Envent 331S, 330SDS, 330S, 331SDS User Manual

Envent Engineering Ltd.

Hydrogen Sulfide Analyzer

Model 330S & 331S

Model 330SDS & 331SDS

U

SER'S MANUAL

Revision 2.4
Jan 2019

Table of Contents

INTRODUCTION ................................................................................................................................................................... 1

Contacting Envent Engineering Ltd ......................................................................................................................................... 1

•

Canada Office: (Main) ........................................................................................................................................... 1

•

USA Office: ............................................................................................................................................................ 1

•

China Office: ......................................................................................................................................................... 2

Warranty & Liability Statements ............................................................................................................................................. 2

Limitation of Warranty ............................................................................................................................................................ 2

Disclaimer ................................................................................................................................................................................ 3

Key Symbols ............................................................................................................................................................................. 3

Warnings & Cautions ............................................................................................................................................................... 3

•

Warning & Cautions for 330S & 331S H2S Analyzers ............................................................................................ 4

•

Warning & Cautions for 330S Analyzer Only ........................................................................................................ 5

•

Warning & Cautions for 331S H2S Analyzer Only .................................................................................................. 5

Analyzer Specifications ............................................................................................................................................................ 6

PRINCIPLE OF OPERATION ................................................................................................................................................... 8

Physical Reaction ..................................................................................................................................................................... 8

Analysis Cycles ......................................................................................................................................................................... 9

•

Dual Sensor Analysis cycle (SDS): ........................................................................................................................ 11

INSTALLATION ................................................................................................................................................................... 12

Installation Requirements ..................................................................................................................................................... 12

•

Electrical Requirements ...................................................................................................................................... 12

•

Location for the System ...................................................................................................................................... 12

•

Space Requirements ........................................................................................................................................... 13

•

Sample Point Selection ....................................................................................................................................... 14

•

Sample inlet & sample sweep ............................................................................................................................. 14

•

Vent line .............................................................................................................................................................. 14

•

Sample Volume & Flow Rate .............................................................................................................................. 15

Installation of Analyzer Components .................................................................................................................................... 16

Analog Outputs ...................................................................................................................................................................... 16

Sample Chamber ................................................................................................................................................................... 18

•

Sensor Block ........................................................................................................................................................ 18

•

Window & Gasket ............................................................................................................................................... 18

•

Aperture Strip ..................................................................................................................................................... 19

•

Humidifier Unit ................................................................................................................................................... 19

•

Eductor Block ...................................................................................................................................................... 21

Receiving the Analyzer .......................................................................................................................................................... 22

•

Unpacking the Analyzer ...................................................................................................................................... 23

•

Standard spare parts for 330S H2S analyzers: ..................................................................................................... 23

•

Standard spare parts for 331S H2S analyzers: ..................................................................................................... 24

Installation procedure & Start-up ......................................................................................................................................... 24

OPERATION & CONFIGURATION ........................................................................................................................................ 26

Analyzer Display Interface ..................................................................................................................................................... 26

CALIBRATION PROCEDURES ............................................................................................................................................... 28

H2S Gas Calibration ................................................................................................................................................................ 28

Re-zero Sensor Procedure ..................................................................................................................................................... 29

MAINTENANCE .................................................................................................................................................................. 31

H2S Sensing Tape Change Procedure ..................................................................................................................................... 31

Sample Conditioning System Cleaning Procedure ................................................................................................................ 32

•

Material List ........................................................................................................................................................ 32

•

Procedure ........................................................................................................................................................... 32

TROUBLESHOOTING .......................................................................................................................................................... 34

APPENDICES ...................................................................................................................................................................... 44

Recommended Spare Parts List ............................................................................................................................................. 44

Chico A Sealing Compound: For sealing fittings in Hazardous Locations .............................................................................. 45

Safety Data Sheet for H2S Sensing Tape ................................................................................................................................ 46

Risk Assessment - Safety Information ................................................................................................................................... 51

List of Figures

Figure 1. H2S Analyzer Principle of Operation Diagram .............................................................................................9

Figure 2. H2S Analysis Cycle ..................................................................................................................................... 10

Figure 3. Space Requirements for the 330S & 331S H2S Analyzers ......................................................................... 13

Figure 4. 331S Recommended Venting for 331S (Same for 330S model) ............................................................... 15

Figure 5. AO 4-20 mA Output Wiring Options ......................................................................................................... 17

Figure 6. Sample Chamber (Exploded View) ........................................................................................................... 18

Figure 7. Envent's Humidifier Unit for 330S & 331S ................................................................................................ 20

Figure 8. Humidifier Unit Installed in a 331S H2S Analyzer ..................................................................................... 21

Figure 9. Eductor Block (Venturi Effect) .................................................................................................................. 22

Figure 10. 330S Display (left) & 331S Display (right) ............................................................................................... 26

Figure 11. 331S & 331SDS Sensing Tape Change .................................................................................................... 31

List of Tables

Table 1. 330S/331S H2S Analyzer Specifications ........................................................................................................7

Table 2. Sample Volume and & Flow Rate .............................................................................................................. 15

Table 3. Aperture Strips & Ranges ........................................................................................................................... 19

Table 4. Display Button Description/Function ........................................................................................................ 26

Table 5. Display LED Description/Function .............................................................................................................. 27

Table 6. Hydrogen Sulfide Properties ...................................................................................................................... 51

Table 7. Hydrogen Sulfide Quantities & Health Effects ........................................................................................... 51

INTRODUCTION

This manual provides all the necessary information to install, operate and maintain the
330S, 330SDS, 331S and 331SDS model H2S Analyzer units. This manual is
intended for all technical level users.

Throughout this document will be referring to the models 330S and 331S. However,
the information applies equally to the 330SDS and 3301SDS (Dual sensor), unless
otherwise stated. To clarify, the difference between an "S" model and a "SDS" model
analyzer is the second sensor the "SDS" has to measure H2S giving it the capability to
measure H2S from two different samples at the same time; the DS stands for Dual
Sensor.

The Envent 330S/331S H2S Analyzer is a uniquely rugged and simple design that
utilizes lead acetate based detection which provides a linear and interference-free
output of H2S concentration. This analyzer can measure a wide range of hydrogen
sulfide concentrations from parts per billion (ppb) concentrations to parts per million
(ppm) concentrations. With the addition of a dilution sample system, it can read high
concentrations in percentage up to 100%. There are other options available such as
the sample system for H2S analysis in liquids or the addition of a hydrogen reaction
furnace for total sulfur measurements.

Contacting Envent Engineering Ltd

This manual covers most of the important information the user is going to need to
install, operate and maintain the 330S/331S H2S Analyzers. If more information is
required, you can contact us at:

Canada Office: (Main)

Toll Free: 1 (877) 936 - 8368
Tel: (403) 253 - 4012
Fax: (403) 253 - 4016
Email: [e-mail]

Hours of operation: Monday to Friday – From 8:00 am to 4:30 pm (Mountain Time
Zone). Offices closed on statutory holidays.

USA Office:

Tel: [phone] - 4421

Envent Engineering Ltd. Page 1 Revision 2.4

China Office:

Tel: (86) 138 - 0119 - 1148

For further information on our products and most updated manuals/product catalog
please visit: www.envent-eng.com

Warranty & Liability Statements

Products manufactured and supplied by Envent Engineering Ltd unless otherwise
stated are warranted against defects in materials and workmanship for up to 18
months from the date of shipment or 12 months from date of start-up, whichever
occurs first. During the warranty period the manufacturer will, as its option, either
repair or replace products, which prove to be defective.

The manufacturer or its representative can provide warranty service at the buyer's
facility only upon prior agreement. In all cases the buyer has the option of returning
the product for warranty service to a facility designated by the manufacturer or its
representatives. The buyer shall prepay shipping charges for products returned to a
service facility, and the manufacturer or its representatives shall pay for return of the
products to the buyer. The buyer may also be required to pay round-trip travel
expenses and labour charges at prevailing labour rates if warranty is disqualified for
reasons listed below.

Limitation of Warranty

The foregoing warranty shall not apply to defects arising from:

• Improper or inadequate maintenance by the user;

• Improper or inadequate unpacking or site preparation/installation;

• Unauthorized modification or misuse;

• Operation of the product in unfavorable environments, especially high

temperature and/or high humidity;

• Corrosive or other damaging atmospheres or otherwise outside published
specifications of analyzer.

Envent Engineering Ltd carries no responsibility for damage cause by transportation
or unpacking, unless otherwise specified in the incoterms.

Extended warranty may be available with certified start-up. Contact Envent
Engineering Ltd for details.

Envent Engineering Ltd reserves the right to change the product design and
specifications at any time without prior notice.

Envent Engineering Ltd. Page 2 Revision 2.4

Disclaimer

No other warranty is expressed or implied. The manufacturer specially disclaims the
implied warranties of merchantability and fitness for a particular purpose.

The sole remedy of the buyer shall in no case exceed the purchase price of the
analyzer.

The manufacturer shall not be liable for personal injury or property damage suffered in
servicing the product. The product should not be modified or repaired in a manner at
variance with procedures established by the manufacturer.

Key Symbols

The following symbols are used throughout this manual. They are intended to draw
attention to important information.

Description of hazards that could result in major injury or death.

Description of hazards that could result in minor injury or property damage.

