (Figure 1) has the approximate dimensions of 70
mm long (including the M20 thread used to fasten the sensor to the junction box) x 50mm
diameter. The M20 thread is approximately 15mm long. A nylon washer and M20 nut are
provided for attaching to the junction box.
Two or three wires, approximately 190mm long, protrude from the potting on the unit to
allow connection to other cabling in the junction box.
A flame arrestor / diffusion device is provided on the head of the unit to allow the gas for
measurement to enter the device.

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A M30 x 2mm pitch thread is provided on the head to allow connection of a suitable flow
through device if required by the application. The thread is approximated 14mm deep.
SINTER
M20 MOUNTING POINT
ON JUNCTION BOX
2 OR 3 WIRES
TO JUNCTION BOX
CONNECTION PORT
FOR A "FLOW-THROUGH"
DEVICE.
FIGURE 1.---GENERAL OVERVIEW
1.4 GASES MONITORED.
A number of different types of sensing elements may be fitted to the TQ122 Gas Sensor
depending upon the gas being monitored and the composition of the background gas
present. Table 1 details the sensorsavailable. The measurement of toxic gases and oxygen
are 4-20mA based sensors (electrochemical cells) whilst, in the flammable gas sensors, the
gas is burnt catalytically in the presence of air (pellistors).

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Table 1. TQ122 Sensor Ranges
TQ PART NO
GAS/VAPOUR
RANGE
122-001
Oxygen
0 –25 %volume
Toxic Gases
122-002
Carbon Monoxide
0 –1000 ppm
122-003
Hydrogen Sulphide
0 –50 ppm
122-004
Sulphur Dioxide
0 –20 ppm
122-007
Nitric Oxide
0 –100 ppm
122 - 020 - 5000
Ammonia
0 –5000 ppm
122 - 213
Ammonia
0 –1000 ppm
122 –213 - 500
Ammonia
0 –500 ppm
122 - 214
Ammonia
0 –100 ppm
122-017
Ethylene Dioxide
0 –50 ppm
Flammable
Gases/Vapours
122-210
Methane based
0 –100 % LEL (5% volume)
122-211
Petrol vapour
(n-pentane)
0 –100 % LEL (1.4% volume)
122-212
Ammonia
0 –20 % LEL (3.0 % volume)
122-215
Hydrogen
0 –100 % LEL (4% volume)

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1.5 PERFORMANCE SPECIFICATIONS.
The performance of the TQ122 will depend upon the gas being monitored and the
background gas composition.
Table 2. TQ122 Sensor Performance Specifications.
FACTOR
SPECIFICATION
Detection Method:
Electrochemical, pellistor or similar cell
Sampling Method:
Continuous Diffusion (option of flow through cell)
Accuracy:
Application Dependent
Repeatability:
Application Dependent
Gas Temperature Range:
Pellistor -30C to +60C 1
Electrochemical -20C to +50C 1
Gas Pressure Range
+/- 200mm wg
Humidity Range:
0 - 99% Relative Humidity (Non-condensing)
Mean Time Between Failures:
Application Dependent
Operating Voltage:
24 Vdc
Output Current: (4-20mA
Sensors)
4 –20 mA into 600ohm max load.
Connections:
2 Wire or 3 wire
Construction Materials:
Flame Arrestor: 316 Sintered Stainless Steel
Body: 316 Stainless Steel
Weight:
540g (excluding junction box)
Electrical Hazardous Area
Certifications:
Ex db llC T5 Gb ( Ta= -20 to +40C)
Ex db llC T6 Gb ( Ta= -20 to +30C)
EN60079-0:2018+CORR1:2020 &
EN60079-1:2014+CORR1:2018
Shelf Life & Storage:
O2& Toxic:- 6 months, Flammable:-12months. All
must be stored at 0 –30 C in dry air (or nitrogen in
the case of O2).
1. In hazardous area applications the gas temperature range must be read in conjunction
with the maximum ambient temperature (Ta) assigned to the instrument.

