YOKOGAWA ZS8 User manual

User’s
Manual Model ZS8
Flameproof
Zirconia Oxygen Analyzer
IM 11M7A3-01E
IM 11M7A3-01E
6th Edition
TM

<PREFACE> i
IM 11M7A3-01E
tPREFACE
This instruction manual describes the handling of the ameproof zirconia oxygen analyzer.
To ensure safe operation and maximum performance of ameproof zirconia oxygen analyzer,
read this manual carefully before using it.
Items to which attention needs to be paid with regard to the handling of the ameproof zirconia
oxygen analyzer, are shown in this manual in the form of
WARNING and CAUTION.
These items must be read before it is put in operation.
WARNING
Items involving serious accidents due to incorrect handling of ameproof zirconia oxygen
analyzer.
CAUTION
Items involving injury, damage to device or physical damage.
WARNING
• Power source
Before the power for the unit is turned ON, make sure that the power voltage conforms to
the power supply voltage.
• Earthing
Before turning ON the power for the unit, be sure to earth the unit to prevent electric shocks.
• Necessity of earthing
Neither cut o󰀨 the internal (or external) earth cable of the unit, nor disconnect the earth
terminal, otherwise, it causes a hazard to human body.
• Defect in function
If protective functions such as earthing, fuse, etc. seem to be defective, do not operate the
unit. Before operating the unit, check to make sure that the protective functions are not
defective.
• Fuse
To prevent re accidents, be sure to use the specied type of fuse. Do not attempt to use
other types of fuses. Care should be taken not to short the fuse holder.
When it becomes necessary to replace fuse, turn OFF the power switch and disconnect the
unit from the main power source.
• Do not touch the inside.
The unit has high-voltage circuits. Do not touch the inside of the unit when the power is
ON. Do not replace or repair the unit by yourself. Contact our service-man or authorized
engineer.
• External connection
The unit must be earthed before connecting it to measuring object or external control circuit.
• Prohibition of modication or mounting of additional parts in unit
Do not attempt to modify or mount additional parts in the unit, otherwise, it a󰀨ects the safe
operation or damages the unit.
Media No. IM 11M7A3-01E 6th Edition: Nov. 2019
All Rights Reserved Copyright © 1996, Yokogawa Electric Corporation

<PREFACE>
ii
IM 11M7A3-01E
WARNING
• Before opening the cover of the ZS8C converter, remove power and make sure of non-
hazardous (*) atmospheres.
• When the ambient temperature of the converter exceeds 50ºC, use wire resistant to 70ºC or
greater for external wiring.
(*) The text plate says "Open circuit at non-hazardous location before removing cover," since the internal energy of the ZS8C
converter decreases under the specied value.
The denition of the non-hazardous area is followed by the description in the Users Guide to Installing Flameproof
Electrical Apparatus at Plants, issued by the Technology Institution of Industrial Safety, Japan: As a non-hazardous area
is considered a place where no occurrence of explosive gas atmospheres is guaranteed by the foreperson and conrmed
by a written document. Therefore, if non-hazardous area is secured, it is allowed to open the cover in the eld.
• Before opening the cover of the ZS8D detector, remove power and allow the detector to
stand at least 40 minutes.
• When the ambient temperature of the detector exceeds 30ºC, use wire resistant to 70ºC or
greater for external wiring.
• The detector cannot be used except in mixed gases composing air or mixed gas with
oxygen concentration lower than air, or combustible gas or vapor.
CAUTION
• Choose a suitable location for installation.
The unit should be installed in a place of normal temperature and humidity where there
is less change in temperature and the unit is not exposes to strong radian heat and direct
sunlight.
Since the unit is designed for indoor use, choose a place free from direct wind/rain or use a
suitable case cover.
• Do not use the unit in a place with vibration.
• Cleaning of instrument
Do not use benzine or thinner for cleaning, as it deforms or cracks the unit.
• Use in good atmosphere
The unit should be used in a clean place free from corrosive or combustible gas.
• Caution to electric shocks
The earth cable must be earthed to prevent electric shocks.
• Key operation
Do not operate the keys on the front of the instrument with a sharp-end object.