Description of important information regarding safety of personal and/or property.

Caution: hot surface.

Description of useful information to help understand a concept.

Warnings & Cautions

This section covers all warnings and cautions for the 330S and 331S H2S analyzers.
They are divided into warnings and cautions applicable to both the 330S and 331S,
only 330S, and only 331S H2S analyzers. Please read and understand all statements
as they are for your own safety when installing, operating and maintaining the
analyzer(s). Some of these statements are also noted throughout the manual when
relevant.

Envent Engineering Ltd. Page 3 Revision 2.4

Warning & Cautions for 330S & 331S H2S Analyzers

Do not disconnect equipment unless power has been switched off or area is known to
be non-hazardous.

Turn off power before servicing. Ensure breakers are off before connecting or
disconnecting power supply.

Electrostatic Hazard – Backpan and Certification nameplate must be cleaned only
with a damp cloth to prevent static charging hazard.

Hydrogen Sulfide and/or other hazardous gases may be present under normal
operation – proper precaution and protective equipment is advised.

The analyzers input voltage range shown in Certification Nameplate (e.g., 120 –
240VAC) is limited when installing external devices (e.g., Solenoids).

Incorrect configuration of the analyzer may cause incorrect operation. Injury and/or
damage to facilities may occur. Check analyzer's functionality after configuration
changes have been made.

Total Sulfur Furnace reaches a temperature of up to 900 °C internally after 1 hour on.
Do not touch external surface as it can reach up to 150 °C. Allow enclosure 1 hour
after powering down the analyzer to cool down before servicing.

The analyzer should be mounted in an area in which it is not exposed to vibration,
excessive pressure, temperature and/or environmental variations.

Disassembly of the pressure regulator and solenoids in the field is not advised.
Consult Envent Engineering Ltd if the regulator or solenoid appears contaminated.

Before resuming line pressure, be sure that all port connections, sample sweep and
sample conditioning system are securely installed.

All connections must be leaktight to ensure the effectiveness of the analyzer as well
as safety. The user is solely responsible for the product selection, safety and warning
requirements for the application. If the equipment is used in a manner not specified by
Envent Engineering Ltd, the protection provided by the equipment may be impaired.

Do not use solvents, brake cleaners, soaps, detergents or rubbing alcohol to clean up
analyzer or sample system.

This unit requires a disconnect device rated 24 VDC and 5A max. It must be protected
by a circuit breaker rated 24 VDC and 5A max, and it is to be installed in accordance
with local electrical codes.

Envent Engineering Ltd. Page 4 Revision 2.4

This unit requires a disconnect device rated 240 VDC and 5A max. It must be
protected by a circuit breaker rated 240 VDC and 5A max, and it is to be installed in
accordance with local electrical codes.

Envent Engineering H2S Sensing Tapes are suitalbe for use, if stored in the original
sealed package, for 10 years fron date of manufacture. Tapes should be stored in a
coll dry location. If the seal on the package has been broken in storage, the H2S
Sensing Tape should be discarded.

Warning & Cautions for 330S Analyzer Only

Substitution of components may impair intrinsic safety and suitability for Class I,
Division 1.

Open circuit before removing cover.

Ensure that the analyzer received is suitable for the electrical classification of the
installation site:

• The 330S is designed for Class I, division 1 Groups CD
or Groups BCD (Check Analyzer Nameplate)

The glass window on the XP enclosure must remain installed in order to maintain area
classification.

Seals not poured. Pour seals before energizing the circuit).

Analyzer may utilize an optional CCS, Model 646 Series pressure switch located on
the side of the XP enclosure:

• Dual seal, MWP 500psi

• Annunciation is visible leakage from the pressure adjustment cover (flow from

this cover can indicate the possibility that a failed primary seal condition could
exist in the pressure switch).

Warning & Cautions for 331S H2S Analyzer Only

Substitution of components may impair suitability for Class I, Division 2.

The eductor is required with this model in order to maintain electrical safety and
certification in division 2 areas.

Envent Engineering Ltd. Page 5 Revision 2.4

Analyzer Specifications

Analyzer Specification

Optional

Features

Measurement
Method
Ambient
Temperature
Power 12-24 VDC @ less than 3W

Electrical
Certification

Output Ranges Standard ranges are between 10-100 ppb and 0-100 ppm
Response Time 20 seconds to 90% of step change
Accuracy ±1.5% of full range on channel 1 (for SDS Models, channel 2 has an

Display Graphic Liquid Crystal Display; menu is scrolled by internal button or

Outputs Two 4-20mA outputs (loop power required), optional 4-20mA powered

ASTM D4084 - 07: Standard Test Method for Analysis of Hydrogen
Sulfide in Gaseous Fuels (Lead Acetate Reaction Rate Method)
0-50 °C (standard) consult factory for other requirements, 0 to 90%
humidity (non-condensing)

Or, 100-240 VAC 50/60 Hz, 5W,
(300W when total sulfur option is included)
Fuse Rating: 5 Amps, 250V, Slow blow, Size: 0.201'' Dia x 0.787'',
Package/Case: 5 mm x 20 mm
Battery (for 1d Controller Board only): Lithium 3.6V, Dia 0.571'' & 0.992''
Long
330S­DS
331S­DS
For more information on Hazardous location certification, refer to the
Envent’s Website.

accuracy of ± 2.0%).
For dilution (option): ±2.5%
For Total Sulfur (Option): ±2.0%
For PPB (Option): Based on "base noise average"

magnetic wand (330S)

output boards are available
Serial Communication:
(1) RS-232 Modbus protocol
(3) RS-485 Modbus protocol (One RS-485 for remote display option)
Ethernet port as an optional feature
4 SPDT relays (120 VAC 5A maximum)
4 solid state solenoid drivers

Class I, Division 1 Groups B C D or CD T3C Tamb 0 °C to +
50 °C
Class I, Division 2 Groups B C D or CD T3C Tamb 0 °C to +
50 °C

Total Sulfur Utilized when all sulfur compounds need to be measured. A Total sulfur

Dilution Sample
System
Liquid Sampling Utilized when a liquid sample conditioning system is required to

Envent Engineering Ltd. Page 6 Revision 2.4

reaction furnace is added which allows the analyzer to measure total
sulfur
Utilized when the analyzer needs to measure ranges above 100 ppm. A
permeable membrane dilution system

measure hydrogen sulfide in Liquids

Parts Per Billion Utilized when analyzer requires to read in parts per billion (<1 ppm)
Low Tape Sensor Utilized when an alarms is required when the H2S sensing tape needs

to be changed

Low Pressure

Utilized for alarming when sample pressure drops below 10 PSI
Switch
AO Powered

Utilized for loop-powered analog outputs
Boards
Expander AO

Utilized when more than two analog outputs are required
Board
Ethernet Port Utilized for TCP/IP communication capabilities
Auto Calibration Utilized to initiate a calibration based on time of day or manually

Table 1. 330S/331S H2S Analyzer Specifications

Envent Engineering Ltd. Page 7 Revision 2.4

PRINCIPLE OF OPERATION

Physical Reaction

Envent's models 330S and 331S H2S analyzers use ASTM D4084 – 07: Standard
Test Method for analysis of hydrogen sulfide in gaseous fuels (Lead Acetate reaction
rate method). This method uses lead acetate impregnated paper. Throughout this
document the term lead acetate tape will be written as "H2S sensing tape".

The H2S sensing tape reacts when in contact with hydrogen sulfide by the compound
relationship shown below. This tape does not react to any other sulfur compounds in
the gas stream. This makes it free from interference when more than one sulfur
compound is present in the sample stream. The H2S reaction is visibly evident by a
brown stain directly on the H2S sensing tape.

The electronics built into the models 330S and 331S have been programmed to
measure the rate of darkening over time which, in turn, gives the hydrogen sulfide
concentration level. When no H2S is in contact with the H2S sensing tape, the
analyzer sensor reads 1000 mV (+/- 100 mV).

The sensor block has a LED and a photodiode detector. The LED emits a red beam of
light which is reflected off of the H2S sensing tape to the photodiode which detects the
light intensity. The darker the H2S sensing tape becomes when in contact to H2S, the
less light the photodiode detector receives reducing the millivolt value, which in turn,
increases the H2S value. The "SDS" models uniquely measures rate of change on
both sides of the H2S sensing tape, allowing for simultaneous readings of two
separate samples.

OH

2

2)(

+ →+

COOHCHPbSCOOCHPbSH

3232

Envent Engineering Ltd. Page 8 Revision 2.4

Figure 1 above shows a flow and pressure regulated of a filtered sample gas passing
through the humidifier into the sample chamber. An aperture in the sample chamber,
which differs in sizes depending on the application, allows the gas to come in contact
with the H2S sensing tape creating a brown stain.

Flow and pressure are the most important variables when measuring H2S and must
be kept at a constant state for the analyzer to measure H2S properly. Pressure should
be kept at a constant 15 psig. The lowest pressure found to be tolerable for proper
H2S measurement is 0.5 psig. Flow must be kept at a constant flow of 2 cm (83.63
cc/min). A change in flow of +/- 1 cm affects the reading by 10% of full range.

Analysis Cycles

The analysis of the color rate of change on the H2S sensing tape is measured in
analysis cycles. An analysis Cycle lasts up to a maximum of 720 seconds (12
minutes).