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Table 3. Individual Sensor Performance
TQ PART NO
T90 RESPONSE
(sec) (max)
RESOLUTION
122-001
40
0.1% volume O2
Toxic Gases
122-002
30
10 ppm CO
122-003
50
1 ppm H2S
122-004
40
1 ppm SO2
122-007
30
1 ppm NO
122-017
30
1 ppm Ethylene Oxide
Flammable
Gases/Vapours
122-210
30
1 % LEL CH4
122-211
30
1 % LEL petrol
122-212
30
1 % LEL NH3
122-215
30
1 % LEL H2
The Response times are approximate and will depend upon configuration and sample
system. They are based upon a sensor fitted with a flow through cap, vented to
atmosphere and with gas flowing at 500 cm3/min.
1.6 CROSS-SENSITIVITY
Most electrochemical sensors and all pellistors are non-specific in the gas or vapour
monitored. The End-User must be satisfied that the sensor is “fit” for the application
intended. Please consult TQ Environmental LTD in selecting the most appropriate
sensors.
Pellistors show a general response to most combustible gases. Table 4 shows a typical
response for the TQ122-210 sensor to % LEL concentrations of various gases where the
sensor has been previously calibrated with 100% LEL methane.
Pellistors may be subject to poisoning in some applications. Common gases and vapours
which should be avoided include silicones and hydrogen sulphide. Even low levels
(100ppm) of eg hexamethyl disiloxane or hydrogen sulphide may cause irreversible
damage to the TQ122 series of pellistor based sensors even with short exposure.

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Table 4. TQ122-210 Response to Combustible Gases
GAS/VAPOUR
RESPONSE
(% LEL)
100% LEL Methane
100
100% LEL Propane
50
100% LEL n-Butane
40
100% LEL Acetone
30
100% LEL Hydrogen
80
1.7 PERFORMANCE TESTS
The performance of the TQ122-210 in conjunction with a TQ series 8000 control unit has
been tested against the relevant parts of BS EN 61779-1 and BS EN 61779-4. A copy of
the test results is available from TQ Environmental LTD.

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SECTION 2 - INSTALLATION
2.1 MECHANICAL INSTALLATION.
2.1.1 GENERAL.
The TQ122 Sensor is designed to be installed with a suitably certified junction box,
preferably with the sinter pointing downwards to prevent the direct ingress of water.
2.1.2 INSTALLATION GUIDELINES.
To ensure continued reliable operation of the TQ122 Sensor, the following installation
guidelines should be taken into consideration in the siting of sensors. More information on
flammable gas and oxygen sensor applications may be found in BS EN 50073: 1999. The
document may also prove useful for applications involving toxic gas sensors.
CAUTION
In safety critical applications the pellistor based sensors (TQ122-210,
TQ122-211, TQ122-212 & TQ122-215) must be used as part of a system
meeting the requirements of BS EN 61779-4:2000.
CAUTION
The calibration of the sensor may be affected by exposure to direct
sunlight. If it is necessary to install the sensor unit in a sunlit area,
provide an adequate sunshade for the sensor unit.
•For the monitoring of heavier-than-air gases, mount the sensor unit as close as practical
to the floor or ground. For monitoring of lighter than air gases, install the sensor unit as
high as practical.
•The sensor unit should be installed in a location where it is easily accessible for repairs.
•Mount the sensor unit in a position that minimises the risk of mechanical damage.
•Prevent water and dust accumulation from affecting operation by mounting the sensor
unit with the sinter at the bottom.
•It is important to ensure the connection between the TQ122 and the junction box is
watertight.
•The only method of mounting the TQ122 is through the M20 thread on the top of the unit.
2.2 ELECTRICAL INSTALLATION.
Figure 2 shows the installation of a 2-wire TQ122. Table 5 shows the connections of a
pellistor based sensor. An Addendum to this manual will be provided for installations using
sensing elements requiring connections which differ from those shown above.

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TQ122
DISPLAY /
CONTROL UNIT
24v DC POWER
SUPPLY
(1.5w Power Limited)
+
-
Load
Resistor
Yellow
Red
Figure 2 -- Wiring of Two Wire TQ122
Table 5. Connections to Pellistor Based Sensors
(TQ122-210, TQ122-211, TQ122-212, TQ122-215)
Cable
Colour
+2v Power Supply
Blue
0v
Red
Signal Out
Green
2.2.1 Cabling.

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For all installations involving 4-20 mA oxygen and toxic sensors TQ recommend that 2
core cables with overall screen be used. Individual cores should be 1.5mm2, type 7/0.53.
For the TQ122-210, 122-211, 122-212 & 122-215 sensors it is essential that the
resistance of each conductor does not exceed 3 ohm. Figure 3 shows an installation
where the sensor and control unit are separated by K metres. Table 6 shows the maximum
value of “K” for common types of cables. “K” is the maximum length in meters
recommended for use with the cable specified.
TQ122-210
TQ122-211
TQ122-212
TQ122-215 JUNCTION BOX
(E.G TQ8000)
RED
BLUE
GREEN
K (METRES)
Figure 3 –Separation of Sensor & Control Unit
Table 6. TQ122-210, TQ122-211, TQ122-212 TQ122-215 Recommended Cable
Lengths
X- Section Area
(mm2)
No. of
Wires/Size of
Wire (mm)
Approx. Resistance
@20C
(ohms/km/conductor)
“K”
(m)
0.5
1/0.80
34.3
80
1.0
7/0.43
18.3
150
1.5 *
7/0.53
12.0
250
2.5
7/0.67
7.4
380
* Recommended cable type for most applications

