horiba TW-100 User manual

Water Distribution Monitor
TW-100
Instruction Manual
CODE:GZ0000080187H

January, 2018 © 2014 2018 HORIBA Advanced Techno Co., Ltd.
Preface
This manual describes the operation of the Water Distribution Monitor, TW-100.
Be sure to read this manual before using the product to ensure proper and safe operation of
the product. Also safely store the manual so it is readily available whenever necessary.
Product specifications and appearance, as well as the contents of this manual are subject to
change without notice.
Warranty and responsibility
HORIBA Advanced Techno Co., Ltd. warrants that the Product shall be free from defects in
material and workmanship and agrees to repair or replace free of charge, at option of HORIBA
Advanced Techno Co., Ltd., any malfunctioned or damaged Product attributable to
responsibility of HORIBA Advanced Techno Co., Ltd. for a period of one (1) year from the
delivery unless otherwise agreed with a written agreement. In any one of the following cases,
none of the warranties set forth herein shall be extended;
Any malfunction or damage attributable to improper operation
Any malfunction attributable to repair or modification by any person not authorized by
HORIBA Advanced Techno Co., Ltd.
Any malfunction or damage attributable to the use in an environment not specified in this
manual
Any malfunction or damage attributable to violation of the instructions in this manual or
operations in the manner not specified in this manual
Any malfunction or damage attributable to any cause or causes beyond the reasonable
control of HORIBA Advanced Techno Co., Ltd. such as natural disasters
Any deterioration in appearance attributable to corrosion, rust, and so on
Replacement of consumables
HORIBA Advanced Techno Co., Ltd. SHALL NOT BE LIABLE FOR ANY DAMAGES
RESULTING FROM ANY MALFUNCTIONS OF THE PRODUCT, ANY ERASURE OF DATA,
OR ANY OTHER USES OF THE PRODUCT.
Trademarks
Company names and brand names are either registered trademarks or trademarks of the
respective companies. (R), (TM) symbols may be omitted in this manual.

Regulations
FCC rules
Any changes or modifications not expressly approved by the party responsible for compliance
shall void the user's authority to operate the equipment.
Warning
This equipment has been tested and found to comply with the limits for a Class A digital
device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable
protection against harmful interference when the equipment is operated in a commercial
environment. This equipment generates, uses, and can radiate radio frequency energy and, if
not installed and used in accordance with the instruction manual, may cause harmful
interference to radio communications.
Operation of this equipment in a residential area is likely to cause harmful interference in
which case the user will be required to correct the interference at his own expense.
Korea certification


For Your Safety
Hazard classification and warning symbols
Warning messages are described in the following manner. Read the messages and follow the
instructions carefully.
Hazard classification
Warning symbols
This indicates an imminently hazardous situation which, if not avoided, will
result in death or serious injury. This is to be limited to the most extreme
situations.
This indicates a potentially hazardous situation which, if not avoided, could
result in death or serious injury.
This indicates a potentially hazardous situation which, if not avoided, may
result in minor or moderate injury. It may also be used to alert against
unsafe practices.
Without safety alert indication of hazardous situation which, if not avoided,
could result in property damage.
Description of what should be done, or what should be followed
Description of what should never be done, or what is prohibited

Safety precautions
This section provides precautions for using the product safely and correctly and to prevent
injury and damage. The terms of DANGER, WARNING, and CAUTION indicate the degree of
imminency and hazardous situation. Read the precautions carefully as it contains important
safety messages.
WARNING
ELECTRIC SHOCK
Opening the cover while powered on could result in electric shock.
Be sure to turn OFF power prior to opening the cover.
CAUTION
pH sensor is made of glass.
Be careful not to break the glass on the top of the sensor.
CHEMICAL CAUTION
Be careful not to drop color span calibration solution on your skin or drink it.
If color span calibration solution comes into contact with your skin or eyes, immediately wash away
with running water. If you swallow the solution, contact your doctor immediately.

Product Handling Information
Operational precautions
Use of the equipment in a manner not specified by the manufacturer may impair the protection
provided by the equipment. And it may also reduce equipment performance.
Exercise the following precautions:
Use the TW-100 in the temperature range shown in the general specifications.
Use the TW-100 in an environment free from corrosive gas.
Avoid using the TW-100 in a location close to equipment using strong electric power
(such as an electric furnace), or near a radio or sound wave source.
Do not give a shock or large vibrations to the TW-100. To move the TW-100 to another
location, contact our service or sales office.
Avoid turning ON the power again immediately after turning it OFF.
Do not operate touch panel with wet finger or solid tools, such as pen or driver.
Disposal of the product
When disposing of the product, follow the related laws and/or regulations of your country for
disposal of the product.