Do not change the Maximum Analysis Time, consult Envent Engineering Ltd.

Analyzers sold prior to Mid-August 2016 are set to have a 360 second analysis cycle.

Figure 1. H2S Analyzer Principle of Operation Diagram

Envent Engineering Ltd. Page 9 Revision 2.4

Once an analysis cycle is complete, the motor moves the H2S sensing tape giving the
sensor block new tape surface area to start the analysis again. In normal operation, if
the analyzer is being exposed to H2S within its range, the analysis cycle should last
between 150 to 210 seconds (1.5 to 2.5 min); the cycle lasts 720 seconds if no H2S is
present.

Figure 2. H2S Analysis Cycle

Figure 2 shows a complete analysis cycle from when the motor has advanced the H2S
sensing tape from a previous analysis (1), to the end of the current analysis (4). Once
the H2S sensing tape has finished moving and new tape surface area is exposed, the
reflection of light from the LED to the photodiode detector is at its maximum and
results in a voltage output from the sensor block of 1000 mV (+/- 100 mV). This
voltage is captured by the analyzer and it is referred to as the "Zero Voltage". The
zero voltage will vary for each surface area of the H2S sensing tape and will represent
the starting point for the H2S reading for that cycle.

From stage (2) to (4) the H2S value starts increasing as the millivolt value drops from
exposure to H2S. This stage is called "RRA Analysis". The RRA stands for Rapid
Response Algorithm and it is the instantaneous H2S readings calculated every 67 ms.
As the H2S sensing tape darkens, the RRA value starts going up every second.
Although the RRA values are calculated almost instantaneously, they are not as
accurate as the final reading obtained at the "Concentration Calculation" stage (3) to
(4). However, RRA values can be used as a trigger alarms setpoint in case the
application requires a rapid response time (less than the RRA Analysis completion).

Envent Engineering Ltd. Page 10 Revision 2.4

The first part of the RRA Analysis (2) to (3) completes when the mV value drops 100
mV. Once it drops 100 mV, stage (3) to (4) "Concentration Calculation" starts.

On this stage, the H2S slope is optimal for calculating the final H2S value for that
Cycle. Algorithms are used by the controller board to calculate as accurately as
possible the H2S final value. Once the final value is obtained, it will stay at that value
(shown in the display and 4-20 mA analog outputs) until the next cycle has finished
and updates the H2S current reading. This stage will always be 1/5 of the amount of
time it takes stage (2) to (3) to complete. Thus, if stage (2) to (3) took 600 seconds,
then stage (3) to (4) will take 120 seconds.

It is important that the analyzer is used for its calibrated H2S range. Do not use this
unit for an application that will require readings outside of its calibrated range. This will
cause the H2S sensing tape to run out faster and may cause less accurate readings.
The range is determined by the aperture strip in the sample chamber. For more
information analyzer ranges, refer to "Aperture Strip" on page 19.

Dual Sensor Analysis cycle (SDS):

Dual sensor analyzers have two sensors that read H2S from two different samples at
the same time, e.g. Sensor 1: 0-20 ppm H2S Sensor 2: 0-200 ppm H2S. The analysis
cycle process is the same per sensor as explained earlier in this section; however,
some extra algorithms have been implementing to help with the interaction between
the two sensors and their analysis cycles' timing.

Both analysis cycles for each sensor will always start at the same time. When the
motor moves and new H2S sensing tape area is exposed, a new analysis cycle has
started for both sensors. However, the analysis cycles from each sensor will finish at
different times. Either sensor 1 or sensor 2 will finish its analysis cycle first.
Regardless of which sensor finishes first, it will wait for the other sensor to complete
its analysis cycle. Once both sensors have completed their analysis cycles, the motor
will move and new H2S sensing tape area is exposed for a new analysis cycle.

It is important to clarify that when the first sensor has finished its analysis cycle, even
when it is waiting for the second sensor to complete its analysis cycle, it immediately
updates any outputs associated with that sensor (Analog output 4-20 mA, alarms,
display H2S value, etc.).

Envent Engineering Ltd. Page 11 Revision 2.4

INSTALLATION

Installation Requirements

Electrical Requirements

The 330S/331S H2S analyzer's controller board can either be 110-240VAC or 10­32VDC. Consult the analyzer nameplate attached to it or factory calibration certificate
for more information.

Controller board ground connection to chassis is represented by the letters “FG” and
ground symbol.

Certification nameplate shows the voltage range at which the controller board can
withstand (e.g., 120 – 240 VAC), however, when using external devices which are
powered by the controller board (e.g., solenoids), that voltage range no longer applies
and only the external device’s voltage rating shall be used; e.g., 120 VAC rated
solenoid, the analyzer shall be powered with only 120 VAC and not 240 VAC.

The power consumption for a VDC analyzer is 3 Watts and for a VAC is 5 Watts. For
the total sulfur option the power consumption 300 Watts.

Location for the System

First to be considered is the electrical area classification the analyzer will be installed
in. Make sure the analyzer meets the requirements for the installation site. The 330S
H2S analyzer is suitable for Class I, Division 1 Groups CD (or Groups BCD by
customer request). The 331S H2S analyzer is suitable for Class I, Division 2 Groups
ABCD.

When the total sulfur option is used, the 330S is rated for Class I, Division 1 Groups
BCD and the 331S is for Class I, Division 2 Groups BCD.

The 330S/331S H2S analyzer should be mounted in an area in which it is not exposed
to vibration, excessive pressure, temperature and/or environmental variations. The
ambient temperature range for the 330S/331S H2S analyzers is 0 to 50 Degree
Celsius. If the analyzer is installed in an area where temperatures go out of this range
or it varies abruptly, Envent Engineering Ltd has options such as cabinets or shelters;
consult Envent Engineering Ltd.

Envent Engineering Ltd. Page 12 Revision 2.4

Space Requirements

Figure 3. Space Requirements for the 330S & 331S H2S Analyzers

Envent Engineering Ltd. Page 13 Revision 2.4

Make sure to leave at least 1 feet of extra space on the left side of the 330S H2S
analyzer. This will allow proper opening of the side door located at the upper blue
chassis where the H2S sensing tape is located.

Sample Point Selection

The sample to the 330S/331S H2S analyzer must be representative of the process
stream and should be taken from a point as close as possible to the analyzer to avoid
lag times and sample degradation in the tubing. A probe must be installed vertically
on a horizontal section of pipe ensuring that the sample is drawn from the middle third
of the pipeline.

An optional Genie GPR Probe regulator may be used. The function of this probe is to
ensure a clean dry sample to the analyzer and to reduce the pressure of the sample.
The lower pressure will improve the response time of the analyzer. Refer to Figure 4.

It is advisable that the probe not be installed on a vertical pipe.

Sample inlet & sample sweep

1/4 inch 316 stainless steel tubing and fittings are recommended for the sample inlet
and sample sweep tubing. Sample sweep can be connected to a flare line if available.
Refer to Figure 4.

1/8 inch 316 stainless steel tubing can also be used if the response time of the
analyzer is of particular concern.

Vent line

3/8 inch stainless steel tubing and fittings are recommended for the vent line to a
maximum of 6 feet in length. 1/2 inch stainless steel tubing should be used for vent
lines exceeding 6 feet. The tubing should be installed with a slight downward slope
and should be as short as possible. Refer to Figure 4.

The sample vent line must be tubed to atmospheric pressure outside and cannot be
connected to a flare line or header.

Envent Engineering Ltd. Page 14 Revision 2.4

Figure 4. 331S Recommended Venting for 331S (Same for 330S model)

Sample Volume & Flow Rate

The sample should be supplied to the 330S/331S H2S analyzer at 10-15 psig and at a
flow of 83.63 cc/min (set flowmeter at 2.0). A bypass sweep is recommended to
reduce sample lag time in the sample line if it is at high pressure or it is longer than 15
feet (The Standard H2S conditioning sample system has a bypass sweep). The
standard sample tubing material is 1/4" 316 stainless steel; however, 1/8" stainless
steel tubing can be used if the response time is critical (refer to Table 2).

Tube
Size
(")

3/8 20 0.319 0.810 5 2359 800 36.30 2178

3/8 20 0.319 0.810 5 2359 200 9.07 544

3/8 20 0.319 0.810 5 2359 50 2.27 136

1/4 20 0.181 0.459 5 2359 800 11.69 701

1/4 20 0.181 0.459 5 2359 200 2.92 175

1/4 20 0.181 0.459 5 2359 50 0.73 44

1/8 20 0.081 0.205 5 2359 800 2.34 140

1/8 20 0.081 0.205 5 2359 200 0.59 35

1/8 20 0.081 0.205 5 2359 50 0.15 9

Tube
Gauge

ID (") ID (cm) Flow

(SCFH)

Table 2. Sample Volume and & Flow Rate

Flow
Std.
(cc/min)

Pressure
(PSIA)

Lag
Time per
100' (min)

Lag
Time per
100' (sec)

Envent Engineering Ltd. Page 15 Revision 2.4

Carbon steel sample line and/or fittings are not acceptable.

Installation of Analyzer Components

In this section, some components of the 330S/331S H2S analyzer will be covered in
more details as well as the optional components added to the system at customer
request. A brief explanation of type, functionality, set up and options will be described.