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CAUTION
It is important that for installation in hazardous areas, approved and
certified junction box and cable glands are used together with steel wire
armoured (SWA) cable when connecting to the power source and
Control/Display Unit.
CAUTION
Please contact TQ Environmental Ltd if there is any doubt concerning
the wiring of the TQ122 or its operation in a hazardous environment.

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SECTION 3 - COMMISSIONING & CALIBRATION
3.1 COMMISSIONING.
Prior to connecting power to the TQ122 Sensor, the following preliminary checks should be
made.
a. Ensure the Sensor is screwed tightly into its junction box.
b. Check that the Sensor is correctly wired.
c. It is essential that pellistors (TQ122-210, TQ122-211, TQ122-212 & TQ122-215)
operate from the correct head voltage. For the sensor types above, this head voltage is
2.0, 2.5, 2.0 & 2.0v respectively. The procedure for establishing this is detailed in the
Operating Manual for the TQ8000 Control Unit. If the TQ8000 unit is NOT used with
these sensors the End-User MUST use a Control Unit which can provide these head
voltages.
CAUTION
TO AVOID DAMAGE TO THE EQUIPMENT, ENSURE THE VOLTAGE
APPLIED TO THE TQ122 DOES NOT EXCEED THE STATED VOLTAGE.
d. Sensors based upon pellistors do not always “fail safe” in the event of an accidental
short on any of the 3 wires connecting the sensor to the control unit or upon exposure
to flammable gas or vapour at concentrations approaching or exceeding the LEL of
the gas or vapour.
CAUTION
IT IS ESSENTIAL THAT PELLISTORS (TQ122-210, TQ122-211, TQ122-
212 & TQ122-215) ARE USED WITH A CONTROL UNIT WHICH CAN
INTERRUPT THE POWER TO THE SENSOR AND GIVE A WARNING
UNDER THE CONDITIONS STATED ABOVE. A SUITABLE CONTROL
UNIT IS THE TQ8000.
e. After power has been applied, let the sensor unit function for 60 minutes prior to
further monitoring.

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3.2 CALIBRATION.
The TQ122 is factory calibrated for the gas and range as engraved on the body of the
sensor. User adjustment of the instrument or output signal is not possible.
Instead any calibration adjustments (zero andspan) of the displayed value should be carried
out on the associated Monitoring Equipment or Control Unit attached to the TQ122.
Table 7 shows the concentration of gases normally used to check the calibration of the
various sensors. In each case the background gas is air, not nitrogen. In all cases except
TQ Part No 122-001 the “zero” gas is air. Nitrogen should be used as a “zero” gas for the
oxygen sensor. A suitable gassing cap should be used to introduce test gas to the sensor
Table 7. Concentration of Calibration Check Gases
Part No
Gas Measured
Calibration Gas
Concentration
122-001
O2
Air (21%)
122-002
CO
500ppm CO
122-003
H2S
25ppm H2S
122-004
SO2
20ppm SO2
122-007
NO
100ppm NO
122-210
Methane
2.5%vol CH4(50% LEL)
122-212
Ammonia
1.5% vol NH3
122-215
Hydrogen
2%vol H2(50%LEL)
122-013
Gassing cap and flow
through adaptor
The calibration and checking of the ethylene oxide (TQ122-017) and petrol (TQ122-211)
sensors should be carried out after discussion with TQ Environmental Ltd.

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SECTION 4 - MAINTENANCE
4.1 ROUTINE MAINTENANCE.
Please note there are no User Serviceable parts on the TQ122.
Ongoing repair of the sensor is not possible. If the sensor appears damaged, malfunctioning,
or is not functioning correctly following a calibration check (see section 3.2 Calibration) then
the sensor should be replaced.
It is recommended that a system calibration check is performed on a frequent basis (3 to 6
monthly intervals) depending on the application and local ambient conditions, to ensure
correct operation. If the sensor is slow to respond or does not reach the calibration value,
then this would indicate End of Life and the sensor should be replaced.
4.2 WARRANTY
When the TQ122 Gas Sensor is operated in accordance with conditions described in this
Manual the Standard Warranty is the shelf life detailed in Table 2.