Manual Information
Description in this manual
Note
This interprets the necessary points for correct operation and notifies the important points for
handling the product.
Reference
This indicates the part where to refer for information.
Tip
This indicates reference information.

Contents
1 OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Part Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.1 Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.2 Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 PREPARATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 Opening the Inner Door of the Device . . . . . . . . . . . . . . . . . . . . . 7
2.2 Installing the pH Sensor (optional) . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Installing the Conductivity Sensor (optional) . . . . . . . . . . . . . . . . 9
2.4 Insert Beads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3 OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.1 Starting the Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2 Stopping the Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2.1 When stopping the device for a week or less . . . . . . . . . . . . . . . . . . 13
3.2.2 When stopping the device for a week or more . . . . . . . . . . . . . . . . . 14
3.3 Restarting the Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.3.1 When stopping the device for a week or less . . . . . . . . . . . . . . . . . . 15
3.3.2 When stopping the device for a week or more . . . . . . . . . . . . . . . . . 15
3.4 Maintenance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.5 Precautions for Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4 CALIBRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1 Calibration Patterns and Cycles . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.2 Precautions for Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.3 Displaying the Calibration Screen . . . . . . . . . . . . . . . . . . . . . . . . 23
4.4 Calibrating pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.4.1 pH 6.86 calibration and pH 9.18 calibration <pH> . . . . . . . . . . . . . . . 24
4.4.2 Adjustment calibration using sample water <pH> . . . . . . . . . . . . . . . 27
4.5 Calibrating Color . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.5.1 Common zero calibration and span calibration <color> . . . . . . . . . . 30
4.5.2 Individual zero calibration and span calibration <color> . . . . . . . . . . 35
4.5.3 Adjustment calibration using sample water <color> . . . . . . . . . . . . . 38
4.6 Turbidity Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

4.6.1 Common zero calibration and span calibration < turbidity > . . . . . . . 41
4.6.2 Individual zero calibration and span calibration <turbidity> . . . . . . . 45
4.6.3 Adjustment calibration using sample water <turbidity> . . . . . . . . . . . 48
4.7 Conductivity Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4.7.1 Span calibration <conductivity> . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4.7.2 Individual zero calibration <conductivity> . . . . . . . . . . . . . . . . . . . . . 54
4.7.3 Adjustment calibration using sample water <conductivity> . . . . . . . 57
4.8 Calibrating Residual Chlorine . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
4.8.1 Adjustment calibration using sample water <residual chlorine> . . . . 59
4.8.2 <Reference> Common zero calibration and span calibration
<residual chlorine> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
4.8.3 <Reference> Individual zero calibration and span calibration
<residual chlorine> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.9 Calibrating Water Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.9.1 Adjustment calibration using sample water <water pressure> . . . . . 68
4.10 Calibrating Water Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4.10.1 Adjustment calibration using sample water <water temperature> . . 70
5 FUNCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
5.1 Function List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
5.2 Input/Output Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
5.2.1 Setting EXT I/O IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
5.2.2 Setting external output during operation . . . . . . . . . . . . . . . . . . . . . . 75
5.2.3 Setting the analog output level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.2.4 Setting DISPLAYING MINUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.3 Automatic Zero Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
5.3.1 Setting ON/OFF of ZERO CAL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
5.3.2 Setting the calibration interval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
5.3.3 Setting the STANDARD TIME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
5.3.4 Setting ON/OFF of ZERO CAL. DRAIN . . . . . . . . . . . . . . . . . . . . . . 80
5.3.5 Setting the calibration time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
5.4 Auto Washing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
5.4.1 Turning auto washing ON and OFF . . . . . . . . . . . . . . . . . . . . . . . . . 83
5.4.2 Setting the WASHING INTERVAL . . . . . . . . . . . . . . . . . . . . . . . . . . 83
5.4.3 Setting the STANDARD TIME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.4.4 Setting the WIPING TIME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.5 Water Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
5.5.1 Setting the SAMPLING CHECK . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
5.5.2 Setting the SAMPLING TIME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
5.5.3 Perform the SAMPLING RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
5.6 Clock Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
5.7 LCD Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
5.7.1 Setting the BACK LIGHT TIME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