Total Sulfur and Dilution system options will not be covered in this section. Please
refer to Total Sulfur and Dilution manuals.

Analog Outputs

The H2S controller board has two isolated loop power 4-20mA outputs which can be
set up for different variable outputs. Loop power (10-32 Volts) sourced from the end
device (PLC) is required for the analog to output. Figure 5 shows the different wiring
set ups for the analog outputs.

The third wiring option shown in Figure 5 uses Envent's powered AO board(s) to
provide self-powered analog outputs. These boards are available at Envent
Engineering Ltd.

The factory default variable for the two analog outputs is the current H2S reading on
sample 1, labeled in the ICE software as "Sample 1 H2S – Current Value", meaning
both analog outputs are based on the H2S readings for sample 1. For SDS models,
analog output 2 outputs the variable for sample 2.

Envent Engineering Ltd. Page 16 Revision 2.4

Figure 5. AO 4-20 mA Output Wiring Options

Envent Engineering Ltd. Page 17 Revision 2.4

Sample Chamber

The sample chamber is the component that allows the H2S sample to come in contact
to the H2S sensing tape which in turn is read by the sensor block. The sample
chamber is made of the following components:

Figure 6. Sample Chamber (Exploded View)

Sensor Block

The sensor block measures the intensity of the LED light reflected off of the H2S
sensing tape. It is composed of an electronic board, a red light emitting diode and a
photodiode, refer to Figure 6. As the tape gets darker due to exposure to H2S, the
photodiode receives less light. Less light translates to more H2S.

Window & Gasket

These two components seal the small compartment where the H2S comes inside the
sample chamber, refer to Figure 6. The window keeps a clear view for the LED and
the photodiode to work properly and isolates them from the sample gas. The rubber
gasket seals the Sample Chamber compartment preventing any leaks.

Envent Engineering Ltd. Page 18 Revision 2.4

Aperture Strip

The sample chamber has a fixed size aperture of ¼ inch which is used for
concentrations in between 1 ppm to 16 ppm.

For concentration applications below 1 ppm or above 16 ppm an aperture strip is
installed behind the window in the Sample Chamber, refer to Figure 6. These aperture
strips keep the analysis time to be approximately the same regardless of the range.

Various sizes of apertures match different measurement ranges. Table 3 shows the
aperture size according to its range.

H2S Range Aperture Strip Envent PN

50 ppb to 1 ppm ppb style 330110

1 ppm to 16 ppm None (1/4" fixed aperture size) N/A
16 ppm to 30 ppm 1/16" 330103
30 ppm to 50 ppm 1/32" 330102

50 ppm to 100 ppm Pin Holes 330100

100 ppm to 500 ppm Laser Dot 330109

Over 500 ppm Addition of a dilution panel. Consult Factory.

Table 3. Aperture Strips & Ranges

Aperture strips can be changed to accommodate for a different range application.
Refer to the table shown above to select the best option on the new concentration
application. Contact Envent Engineering Ltd to purchase an aperture strip.

Remember: gain and span values on analog outputs will have to change based on
new range application. Please re-calibrate analyzer. Refer to "H2S Gas Calibration" on
page 28.

The adhesive used to glue the aperture strip in its place is RTV108 Translucent
Adhesive. RTV102, RTV103, and RTV109 could also be used.

Humidifier Unit

For the H2S to adhere to the surface of the H2S Sensing tape, it needs to be
humidified. The humidifier unit helps having constant moisture content in the sample
which increases the chemical reaction on the H2S Sensing tape. Envent Engineering
Ltd offers a unique design of humidifiers meant to meet the requirements for

Envent Engineering Ltd. Page 19 Revision 2.4

humidification of the sample before it gets into contact with the H2S sensing tape;
refer to Figure 7 .

Figure 7. Envent's Humidifier Unit for 330S & 331S

The humidifier works by using Nafion Tubing. This material has the capability to
transports water vapor from the most humidified medium to the driest medium. The
sample gas traveling inside the Nafion tube is dryer than the outside of the tube which
is being saturated with water, thus, humidifying the gas sample. It is important to have
a constant flow to create a constant humidification of the sample gas.

The humidifier unit can be filled with distilled water or 5% Acetic Acid up to where the
line indicates on the unit. Acetic acid is preferable over distilled water since it prevents
the liquid to create mold and fungus overtime. Also the freezing point for water is 0 °C
and for 5% Acetic Acid is -2 °C making it more reliable under freezing temperatures.

For the SDS models, the humidifier has two inlet and outlet ports. It is important to
make sure that the tubing is not connected to the wrong port. The Vinyl tubing that
connect to the humidifier are label with a 1 and a 2, make sure they are matched
when installing them to the humidifier.

The analyzer should not be exposed to ambient temperatures lower than 0 °C.
By default, all 330S/331S H2S analyzers have a temperature alarm set to 0 °C
descending.

Envent Engineering Ltd. Page 20 Revision 2.4

The analyzer should be mounted in an area in which it is not exposed to vibration,
excessive pressure, temperature and/or environmental variations.

Figure 8 shows know how to install the humidifier unit in a model 331S H2S analyzer.
Same principle applies for the model 330S H2S analyzer.

Figure 8. Humidifier Unit Installed in a 331S H2S Analyzer

Eductor Block

The analyzer reading can be affected by positive or negative pressure on the sample
vent line. This can be caused by strong winds blowing across or directly into the vent;
or by mechanical venting (exhaust fan). The eductor will eliminate any influence on
the analyzer reading; refer to Figure 9.

Envent Engineering Ltd. Page 21 Revision 2.4

The eductor is required with this model in order to maintain electrical safety and
certification in division 2 areas.

In cold climates, since the analyzer is venting a moist sample, freezing can occur. The
educator will help reduce freezing problems in the vent line due to the increased
velocity and drying effect of the sweep gas. The eductor vent can be retrofitted to
existing analyzers.

In normal conditions, the eductor makes a noise similar to a gas leak. This noise is
normal and it is due to the 15 psig pressure being expelled through the restricted
fitting creating suction from the gas vent line (Venturi Effect). DO NOT block the
opening at the bottom of the eductor or the modified elbow fitting.

Receiving the Analyzer

Figure 9. Eductor Block (Venturi Effect)

Inspect the packaging for external damage right after is received. If there is any
physical damage, please contact Envent Engineering Ltd and request that the
carrier's agent be present when the analyzer is unpacked. If a disagreement arises
the incoterms agreed by the seller and the customer will overrule any dispute.

Envent Engineering Ltd. Page 22 Revision 2.4

Unpacking the Analyzer

If damage is found in the shipping container see previous section

1. Open the shipping container and remove the foam packing or other packing
materials from the shipping box

2. Take out the analyzer and the start-up kit

The 330S H2S analyzer with a standard Sample conditioning system weights
approximately 105 lb. Unpacking and transporting requires a minimum of two
persons.

3. Make sure the start-up kit is complete (refer to list below). For some special and
more complex analyzers, there might be extra parts in the start-up kit.

Standard spare parts for 330S H2S analyzers:

1. 330S Customer Binder

• Customer Manual(s) and Addendums

• Factory Calibration Certificate

• Factory Configuration

• Drawing Package

• Cal Gas Certificate(s)

2. USB flash drive (containing all documentation)

3. 300' H2S Sensing Tape. Part No. 330133XS

4. 1 Liter Analyzer Fluid. Part No. 330129

5. Funnel

6. 330S Serial Comm. External Cable (USB to Mini USB). Part No. 600002

7. Humidifier (uninstalled). Part No. 330061 (Part No. 330061D for SDS)

8. Bolts For explosion proof enclosure (x22)

Envent Engineering Ltd. Page 23 Revision 2.4

Standard spare parts for 331S H2S analyzers:

1. 331S Customer Binder

• Customer Manual(s)

• Factory Calibration Certificate

• Factory Configuration

• Drawing Package

• Cal Gas Certificate(s)

2. USB flash drive (containing all documentation)

3. 300' H2S Sensing Tape. Part No. 330133XS

4. 1 Liter Analyzer Fluid. Part No. 330129

5. Funnel

6. 331S Serial Comm. External Cable (USB to Mini USB). Part No. 600002

7. Humidifier (uninstalled). Part No. 330061 (Part No. 330061D for SDS)

Installation procedure & Start-up

The following steps should be followed for proper installation and start-up of the
analyzer.

1. Unpack the analyzer and check for damages.

2. Ensure the analyzer power supply and range are suitable for the installation
location.

3. Check that the hazardous location rating is suitable for the installation location.

4. Ensure that the selected installation site provides adequate room for maintenance
and repair.

5. Select an installation location close to the sample point.

6. Bolt the analyzer to the wall with the H2S sensing tape drive at approximately eye
level.

7. Wire the power, analog outputs and discrete outputs from the analyzer.

8. Tube the Sample inlet, sample sweep, and sample vent lines from the analyzer.

9. Ensure there is enough H2S Sensing tape.

10. Install the Humidifier, if applicable. Ensure there is enough 5% acetic acid or
distilled water in the humidifier.

Envent Engineering Ltd. Page 24 Revision 2.4

11. Apply power to the analyzer. The display will illuminate and the H2S sensing tape
will advance for a few seconds.

12. Press the menu button until mV is displayed. Check that the mV reading is 1000
mV (± 100 mV).

There are two mV values shown in the display, the "mV Zero" and the "mV" Values.
Check for the "mV" Values.