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SECTION 5 –CERTIFICATION
Installations in hazardous areas are covered by certificate number:- SIRA 03ATEX1304X
SPECIAL CONDITIONS FOR SAFE USE
The TQ122 gas sensor shall not be used as a safety related device as defined in ATEX
Directive 2014/34/EU.
The TQ122 gas sensor shall be connected to an enclosure that has been suitable
certified by a notified body and provides:-
•The external conductors with suitable mechanical and explosion protection,
•The setting compound with protection against light and mechanical damage,
•Suitable earthing or equi-potential bonding facilities.
The TQ122 may be used with flammable gases and vapours with apparatus groups IIA, IIB,
IIC and temperature classes T1, T2, T3, T4, & T5 (where the ambient temperature does not
exceed +30 degrees Celsius) or T6 (up to a maximum of +40 degrees Celsius).
Installation shall be carried out by suitably trained personnel in accordance with the
applicable code of practice e.g. EN 60079-14, and using approved cable glands.
Inspection and maintenance of this equipment shall be carried out by suitably trained
personnel in accordance with the applicable code of practice e.g. EN 60079-17.
Repair of this equipment shall be carried out by suitably trained personnel in accordance
with the applicable code of practice e.g. EN 60079-19.
The entry into service, use, assembling, and adjustment of the equipment shall be in
accordance with this Operating Manual.
The certification of this equipment relies upon the followingmaterials used in its construction:
Covers & Housings:Grade 316 stainless steel
Sintered Element: Grade 316 stainless steel
If the equipment is likely to come into contact with aggressive substances, then it is the
responsibility of the user to take suitable precautions that prevent it from being adversely
affected, thus ensuring that the type of protection provided by the equipment is not
compromised.
Aggressive substances, e.g. acidic liquids or gases that may attack metals, or
solvents that may attack polymeric materials.
Suitable precautions: e.g. regular checks as part of routine inspections or
establishing from the material's data sheets that it is resistant to specific chemicals.

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Certification Details:-
Surveillance Authority Marking
2813
TQ’s Manufacturing Mark
TQ122
ATEX Group & Category
ll 2G
CENELEC Marking
Ex db llC T5 Gb ( Ta= -20 to +40C)
Ex db llC T6 Gb ( Ta= -20 to +30C)
EN 60079-0:2018+CORR1:2020
EN 60079-1:2014+CORR1:2018
Apparatus Certificate No
SIRA 03 ATEX l304X
Certificate Holder
TQ Environmental Ltd
DECLARATION REGARDING DIRECTIVE 2014/34/EU
This declaration confirms that the TQ122 Gas Sensor has been designed and constructed
in accordance with good engineering practice and is suitable for use in foreseeable indoor
and outdoor industrial environments. TQ Environmental Ltd attests to the following:
▪The equipment has been designed such as to avoid the possibility of physical injury or
other harm that may be caused by direct or indirect contact –ESHR 1.2.7
▪Analysis reveals that dangerous situations due to possible operating faults, including
foreseeable misuse, are precluded –ESHRs 1.0.2 & 1.2.7
▪There is no potential source of ignition formed by optical or acoustic radiation or
electromagnetic energy –ESHR 1.3.1
▪The equipment does not emit, nor is susceptible to, electrostatic discharges, extraneous
voltages or environmental effects when used within the stated operating conditions –
ESHRs 1.3.2 & 1.4.1
▪Authorised European Representative
Terrence Murphy
Murco Services
5 Sandymount
Cobh, Co Cork
P24 PW52
Ireland.

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ADDENDUM I DUCT MOUNTING KIT Pt No 122-019
1 GENERAL DESCRIPTION
The TQ122 series may also be supplied with a kit which will allow the TQ122 gas detector
to be fitted in a constant velocity, low pressure air duct and provide a means of calibrating
or checking the calibration in situ.
DIRECTION OF
AIRFLOW
FILTER
VENT
JUNCTIONBOX
TQ122SENSOR
RUBBERCAP
GASSING
(CALIBRATION)
POINT
DUCT
SEALINGSTRIP
DUCTINTERIOR
DUCTEXTERIOR
DUCTSECURINGPOINTS
Figure 4 –Duct Mounting Kit Overview
2 INSTALLATION
The sensor on the TQ122 duct mounting kit should be positioned vertically from the top of
the duct as shown in Figure 4 to prevent any condensing water collecting in the sensor.
The orientation if the duct mounting kit MUST be as shown in Figure 5 below. The latter is
important as, during normal operation, a partial vacuum inside the sensor must be created
and maintained to ensure a constant flow of gas through the cell. Any other orientation
may cause air in the sensing element to stagnate
This manual suits for next models
4
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