<PREFACE> iii
IM 11M7A3-01E
Introduction
The EXA OXY Model ZS8 Flameproof Oxygen Analyzer is used for combustion status monitoring
or control in processes which require combustion control in every eld. There are several types
of EXA OXY detectors, and the auxiliary equipment needed for optimum measurement are also
available. Also, devices for automating calibration are available. As stated above, since many
kinds of equipment and devices are available for this EXA OXY analyzer, select the appropriate
devices and construct the optimum measuring system when this model is to be used.
This manual describes the installation, operation, inspection and maintenance of almost all of the
equipment related to EXA OXY systems. Read the instructions thoroughly before you handle the
equipment but you may skip sections on equipment which is not included in your system.
The types of equipment described in this manual and the contents for each one are as shown
below.
Types of Equipment Described in This Manual and Contents for Each One
Model Product Name
Items Described in the Manual
Speci
cations
Instal
lation Operation Mainte
nance CMPL
ZS8D-L General-purpose detector     
ZS8D-H High-temperature detector     
ZS8C Converter     
ZS8P-H Probe adaptor   
ZA8F Flow setting unit   
—Ejector assembly
(Part No.: K9292VA/VB/WA/WB)   
—Calibration gas unit case (Part
No.: E7044KF)  
CAUTION
There are two types of general-purpose detectors: one which vents to the outside of a furnace
the mixed gases of a sample gas suctioned in by the ejector and ejector air, and another which
returns mixed gases to the furnace. High-temperature detectors all vent to the outside of a
furnace. Vent the mixed gas of a sample gas and ejector air to a place where no safety problems
will occur (the venting owrate should be 40 to 50 l/min). A general-purpose detectors may
be a “return to the furnace” type. A return pipe is provided as standard. However, be cautious
in returning gas to a furnace because air is blown into the furnace. The normal ow rate of
Netwrining gas is approximately 3 l/min to 5 l/min.

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IM 11M7A3-01E
This manual takes the following conguration. A brief description of each chapter and the
chapters to be referred to for installation, operation and maintenance are given.
Chapter conguration of the manual and items to be referred to.
Chapter Conguration of This Manual and Items to be Referred to
Chapter Brief description
For reference to
Instal
lation Operation Mainte
nance
1. General System component units for the EXA OXY
zirconia oxygen analyzer and system
conguration are shown.

2. Installation Installation procedures for each unit are
described.
3. Piping Piping procedures are explained for four
standard system congurations.
4. Wiring Wiring procedures are given for each system,
such as power supply wiring, output signal
wiring, etc.
5. Components
and their
functions
Names and major functions of components of
main units in the manual are illustrated.
6. Operation Basic procedures are presented to put the EXA
OXY analyzer into the operation status.
7. Operating
keys and
display of
converter
Converter key operations and items related to
the display are detailed.
8. Calibration Calibration procedures carried out as
necessary are described.
9. Inspection
and
maintenance
Inspection items to maintain the EXA OXY
analyzer performance and procedures for
replacing deteriorated parts and components
are described.

10. Trouble
shooting
Countermeasures when the system fails and/or
disposition for failure are shown.
Customer
maintenance
parts list
Parts that can be freely replaced by the user if
damaged are illustrated for each unit. 
: Thoroughly read the instructions and do work after fully understanding the contents.
: Before actual work, rst read the description or refer to it if necessary.
: It is recommended that you read the description.
nTrademark Notices
• EXA OXY is a trademark of Yokogawa Electric Corporation.
• All other company and product names mentioned in this user’s manual are trademarks or
registered trademarks of their respective companies.
• We do not use TM or ® mark to indicate those trademarks or registered trademarks in this
user’s manual

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IM 11M7A3-01E
 Precautions for Flameproof Instruments
1. General
Instruments with Flameproof construction (hereafter referred to as ameproof instruments) are
tested and certied by the public authority in accordance with the Labor Safety and Health Laws
of Japan.
A certied instrument is provided with a certication label and a nameplate that states
specications required for explosion protection performance. All installations of certied
instruments should be executed in compliance with the nameplate specications.
For details, see USERS' GUIDELINES for Electrical Installation for Explosive Gas Atmospheres
in General Industry, issued by the Research Institute of Industrial Safety of the Ministry of Labor
in Japan, 1994.
2. Flameproof Instruments
Instruments that can be termed "ameproof" must satisfy the following conditions.
They must have been tested and certied by an o󰀩cial body in accordance with the Industrial
Safety and Health Act and must carry a certication label on them.
They must be used in accordance with the specications stated on the nameplate.
The following operating conditions must be observed.
(1) ZS8D Detector
(a) Before opening the cover, remove power and allow the detector to stand at least 40
minutes.
(b) When the ambient temperature of the detector exceeds 30ºC, use wire resistant to
70ºC or greater for external wiring.
(c) The detector cannot be used except in mixed gases composing air or mixed gas with
oxygen concentration lower than air, or combustible gas or vapor.
(2) Converter
(a) Before opening the cover, remove power and make sure of non-hazardous
atmospheres. The warning added on page i must be observed.
(b) When the ambient temperature of the converter exceeds 50ºC, use wire resistant to
70ºC or greater for external wiring.
3. Flameproof Instrument Installation
(1) Installation Area
Flameproof instruments may be installed in hazardous areas where the specied gases are
present. They should not be installed in Division 0 areas.
Note: Hazardous areas are distinguished based on the frequency and duration of the occasions when explosive atmospheres are
encountered (IEC standard 79-10 classication of hazardous areas).
Areas where explosive atmospheres are continuously present or persist for long periods are classied as Division 0.
Areas where there is a risk that an explosive atmosphere will be encountered during normal operation of the equipment and
facilities are classied as Division 1.
Areas where there is no risk that an explosive atmosphere will be encountered during normal operation of the equipment and
facilities, and where an explosive atmosphere will persist for only a short period even if encountered, are classied as Division 2.
(2) Environmental Conditions
The standard environmental condition for ameproof instrument installation is an ambient
temperature range of −20 to 40°C. If the equipment is installed where there is a risk that it may be
exposed to radiant heat from plant equipment, direct sunlight, etc., take steps to heat-insulate the
equipment.