For the SDS models, check for "Sensor 1 mV" and "Sensor 2 mV".

13. Make sure the sample inlet valve, sample sweep valve, and pressure regulator are
completely closed. The pressure regulator is completely closed when the knob
handle is counter clock wise.

14. Turn on the sample gas flow to the conditioning sample system and then open the
sample inlet valve.

15. Open the sweep valve slightly and adjust pressure regulator to 15 psig and the
flow meter to 2.0.

16. Allow twenty minutes for the analyzer to stabilize. The analyzer calibration can be
verified if calibration gas is available. If no calibration gas is available, the analyzer
may be operated using the factory calibration settings until calibration gas is
available.

Envent Engineering Ltd. Page 25 Revision 2.4

OPERATION & CONFIGURATION

Button

Description/Function

The 330S/331S H2S analyzer can be configured by using the display-button function
or by connecting the analyzer to a computer through USB.

Analyzer Display Interface

By using the analyzer's display, the user can only view and/or change certain
parameters set at the factory. The display is made up of a Graphic Display, four (4)
push-buttons and (8) LED's. Refer to Figure 10.

Figure 10. 330S Display (left) & 331S Display (right)

The Descriptions and Function of the display buttons and LED's are described in table
Table 4 & Table 5.

Bypass Used to inhibit all analyzer alarms to a non-alarm state and

sets the analog 4-40 mA output to 2 mA. The Bypass LED

illuminates when Bypass mode is enabled.
Scroll
Right [→]

Used to move the cursor to the right. Also used to SAVE

configuration adjustments when moved all the way to the

right of the screen.
Scroll Left
[←]

Used to move the cursor to the left. Also used to CANCEL

configuration adjustments when moved all the way to the left

of the screen.
Menu/Set Used to cycle through the menu options. Also used to

increase numerical values when making configuration

adjustments.

Envent Engineering Ltd. Page 26 Revision 2.4

Table 4. Display Button Description/Function

LED

Description/Function

Bypass Illuminates when the analyzer is in bypass mode.
LED A & B Red LEDs that can be used for different alarm configurations.

By default, these LEDs are left as spare.

Fault Illuminates when there is a fault in the Analyzer. Fault is used

for Board temperature, Sensor High/Low, Low H2S sensing
tape sensor, Pressure switch, etc.

LED 1 to 4 Green LEDs that can be used for different alarms or

conditions. By default, H alarm activates LED-1 and HH
alarm activates LED-2. (Refer to the LED Sticker on the
analyzer door on the inside (331S) or to the right side of the
blue chassis on of the XP enclosure).

Table 5. Display LED Description/Function

Envent Engineering Ltd. Page 27 Revision 2.4

CALIBRATION PROCEDURES

H2S Gas Calibration

Depending on the application, the 330S/331S H2S analyzer will require more or fewer
periodic calibrations. There is no specific time as to how often the H2S analyzer
should be calibrated. It will depend on the application, importance of accuracy for the
application, and how dirty or clean the environment and sample are. The following is
the calibration procedure for the 330S/331S H2S analyzer:

1. Source a calibration gas of H2S in balance of N2 regulated to 15 psi (check expiry
date). H2S concentration to be approximately 2/3 of full scale range or close to
the H2S alarm set point.

2. Press the bypass button and verify the "Bypass" LED illuminates (alarms will be
held in the non- alarm state).

3. Turn off all gas supplies to the analyzer and check that a sufficient amount of H2S
sensing tape is installed.

4. Press the "Menu/Set" button until "Mtr Run" is displayed. Press the right arrow
[→], the H2S sensing tape will advance for approximately 10 seconds.

Press the "Menu/Set" button until "mV" is displayed ("###mV"). If the mV reading is
1000mV (+100mV), proceed to the next step, otherwise re-zero sensor (Refer to "

5. Re-zero Sensor Procedure" on page 29).

6. Connect calibration gas to calibration port and turn the 3-way calibration valve
180°. The valve handle should be pointing towards where the gas bottle tubing is
connected to (Calibration Inlet).

7. Turn on sample inlet valve, ensure that the sample regulator is supplying 15psig
to the eductor (make sure there is suction from the eductor block). Adjust the flow
meter to 2.0. Wait until the H2S reading has stabilized (10 to 15 minutes).

8. With calibration gas applied, if H2S reading is satisfactory (+2% of analyzer full
range) skip to step 16, if H2S reading is not satisfactory a gain adjustment is
required, continue to step 9.

9. Press the "Menu/Set" button until the gain setting is displayed ("### Gain").

10. Calculate the new gain. New gain value should be within approximately 25% of
the gain installed at the factory.

Envent Engineering Ltd. Page 28 Revision 2.4

11. To adjust the gain setting such that the analyzer displays the correct H2S
concentration, press the right [→] and / or left [←] arrows until the cursor is
underneath the number you wish to change.

12. Adjust the number using the "Menu/Set" button (it will increase until "9" then will
cycle back through "0").

13. Save the new gain value by pressing the right arrow [→] until "Saved" appears or
discard by pressing the left [←] arrow until "Cancel" appears.

14. Allow the analyzer to complete two cycles using the new gain value. The H2S
reading should match the calibration gas concentration. Repeat step 10 if
necessary.

15. Return to sample gas flow using the 3-way calibration valve.

16. Set the sample gas pressure to 15 psig and set the flow meter to 2.0.

17. Disconnect the calibration gas supply.

18. After waiting 10 to 15 minutes confirm the analyzer reads below the H2S alarm
set points.
Remove the analyzer from bypass mode by pressing the bypass button. Verify

the "Bypass" LED turns off.

Alarms are armed after removing the bypass mode.

Re-zero Sensor Procedure

1. Press the bypass button and verify that the "Bypass" LED illuminates.

2. Turn off sample gas flow using sample inlet valve.

3. Press the "Menu/Set" button until "Mtr Run" is displayed. Press the right arrow
[→], the H2S sensing tape will advance for approximately 10 seconds.

4. Remove the sensor cover.

5. Press the small pushbutton on the sensor block located on the lower left side next
to the wire connector.

• The sensor block will implement a "re-zero" procedure, indicated by a lit, red
LED.

• When the "re-zero" procedure is complete the LED light will turn green.

6. Initiate another motor run (Step 3).

7. Press the "Menu/Set" button until "### mV" is displayed.

• Value should be 1000mV (+100mV)

8. Put on sensor cover.

9. Turn on sample gas flow using sample inlet valve.

10. Set the gas pressure to 15 psig and the flow meter to 2.0.

Envent Engineering Ltd. Page 29 Revision 2.4

11. Confirm the analyzer reads below the H2S alarm set points.

12. Remove the analyzer from bypass mode by pressing the bypass button. Verify
the "Bypass" LED turns off.

Alarms are armed after removing the bypass mode.

Envent Engineering Ltd. Page 30 Revision 2.4

MAINTENANCE

The 330S/331S H2S analyzer will provide reliable service with very little attention. If
the analyzer is kept clean there should be no requirement to recalibrate from factory
gain settings. However, regular check-up (at least every three months) will ensure that
the analyzer is operating to specifications.

• Ensure that the H2S sensing tape take-up and feed reels are tight

• Ensure that the flow meters, humidifier tubing and sample chamber tubing are free

of liquid or particulate contamination. If the sample conditioning system is flooded
with liquid, refer to "Sample Conditioning System Cleaning Procedure" on page 32.

• Ensure there is enough H2S sensing tape, especially if a low H2S sensing tape
sensor is not installed. Refer to "H2S Sensing Tape Change Procedure" on page

31.

• Check the sample conditioning filter(s) every time the H2S sensing tape is
replaced. Replace the filter(s) as required.

H2S Sensing Tape Change Procedure

Figure 11. 331S & 331SDS Sensing Tape Change

Procedure (Same as the 330S & 330SDS models)

Envent Engineering Ltd. Page 31 Revision 2.4

Sample Conditioning System Cleaning Procedure

During start-up or plant upset situations, the 330S/331S H2S analyzer may become
contaminated with amine or hydrogen sulfide scavenger solution. This may cause the
analyzer to read low (this can be determined at calibration). If the analyzer reads low,
it will require incremental increases in the gain to maintain calibration. Please refer to
factory calibration sheet for factory set gain factor. The scavenger solution is water
soluble and therefore is relatively easy to clean.

Material List

Cleaning Kit Part Number: 330900

• Alconox RBS Solid, powdered precision cleaner w/ MSDS (2.5 tbsp)

• 330079 – Rear window and gasket

• MIF-225-PP – Small nipple (x2)

• MIF-32-PVC – Grey nipple

• MIF-32-PP – Big nipple

• MIF-24-PVC – Humidifier replacement tube fittings (x2)

• MIP-4 Humidifier replacement plug

• 06349-40 – Black 1/8" male/female elbow

• LT-2-4 (1/4" x 11") – Tubing for sample chamber to humidifier

• LT-2-4 (1/4" x 10") – Tubing for flow meter to humidifier

• LT-3-5 (3/16" x 10") – Tubing for sample chamber to vent block

• PFA (24") – Tubing for flowmeter to bulkhead

Do not use solvents, brake cleaners, soaps, detergents or rubbing alcohol to clean up
analyzer or sample system.