5.7.2 Controlling brightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
5.8 Touch Panel Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
5.9 Measurement Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
5.9.1 Setting the COEFFICIENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
5.9.2 Setting the range for turbidity and color . . . . . . . . . . . . . . . . . . . . . . . 94
5.9.3 Correcting color using turbidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
5.9.4 Setting the applied voltage for residual chlorine . . . . . . . . . . . . . . . . 96
5.10 Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
5.10.1 Performing ACTION operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
5.11 Checking the Device Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
5.11.1 Displaying the TEMPERATURE screen . . . . . . . . . . . . . . . . . . . . . . 99
5.11.2 Displaying the UNIT INFORMATION screen . . . . . . . . . . . . . . . . . . . 99
5.11.3 Setting ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
5.11.4 Analog input check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
5.11.5 Analog output check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
5.12 Data Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
5.12.1 Displaying the data history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
5.12.2 Deleting the data history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
5.12.3 Displaying a graph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
5.12.4 Calibration history check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
5.12.5 Deleting the calibration history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
5.12.6 Checking flow rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
5.12.7 Transferring data to a CF (Compact Flash) card . . . . . . . . . . . . . . . . 109
5.12.8 Initializing a CF (Compact Flash) card . . . . . . . . . . . . . . . . . . . . . . . 109
5.13 Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
5.13.1 Checking an alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
5.13.2 Canceling an alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
5.13.3 Checking the alarm history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
5.13.4 Deleting the alarm history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
5.13.5 Setting the ALARM TIME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
5.13.6 Setting the HIGH ALARM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
5.13.7 Setting the LOW ALARM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
5.13.8 Setting the UNIT HIGH ALARM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
5.13.9 Setting the UNIT LOW ALARM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
6 INPUT/OUTPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
6.1 Analog Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
6.2 Parallel Input/Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
6.2.1 Parallel output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
6.2.2 Parallel input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
6.3 Serial Input/Output (RS-232C) . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
6.4 Storing the Data on a CF (Compact Flash) Card . . . . . . . . . . . . . 123

7 MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
7.1 Maintenance Items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
7.2 Stopping and Restarting Operation . . . . . . . . . . . . . . . . . . . . . . . 128
7.3 Connection Locations for the Sensor Connectors . . . . . . . . . . . . 129
7.4 Parts Maintenance and Replacement . . . . . . . . . . . . . . . . . . . . . . 131
7.4.1 Replacing the mesh filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
7.4.2 Replacing the filter cartridge of the zero water filter . . . . . . . . . . . . . 132
7.4.3 Maintenance of the residual-chlorine sensor . . . . . . . . . . . . . . . . . . 133
7.4.4 Replacing and storing the conductivity sensor (optional unit) . . . . . . 135
7.4.5 Replacing and storing the pH sensor (optional) . . . . . . . . . . . . . . . . 136
7.5 Spare Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
8 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
8.1 Alarm List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
8.2 Alarm Causes and Corrective Actions . . . . . . . . . . . . . . . . . . . . . 142
9 REFERENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
9.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
9.2 Piping Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
9.3 Turbidity Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
9.4 Color Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
9.5 Residual Chlorine Measurement . . . . . . . . . . . . . . . . . . . . . . . . . 158
9.6 pH Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
9.7 Conductivity Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
9.8 Evaluating Coefficients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

1 OVERVIEW
1
1 OVERVIEW
1.1 Outline
This product is an automatic water-quality monitoring system that continuously measures
water quality at the ending of the feed pipe of the water supply.
The measurement items in the standard configuration are turbidity, color, residual chlorine and
water pressure. You can add pH, conductivity and water temperature as optional
measurement items by requesting them when ordering the product.
Note
You can not add the optional measurement items (pH, conductivity, water temperature) after delivery
of the product.
Features
Measurement data can be output through electrical analog outputs to a recorder, or
connected to a communication unit (optional) or output to a computer using the RS-232C
serial connection.
You can save and read measurement data using a compact flash memory card.
Measurement item Standard configuration Optional
Turbidity ○
Color ○
Residual chlorine ○
Water pressure ○
pH ○
Conductivity ○
Water temperature ○