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IM 11M7A3-01E
4. External Wiring for Flameproof Instruments
External wiring for ameproof instruments must employ cable wiring. Securely ground all non-
live metal parts. For details, see USERS’ GUIDELINES for Electrical Installation for Explosive
Gas Atmospheres in General Industry, issued by the Research Institute of Industrial Safety of the
Ministry of Labor in Japan, 1994.
It is recommended to use cable glands for wiring.
• Use PVC insulated and sheathed control cable CVV (JIS C 3401) or equivalent. Where
protection from external physical damage is required, the cable must be enclosed in steel
conduit.
• Connections between such cables, or between such cables and wiring routed through
ameproof metal conduit, must be enclosed in a ameproof junction box per item (2), to
prevent any explosive gases from entering and ame fronts from moving in cables.
• For instruments in which cables are to be brought in through ameproof packings, use the
ameproof packing glands specied for use with the instruments and select the ameproof
packings whose internal diameters are appropriate for the cable external diameters.
• If a ameproof packing gland is used, screw it into the connection port so that a minimum
of ve threads are fully engaged, and fasten securely with a lock nut. It is mandatory that a
nonhardening sealant be applied to the threads for waterproong.
• The ameproof gland packing should be securely tightened to prevent the passage of
explosive gases or ame fronts.
5. Maintenance of Flameproof Instruments
When opening the cover for maintenance, the warning added on page i must be observed.
(1) Maintenance with Power ON
Maintenance of ameproof instruments with power on should be avoided unless there is no
alternative. However, if maintenance with power on cannot be avoided, a gas detector should
rst be used to verify that an explosive atmosphere is not present, before the instrument
cover is opened. If it is not possible to verify that explosive gases are not present, the scope of
maintenance should be limited to the following:
(a) Visual inspection
Visually inspect the ameproof instrument, metal conduit, cables, etc., for physical
damage and corrosion, and other mechanical and structural defects.
(b) Key operation
Adjustment should be made only to the extent that it can be done from the outside
without opening the instrument cover. Great care must be taken not to cause
mechanical sparks with tools.

<PREFACE> vii
IM 11M7A3-01E
(2) Repairs
If a ameproof instrument requires repair, turn o󰀨 the power, and carry the instrument to a
nonhazardous area. Observe the following points during repair:
(a) Make only such electrical and mechanical repairs as will restore the equipment to its
original condition. In the case of a Flameproof instrument, mechanical aspects such
as the gaps and path lengths of joints and mating surfaces, and mechanical strength
of enclosures, are critical factors in explosion protection. Exercise great care not to
damage the joints and mating surfaces, and to protect enclosures from shock.
(b) If damage is incurred by any area of a part critical to the maintenance of ameproof
performance (for example, threads, joints or mating surfaces, inspection windows,
connecting section between transmitter and terminal box, shrouds or clamps, external
wiring connection ports, etc.), contact Yokogawa.
Note: Never rethread a threaded connection or renish or touch up the nish on a joint or mating surface.
Doing so is extremely dangerous, as the ameproof explosion protection will be compromised.
(c) Unless otherwise specied, electrical circuits and mechanisms inside the enclosure
may be repaired by component replacement, as this will not directly a󰀨ect ameproof
explosion protection (however, the instrument should always be restored to its original
condition). Only Yokogawa-specied parts should be used for repair.
(d) Before returning a repaired instrument to service, always reinspect all parts necessary
for the preservation of ameproof explosion protection. Verify that all screws, bolts,
nuts, and threaded connections are properly tightened.
(3) Prohibition of Specication Changes and Modications
Users are prohibited from making any modications to specications or physical conguration,
such as adding or changing the conguration of external wiring ports.
6. Flameproof Packing Gland Selection
CAUTION
The ameproof packing glands used at the external wiring connection ports of Flameproof
instruments conforming to IEC standards are certied in combination with the ameproof
instruments. Therefore, only those ameproof packing glands specied by Yokogawa should be
used.