Procedure

1. Mix a 1% (2-1/2 tbsp per gallon) of Alconox in warm water

2. Sample line tubing

• Shut off flow at the sample point prior to sample conditioning system

• Flush the sample line and components with cleaning solution

• Rinse with fresh water

• Flush with isopropyl alcohol

• Dry with clean, dry instrument air or gas

3. Sample conditioning system – Take pictures of SCS before disassembling

• Remove filter elements from filter housings and discard

Envent Engineering Ltd. Page 32 Revision 2.4

• Remove all sample conditioning system components and soak in cleaning
solution

• Ensure valves are fully open when cleaning

• Flush sample components with fresh water

• Rinse with isopropyl alcohol

• Blow dry with clean compressed air or fuel gas

• If the clear Vinyl tubing appears discolored, replace the tubing.

• Nafion tubing on humidifier should be replaced if it appears contaminated

Disassembly of the pressure regulator and solenoids in the field is not advised.
Consult the factory if the regulator or solenoid appears contaminated.

4. Re-assemble Stainless Steel Tubing to analyzer according to analyzer drawing,
refer to pictures taken before disassembling or refer to drawing package.

5. Once sample conditioning system has been re-assembled, apply calibration gas to
the analyzer. Refer to "H2S Gas Calibration" on page 28.

Envent Engineering Ltd. Page 33 Revision 2.4

TROUBLESHOOTING

Problems

Possible

Reasons

Possible Solutions

H2S Readings Issues

Erratic H2S
Readings

Pressure in building moving up

Sample vent/Eductor either

Analog input 2 jumper

Sensor block fault Re-zero sensor block. Refer to "Re-zero

Sensor did not zero on white

Regulator not maintaining 15

Trigger slide and H2S sensing
tape not seated properly

and down from fan, exhaust or
wind

blocked or frozen

removed

H2S sensing tape

psig (Changing flow rate to
analyzer)

Continued on next page

Ensure trigger slide and H2S sensing tape
are seated in the groove of the sample
chamber.
The eductor should counteract this effect,
however, the eductor may be plugged or
vent blocked. Check there is no blockage
and that all vent tubing and fitting are 316
stainless steel, sized 3/8'' or larger on a
downward slope.
Check there is no blockage on the vent
and/or eductor. Check for vacuum in
Eductor block. Vent tubing and fittings
should be 316 stainless steel 3/8'' or larger
on a downward slope. Possible heat trace
required.
Re-install jumper in Analog Input across
(+4-20 & -4-20) on the controller board.

Sensor procedure" on page 29.
Check for green status led on sensor block
once procedure is done & proper mV on
white H2S sensing tape.
Check the H2S Sensing tape, if not properly
installed, refer to "H2S Sensing Tape
Change Procedure" on page 31 or on
sticker in the analyzer's door.

Perform a motor Run: Display>Press Menu
Button until "MTR Run">Press right button.
This will activate the motor and move the
H2S Sensing tape for a few seconds.
Re-zero sensor block if necessary. Refer to
"Re-zero Sensor procedure" on page 29.

Replace Regulator, Consult Envent
Engineering Ltd.

Envent Engineering Ltd. Page 34 Revision 2.4

H2S Readings Issues (Cont’d)

Problems

Possible Reasons

Possible Solutions

Contaminants in sample

chamber

Clean sample chamber, aperture and
window; replace if required. Contact Envent
Engineering Ltd for replacement assistance.

Contaminants or liquid carry

over in sample conditioning
system

If contaminants or liquid has carried over
the sample system, refer to page 32.

Humidifier leaking Humidifier needs to either be repaired or

replaced. Consult Envent Engineering Ltd.

Possible high pressure in flare

Install a higher rated check valve.

line (Dilution option only)

Slow response Aperture in chamber not

optimized for required range

Consult "Aperture Strip" on page 19 for
aperture size and contact Envent
Engineering Ltd to order aperture and for
assistance to install new aperture and re­calibrate analyzer. Refer to "H2S Gas
Calibration" on page 28.

Contaminants or liquid carry

over in sample conditioning

system
Higher than
Expected

Sample vent/Eductor either

blocked or frozen
Readings

If contaminants or liquid has carried over
the sample system, refer to page 32.

Check there is no blockage on the vent
and/or eductor. Check for vacuum in
Eductor block

Vent tubing and fittings should be 316
stainless steel 3/8'' or larger on a downward
slope. Possible heat trace required.

Contaminants in sample

chamber

Clean sample chamber, aperture and
window; replace if required. Contact Envent
Engineering Ltd for replacement assistance.

Aperture out of place or not

optimized for required range

Remove the sample chamber, unscrew the
sensor block and check that the aperture is
not out of place. Consult "Aperture Strip" on
page 19 for aperture size and "H2S Gas
Calibration" on page 28. Contact Envent
Engineering Ltd to order aperture (if
applicable) and for assistance to install new
aperture and re-calibrate analyzer.

Continued on next page

Envent Engineering Ltd. Page 35 Revision 2.4

H2S Readings Issues (Cont’d)

Problems

Possible

Reasons

Possible Solutions

Sensor/ sensor wire failure Re-zero the sensor block. Refer to "Re-zero

Sensor procedure" on page 29.
If procedure fails, sensor or sensor wire
may require replacement.

Gain set too high Gain is too high for the current setup. Re-

calibrate analyzer and refer to current gain
(from factory). The difference between
factory gain and new gain should not be
greater than +/- 2%. If necessary, do a gas
calibration. Refer to "H2S Gas Calibration"
on page 28

Higher than required

pressure/flow
Dilution canister tubing loose

(Dilution option only)

Adjust pressure regulator to 15psig and flow
meter to "2"
Tubing inside the canister leaking. Open
canister (follow all safety procedures to
bleed out all high H2S level concentrations)
and re-connect the tubing to the fittings on
canister lid. Contact Envent engineering Ltd
for replacement if required.

Total Sulfur's Hydrogen flow

was decreased at the flow

meter (Total Sulfur option only)

The flow of hydrogen being mixed with
sample gas has been decreased. Either the
hydrogen bottle is empty, or the flow was
decreased through the flow meter knob.

Adjust back to appropriate flow rate.
Lower than
Expected
Readings

Leaks in the sample system
causing lower readings

Do a leak check on the sample system and

humidifier. Use Snoop to detect the

possible leaks in the system.
Flow is too low Make sure that the flow of sample gas

coming into the analyzer is set to "2" (83.63

cc/min) at the flow meter.
Gain set too low Gain is too low for the current setup. Re-

calibrate analyzer and refer to current gain

(from factory). The difference between

factory gain and new gain should not be

greater than +/- 2%. If necessary, do a gas

calibration. Refer to "H2S Gas Calibration"

on page 28

Continued on next page

Envent Engineering Ltd. Page 36 Revision 2.4

H2S Readings Issues (Cont’d)

Problems

Possible Reasons

Possible Solutions

Not using the humidifier or

humidifier leaking

A humidifier is not necessary if the sample

gas inlet is already humidified. If the sample

gas inlet is dry, a humidifier must be used.

Make sure the humidifier unit is placed and

installed correctly. Please refer to

"Humidifier Unit" on page 19.

Humidifier Leaking: it needs to either be

repaired or replaced. Consult Envent

Engineering Ltd.
Sensor/ sensor wire failure Re-zero the sensor block. Refer to "Re-zero

Sensor procedure" on page 29.

If procedure fails, sensor or sensor wire

may require replacement.
Dilution Instrument air or

carrier gas flow was increased
(Dilution option only)

If the instrument air or the carrier gas is

increased in flow, the readings will be lower.

Make sure to keep a constant flow and

pressure for the instrument or carrier gas.
Hydrogen flow has been

increased (Total Sulfur option
only)

Lower the hydrogen flow to the specified on

the flow meter.

Envent Engineering Ltd. Page 37 Revision 2.4

H2S Sensing Tape Issues

Problems

Possible Reasons

Possible Solutions

Tape does not
advance

No tension on take up reel Check setscrew in take up reel collars, if

loose; tighten up with a 1/16" hex key. Do a

manual advance on H2S sensing tape. To

do a motor run: Display>Press Menu Button

until "MTR Run">Press right button.

This will activate the motor and move the

H2S Sensing tape for a few seconds.
Tape breaking High liquid content in sample

gas

Genie probe and additional filtration may be

required in sample conditioning system.

Feed wheel not spinning freely Dust and refuse build up between feed

wheel and chassis. Requires removal and

cleaning of chassis.
Tape cover wheels pressing

against H2S sensing tape

H2S sensing tape cover wheel became

warped. Needs to be flattened to not

contact tape when on feed wheel bolt. If

replacement needed, consult Envent

Engineering Ltd.
Trigger slide not seated

properly
Overlapping
Stains

This is normal in the 1st 1/4 of

a new H2S sensing tape. It

should not cause any reading

problems.