1 OVERVIEW
2
1.2 Part Names
1.2.1 Device
Front
Front - With door open
Wiring inlet for
power connection
Operation indicator (green)
Lit when power is on
Wiring inlet for input/
output terminal
Alarm indicator (red)
Lights or blinks when
an alarm occurs
Locking handle
Calibration tank tray
Condensation
water outlet
Wiring inlet for
pressure sensor
Pressure-reduction valve
R1
Pressure sensor
PS1
Sample-water feed valve
SC1
CF (Compact Flash)
card insertion slot
Power switch
Display
Internal door
Door locking
screw
Flowmeter

1 OVERVIEW
3
Bottom - side connectors
Wiring inlet Air opening Condensation
water outlet
Drain
Calibration inlet Abnormal sample inlet
Sample inlet

1 OVERVIEW
4
1.2.2 Display
This section explains the contents of the display, using a typical screen as an example.
The screen is equipped with a touch panel. Do not operate touch panel with wet finger or
solid tools, such as pen or driver.
The measurement items pH, conductivity and water temperature are optional and not
included in the standard configuration.
If the touch panel is not operated for a certain amount of time, the backlight is turned to
OFF.
If not in the MEASUREMENT, DATA or ALARM screens, the display returns to the
measurement screen after about two hours of inactivity.
Screen example - Displaying the values of measured items
This screen displays the values for each measured item.
①②
③
④
⑤
⑥
⑦
No. Contents Examples
①Screen title MEASUREMENT, SPAN CAL..., DATA HISTORY
②Clock display 2004/01/30 09:57
③Measurement
item TURB., COL., CL.
④Measurement
value -
⑤Unit FTU, CU, mg/L, etc.
⑥Operation
buttons MAINTE., CAL., etc.
⑦System status
WARM UP!
The device is warming up
The device is always warmed up when the power is turned
on. The alarm display is cleared when the temperature of
the turbidity/color cell becomes stable.
Seq.
Action operation
The device is performing automatic calibration, automatic
cleaning and alarm check setting, or the operations are
finished and output is on hold .
MAINTENANCE
Maintenance mode
The device is in maintenance mode.
See "3.4 Maintenance Mode" (page 15).

1 OVERVIEW
5
Screen example- Menu items are displayed
Screen example- History and Information confirmation display
No. Contents Examples
①Screen title DATA, I/O SETTING, etc.
②Screen page
number 1/2, 2/2, etc.
③Menu item DATA HISTORY, GRAPH, etc.
④Next page 
①②
③
④
No. Contents Examples
①Screen title ALARM HISTORY, TEMPERATURE, etc.
②Contents
heading ALARM, etc.
③Data list 
②
③
①

2 PREPARATION
6
2 PREPARATION
The following preparations are required before operating the device. See Installation Manual
for installation, piping and wiring instructions.
Status of parts at delivery
pH sensor installation: For measuring pH (optional)
Conductivity sensor installation: For measuring conductivity (optional)
Beads insertion: For cleaning the residual-chlorine sensor
Parts Status on Delivery
Mesh filter Installation required
Zero water filter Installation required
Residual-chlorine
sensor Installed
Conductivity sensor Installation required
pH sensor Installation required
pH sensor Conductivity sensor
(Optional) (Optional)
Insert beads
Sample water feed valve
Mesh filter
must be closed.

2 PREPARATION
7
2.1 Opening the Inner Door of the Device
1. Push the bottom of the locking handle, and open the door while holding the handle.
2. Make sure that the sample water feed valve is closed and the power is OFF.
3. Turn and remove the door-locking screw and open the inner door.
4. Attach the fixing bracket to the inside of the door to hold the door in place.
To close the door, reverse the procedure.
Locking handle
Door-locking screw
Fixing bracket
Sample water feed valve
must be closed.

2 PREPARATION
8
2.2 Installing the pH Sensor (optional)
1. Make sure that the sample water feed valve is closed and the power is OFF.
2. Remove the protective cap, liquid-junction washer, rubber cap and connector cap
from the pH sensor.
3. Push the brown protrusion on the side of the sensor into the pH cell, as shown in
the following figure, and turn the sensor to the left.
Note
The pH sensor top is made of glass. Take care not to break it when pushing the sensor in.
Be careful not to loose the protective cap, liquid junction washer, rubber cap and connector cap
as they are used to store the sensor.
4. Connect the pH sensor to the connector.
Reference
"7.3 Connection Locations for the Sensor Connectors" (page 129)
Protective cap
Liquid-junction washer
Rubber cap
Connector cap
pH cell
pH sensor
Brown protrusion
Sample water feed valve
must be closed.