<PREFACE>
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IM 11M7A3-01E
After-Sales Warranty
nDo not modify the product.
nYokogawa warrants the product for the period stated in the pre-purchase
quotation. Yokogawa shall conduct dened warranty service based on its
standard. When the customer site is located outside of the service area, a fee
for dispatching the maintenance engineer will be charged to the customer.
nDuring the warranty period, for repair under warranty carry or send the
product to the local sales representative or service o󰀩ce. Yokogawa will
replace or repair any damaged parts and return the product to you.
• Before returning a product for repair under warranty, provide us with the model name
and serial number and a description of the problem. Any diagrams or data explaining the
problem would also be appreciated.
• If we replace the product with a new one, we won't provide you with a repair report.
nIn the following cases, customer will be charged repair fee regardless of
warranty period.
• Failure of components which are out of scope of warranty stated in instruction manual.
• Failure of components which are out of scope of warranty stated in instruction manual.
• Failure caused by usage of software, hardware or auxiliary equipment, which Yokogawa did
not supply.
• Failure due to improper or insu󰀩cient maintenance by user.
• Failure due to misoperation, misuse or modication which Yokogawa does not authorize.
• Failure due to power supply (voltage, frequency) being outside specications or abnormal.
• Failure caused by any usage out of scope of recommended usage.
• Any damage from re, earthquake, a storm and ood, lightning, disturbance, riot, warfare,
radiation, and other natural changes.
n Yokogawa does not warrant conformance with the specic application at the
user site. Yokogawa will not bear direct/indirect responsibility for damage due
to a specic application.
n Yokogawa will not bear responsibility when the user congures the product
into systems or resells the product.
n Maintenance service and supplying repair parts will be covered for ve years
after the production ends. For repair this product, please contact the nearest
sales o󰀩ce described in this instruction manual.

i
IM 11M7A3-01E
<CONTENTS>
Model ZS8
Flameproof
Zirconia Oxygen Analyzer
CONTENTS
IM 11M7A3-01E 6th Edition
tPREFACE........................................................................................................i
Introduction..................................................................................................iii

Precautions for Flameproof Instruments ............................................................ v
After-Sales Warranty.................................................................................viii
1. General ...................................................................................................... 1-1
1.1 System Conguration ...................................................................................... 1-1
1.2 Specications.................................................................................................... 1-6
1.2.1 General Specications ....................................................................... 1-6
1.2.2 Characteristics ................................................................................... 1-7
1.2.3 Flameproof Detector ZS8D ................................................................ 1-7
1.2.4 High Temperature Probe Adaptor ZS8P-H ...................................... 1-14
1.2.5 Flameproof Converter ZS8C ........................................................... 1-16
1.2.6 Options ............................................................................................. 1-20
2. Installation................................................................................................. 2-1
2.1 Installation of Flameproof General-purpose Detector.................................. 2-1
2.1.1 Installation Site ................................................................................... 2-1
2.1.2 Probe Insertion Hole .......................................................................... 2-1
2.1.3 Detector Installation ........................................................................... 2-2
2.1.4 Reference Air Outlet ........................................................................... 2-2
2.1.5 Heat Insulation ...................................................................................2-3
2.2 Installation of Flameproof High-temperature Detector ................................ 2-3
2.2.1 Installation Site ................................................................................... 2-3
2.2.2 Probe Insertion Hole .......................................................................... 2-3
2.2.3 Detector Installation ........................................................................... 2-4
2.2.4 Ejector Installation .............................................................................. 2-5
2.2.5 Heat Insulation ...................................................................................2-6
2.2.6 Blocking Radiant Heat ....................................................................... 2-6
2.3 Heat Insulation .................................................................................................. 2-6
2.3.1 Surface Temperature of Detector....................................................... 2-6
2.3.2
Portions Requiring Heat Insulation and Temperature to be Maintained 2-6
2.3.3 Methods to Change the Surface Temperature .................................. 2-7
2.3.4 Fitting a Thermal Insulating Jacket (Option) ...................................... 2-8
2.3.5 Heating and Insulation Range when Not Using a Heat-Insulating Jacket
2-15