Ensure trigger slide is seated in groove of
sample chamber.
If it is causing reading problems, the "stop
threshold" can be modified from 1,000,000
to 500,000. Please consult Envent
Engineering Ltd before proceeding with this

change.
Excessive H2S
sensing Tape
consumption

Sample vent either blocked or
frozen

Check there is no blockage on the vent

and/or eductor. Vent tubing and fittings

should be 316 stainless steel 3/8'' or larger

on a downward slope. Possible heat trace

required.
Contaminants in sample

chamber

Clean sample chamber. Replace aperture

and window if required. Contact Envent

Engineering Ltd for replacement and

assistance.
H2S Sample inlet constantly

being out of range from
original analyzer intent

If the H2S sample inlet is greater than the

range of the analyzer, the tape will be

consumed after than in normal operation.
Aperture out of place Take out the sample chamber, unscrew the

sensor block and check that the aperture is

not out of place. If so, refer to "Aperture

Strip" on page 19 for aperture size and "H2S

Gas Calibration" on page 28.

Continued on next page

Envent Engineering Ltd. Page 38 Revision 2.4

H2S Sensing Tape Issues (Cont’d)

Problems

Possible Reasons

Possible Solutions

Sensor/ sensor wire failure Try re-zeroing the sensor. Refer to "Re-zero

Sensor procedure" on page 29.

If procedure fails, Sensor or sensor wire

may require replacement.
H2S sensing
Tape coming

Trigger slide not seated
properly

Ensure trigger slide is seated in groove of

sample chamber
out of sample
chamber/trigger
slide

Electronics Issues

Fault LED
(Sensor High)

Incorrect zeroing Make sure the H2S Sensing tape is

installed properly and do a motor run.

To do a motor run: Display>Press Menu

Button until "MTR Run">Press right button.

This will activate the motor and move the

H2S Sensing tape for a few seconds. The

alarm should clear.
Faulty Sensor Sensor needs to be replaced. Contact

Envent Engineering Ltd for replacement.
Fault LED
(Sensor Low)

Sensor did not zero on white
H2S sensing tape because
H2S sensing tape came out of
sample chamber slot

Re-install H2S Sensing tape. Refer to "H2S

Sensing Tape Change Procedure" on page

31 or on sticker in the analyzers door.

Re-zero sensor block. Refer to Refer to

"Re-zero Sensor procedure" on page 29.

Sensor/ sensor wire failure Re-zero the sensor block. Refer to "Re-zero

Sensor procedure" on page 29. If procedure

fails, sensor or sensor wire may require

replacement.

Continued on next page

Envent Engineering Ltd. Page 39 Revision 2.4

Electronics Issues (Cont’d)

Problems

Possible Reasons

Possible Solutions

IS Barrier failure (For 330S

analyzer series only)

Contaminants in sample

chamber

IS Barrier may need replacement. Consult

Envent Engineering Ltd.

Clean sample chamber. Replace aperture

and window if required. Contact Envent

Engineering Ltd for replacement and

assistance.
Fault LED (Low
H2S sensing
Tape)

New H2S sensing tape is
required

H2S Sensing tape requires change

(Average of 2 to 3 days left, from the

moment alarm goes off, for the tape to be

completely used up). Refer to "H2S Sensing

Tape Change Procedure" on page 31 or on

sticker in the analyzers door.
Low H2S sensing tape sensor

failure

If the alarm does not clear once a new H2S

sensing tape is installed, the low H2S

sensing tape sensor or its wires have failed

and need to be replaced. Consult Envent

Engineering Ltd to order a replacement.

Low H2S sensing Tape Sensor Part #:

330046A
Fault LED (Low
Pressure)

Pressure of sample gas is
lower than setpoint of pressure
switch (factory set to 10 psi
descending)

Inspect the sample inlet upstream to

troubleshoot the problem.

Pressure switch failed If pressure is above 10 psi and alarm

continuous, the pressure switch setpoint

might have changed. Set back to 10 psi

descending. Also, check pressure switch

wiring

If the problem persists, pressure switch

might need replacement. Contact Envent

Engineering Ltd.
Pressure regulator failed The problem might be coming from the

pressure regulator. Troubleshoot and

consult Envent Engineering Ltd.
Fault LED
(Oven Fail)

Fuse not installed. Fuse for furnace does not come installed in

the controller board. Please check spare

fuse bag and install fuse.
Oven not working properly Oven failed and temperature has dropped

below the optimal temperature. Please

consult Envent Engineering Ltd.
Blank Display Contrast needs adjustment Change contrast by turning the

potentiometer in the display board.

Continued on next page

Envent Engineering Ltd. Page 40 Revision 2.4

Electronics Issues (Cont’d)

Problems

Possible Reasons

Possible Solutions

Analyzer not
communicating
with PC

Multiple reasons could be
causing the analyzer to not
communicate properly with the
PC.

Check that the analyzer is ON.

Check that the communication cable is

properly connected.

If the software application was open before

connecting the communication cable from

the analyzer to the computer, close the

software and re-open it. Try again and

enable communication.
Analyzer not
turning ON

Blown fuse Check fuse in the controller board. Replace

if required.
Controller board Malfunction Consult Envent Engineering Ltd for a

controller board replacement.
Not using the appropriate

voltage rating

Make sure to use the appropriate voltage to

power the analyzer. DC controller boards

can be powered with 12 - 24 VDC and AC

controller boards can be powered with 110

to 240 VAC. Keep in mind that if solenoids

are controlled by the controller board, the

voltage must match the solenoids voltage

rating.
Red LED on
Sensor Block

Sensor block fault Re-zero sensor block. Refer to "Re-zero

Sensor procedure" on page 29.

Check for green status led on sensor block

once procedure is done. If sensor LED

stays red, consult Envent Engineering Ltd

for a replacement.
Wiring not done properly Make sure the wiring is done correctly.

Analog Outputs
(4-20 mA) not
working

Not using an external power
supply

The analog outputs in the controller board

are loop powered and not self-powered

unless AO boards were installed as per

customer request. If AO boards were not

requested, an external power supply must

be used. Refer to "Analog Outputs" on page

16 to see different wiring options.

Continued on next page

Envent Engineering Ltd. Page 41 Revision 2.4

Electronics Issues (Cont’d)

Problems

Possible Reasons

Possible Solutions

Problems

Possible Reasons

Possible Solutions

The system variable for output

has been modified.

Not coming out

Alarms are latched If alarms are latched, they need to be

of alarm

The analyzer is actually in

alarm

Sample Conditioning System Issues

By factory configuration, the analog outputs

(1 & 2) are configured to output based on

H2S Sample 1. Make sure that if they are

modified, that the right system variables are

selected.

acknowledged. Go to the display> cycle

through until "ACK" is reached> press the

right button to acknowledge all latched

alarms.

To deactivate the latching on any alarm,

use the ICE software, and connect to the

analyzer and de-select latching on any

alarm that is latched.

Make sure the alarm setpoint values are as

desired and that the analyzer is below (or

above – like temperature setpoint) those

setpoint values.

Liquid Carried
over in SCS

Regulator not
maintaining 15

Sample too wet for current
conditioning sample system.

Problems with the Regulator

(over pressured)
psi (erratic H2S
readings)
Liquid carried over into

regulator
Problems with the (50 psi)

sample pre-regulator at the

sample point.

Continued on next page

If a one-time occurrence: Cleaning required
for sample system, refer to "Sample
Conditioning System Cleaning Procedure"
on page 32.

If more than one time occurrence: Sample
conditioning system may need a system for
wet/dirty sample gas (extra filters set as
coalescing, add liquid float stops, etc.).
Consult Envent Engineering Ltd.
Replace Regulator, Consult Envent
Engineering Ltd.

Consult Envent Engineering Ltd.

Heated regulator may be required if liquid
hydrocarbon carry over is present at the
pre-regulation sample.

Envent Engineering Ltd. Page 42 Revision 2.4

Sample Conditioning System Issues (cont’d)

Problems

Possible Reasons

Possible Solutions

Problems

Possible Reasons

Possible Solutions

Pressure gauge
not working
Flowmeter not
working
Frozen
humidifier

Humidifier
leaking liquid

Change gain
more than +/­25% from
original gain
after calibration

Over pressured gauge Replacement is required. Consult Envent

Engineering Ltd for replacement.
Liquid carried over into
flowmeter
Analyzer is being exposed to
temperatures below 0 degress

Consult Envent Engineering Ltd.

Do not expose analyzer to temperatures

below 0 degress °C or - 2 degress °C
°C (or - 2 degress °C if 5%
acetic acid is used)

The humidifier body cracked ­Could be due to extreme

A replacement may be required. Consult

Envent Engineering Ltd for a replacement.
temperature changes.

Calibration Issues

Not using the right calibration
bottle

Make sure the calibration bottle is within

analyzer range. It is recommended that

calibration gas used is close in value to

where the alarm setpoint values need to be

(for more accuracy).

Envent Engineering Ltd. Page 43 Revision 2.4

APPENDICES

Recommended Spare Parts List

Part Number Quantity Description
330053 1 Eductor Block
330063
(330063D for SDS)
330079 2 Rear Window & Gasket
330100 - 330110 1 or (2

330130 1 4 liter Containers of Acetic Acid
330133XS 12 300' Lead Acetate Tape (H2S Sensing

330406 1 Box of 10 Micro Filter Glass Fiber Element

330423 2 13'' Chubby Quartz Tube (Total Sulfur

3300429 1 TS Ceramic Heater (Total Sulfur option

330431 4 Kalrez O-rings (Total Sulfur option only)
330900 1 Tubing, Cleaner, Fittings Maintenance Kit

1 Humidifier Rebuild kit c/w Elbows, Nafion

Tube, ftg

Aperture Strip (Associated to measurement

for SDS)

range)

Tape)

12/19-57-50CSK

option only)

only)

Envent Engineering Ltd. Page 44 Revision 2.4

Chico A Sealing Compound: For sealing fittings in Hazardous Locations

Envent Engineering Ltd. Page 45 Revision 2.4

Safety Data Sheet for H2S Sensing Tape

Envent Engineering Ltd. Page 46 Revision 2.4

Envent Engineering Ltd. Page 47 Revision 2.4

Envent Engineering Ltd. Page 48 Revision 2.4

Envent Engineering Ltd. Page 49 Revision 2.4

Envent Engineering Ltd. Page 50 Revision 2.4

Risk Assessment - Safety Information

Hydrogen Sulfide Properties

Physical State

Usually encountered as a gas

Hydrogen Sulfide Quantities and Health Effects

H2S Exposure

Possible health Effects

Color Colorless - No visible sign of H2S to warn you of its presence
Odor Characteristic smell of rotten eggs at 0.5 ppb; paralyzes the olfactory nerve

around 100 ppm

Vapor Density Heavier than air (1.19 compared to 1.0 for air)

> In gas mixtures, it will be present wherever the gas mixture is found
> Gas mixtures may be heavier or lighter than air, depending upon their vapor
density and temperature compared to the ambient atmosphere (i.e. usually air)
> In its pure state, or as a high proportion of a gas mixture, it may flow or settle
into low-lying areas, such as pits, trenches and natural depressions

Flammability Flammable

Flammable at 4.3 - 46 percent vapor concentration in air, by volume

Burns with a blue flame and gives off Sulphur dioxide (SO2) gas SO2 is also

hazardous and irritates the eyes and the respiratory system
Solubility Soluble in water and oil, solubility is inversely proportional to fluid temperature
Common
Locations for H2S

Piping systems, pipelines, wellheads or wellbores, vessels, production

facilities, tanks, pits and low spots, confined or enclosure spaces, shacks or

buildings, bermed or diked area, sour spills.

Table 6. Hydrogen Sulfide Properties

Less than 1 ppm you can smell it
10 ppm > No known health effects for most people

> For 10 ppm or less, the exposure limit is 8 hours - Check your local legislation
as they vary.
> For 15 ppm, the exposure limit is 15 min with 60 minutes breaks. Check your
local legislation as they vary.

20-200 ppm > Eye and respiratory tract irritation and loss of smell

> Headache and nausea - loss of smell after 2 - 5 min
> Respiratory Protection is required beyond this level such as SCBA (Self­contained Breathing Apparatus) and SABA (Supplied Air Breathing Apparatus)

200 - 500 ppm > Above effects, but sooner and more severe

> Loss of breathing and death in 30 min to 1 hour

500 - 700 ppm > Affects the central nervous system

> Rapid unconsciousness, cessation of breathing, and death
700 ppm and
above

> Immediate loss of consciousness

> Permanent brain damage and death in a few minutes even if removed to fresh

air at once

Table 7. Hydrogen Sulfide Quantities & Health Effects

Envent Engineering Ltd. Page 51 Revision 2.4

Risk Assessment

Hazard

Identification -

Who might

Health and Safety

Hazard Control Recommended

Task

Maintenance:
Changing the H2S
sensing Tape
(Acetate Tape)

Maintenance:
Changing filter in
SCS

be harmed

Risks
by this
hazards

Operator(s) Long term exposure

(through skin and

inhaling) could

potentially cause

cancer and other

health problems - Not

an immediate safety

risk

Operator(s) Potential safety risk -

release of gases at a

high pressure level

can cause serious

injuries

Due to the long term health
effects of Lead which is contained
in the H2S Acetate tape, the
operator is recommended to wear
gloves & mask when handling the
tape. If gloves where not worn,
hands must be properly washed
with soap and water

As an overall practice when doing
maintenance into an H2S
analyzer, the operator should
carry a personal H2S monitor,
wear a hard hat, hearing
protection (if applicable), safety
glasses, hand protection, steel
toed boots. Depending on the
location of the H2S analyzer,
appropriate breathing device
might be required such as SCBA
(Self-contained Breathing
Apparatus) and SABA (Supplied
Air Breathing Apparatus)
Due to the fact that the filter is
located before the pressure
regulator, the operator could be
dealing with pressures up to 3600
PSI. The operator must isolate
the sample system before
changing the filter

As an overall practice when doing
maintenance into an H2S
analyzer, the operator should
carry a personal H2S monitor,
wear a hard hat, hearing
protection (if applicable), safety
glasses, hand protection, steel
toed boots. Depending on the
location of the H2S analyzer,
appropriate breathing device

Envent Engineering Ltd. Page 52 Revision 2.4

H2S Exposure
(Atmosphere)

H2S Exposure
(Leakage ­Overpressure)

Operator(s) Potential safety and

health risk - Death -

Consult Table

Hydrogen Sulfide

Quantities and Health

Effects.

Operator(s) Potential safety and

health risk - Death -

Consult Table

Hydrogen Sulfide

Quantities and Health

Effects.

might be required such as SCBA
(Self-contained Breathing
Apparatus) and SABA (Supplied
Air Breathing Apparatus)
For atmospheres where there is
H2S, depending on the levels and
company policy, the operator
must wear the appropriate
equipment before servicing an
H2S analyzer

As an overall practice when doing
maintenance into an H2S
analyzer, the operator should
carry a personal H2S monitor,
wear a hard hat, hearing
protection (if applicable), safety
glasses, hand protection, steel
toed boots. Depending on the
location of the H2S analyzer,
appropriate breathing device
might be required such as SCBA
(Self-contained Breathing
Apparatus) and SABA (Supplied
Air Breathing Apparatus)
In case of a leakage, follow
company's health and safety
policies on how to deal with an
H2S leak. Depending on the
application and location of the
H2S analyzer, the operator might
have to use the proper breathing
equipment

As an overall practice when doing
maintenance into an H2S
analyzer, the operator should
carry a personal H2S monitor,
wear a hard hat, hearing
protection (if applicable), safety
glasses, hand protection, steel
toed boots. Depending on the
location of the H2S analyzer,
appropriate breathing device
might be required such as SCBA
(Self-contained Breathing

Envent Engineering Ltd. Page 53 Revision 2.4

Apparatus) and SABA (Supplied

Air Breathing Apparatus)
Flooding the
Sample system &
analyzer

Operator(s) Not immediate safety

and health concern

If the analyzer is flooding, the

analyzer needs to be immediately

isolated, turned off and cleaned.

Refer to "Sample Conditioning

System Cleaning Procedure" on

page 32

As an overall practice when doing

maintenance into an H2S

analyzer, the operator should

carry a personal H2S monitor,

wear a hard hat, hearing

protection (if applicable), safety

glasses, hand protection, steel

toed boots. Depending on the

location of the H2S analyzer,

appropriate breathing device

might be required such as SCBA

(Self-contained Breathing

Apparatus) and SABA.
Voltage hazards Operator(s) Immediate safety and

health risk.

It is important that the operator is

trained on handling the analyzer

when it is on. The analyzer does

not need to be off when it goes

into maintenance. However, it is

very important that the operator is

aware of the danger of an electric

shock
TS Enclosure heat Operator(s) Medium safety risk The inside of the Total Sulfur

Enclosure can get up to 900 °C,

however, the outside walls will

only reach approximately 150 °C.

Do not touch surface of the TS

enclosure when operating. If the

TS enclosure needs to be

serviced, allow 1 hour after

powering down the analyzer to

cool down
Electrostatic
hazard - Explosion
hazard

Operator(s) Immediate safety and

health risk.

Electrostatic Hazard – Backpan

and Certification nameplate must

be cleaned only with a damp cloth

to prevent static charging hazard

which could result in an explosion

Table 8. Risk Assessment

Envent Engineering Ltd. Page 54 Revision 2.4

This document has been continuously improved and revised over time; see the table below for

Revision No.

Revision Date

Revision Description

revision (rev) information.

0 15 April 2016 New and Updated 330S-DS / 331S-DS Manual

1.0 12 Oct 2016 Updated information on analysis cycle + Fix minor mistakes

2.0 19 May 2017 Section updates on manual based on 61010 Standard
updates

2.1 28 Dec 2017 Updated Standard section to 61010 Standards

2.2 04 Sep 2017 Fixed Modbus Registry

2.3 04 Dec 2018 Fixed grammar mistakes and USA phone number

2.4 08 Jan 2019 Improvement of the overall customer manual – Software
section will now be in a separate manual

Decimal increases on revision numbers (E.g. Rev 1.0 to Rev 1.1) on this user manual means that
content changes will not affect or contradict Intertek certification documentation, thus the notified body
does not need to be informed of the changes; for instance, improving writing or layout. A full unit
change (E.g. Rev 1.0 to Rev 2.0) will mean that the content changes must be communicated and
updated to the notified body.

For further information, or a copy of our most recent operating manual, please visit us at www.envent-

eng.com. Envent Engineering Ltd reserves the right to change product design and specifications at any

time without prior notice

Envent Engineering Ltd. Page 55 Revision 2.4