Walchem WCT400 Series, WCT410 Series Instruction Manual

W

W A L C H E M

IWAKI America Inc.

CT400/410 Controllers

WCT400/410 Series

Cooling Tower Conductivity Controller

Instruction Manual

Five Boynton Road Hopping Brook Park Holliston, MA 01746 USA

TEL: [phone] FAX: [phone] WEB: www.walchem.com

Notice

© 2014 WALCHEM, Iwaki America Inc. (hereinafter “Walchem”)
5 Boynton Road, Holliston, MA 01746 USA
[phone]
All Rights Reserved
Printed in USA

Proprietary Material

The information and descriptions contained herein are the property of WALCHEM. Such information
and descriptions may not be copied or reproduced by any means, or disseminated or distributed without
the express prior written permission of WALCHEM, 5 Boynton Road, Holliston, MA 01746.

This document is for information purposes only and is subject to change without notice.

Statement of Limited Warranty

WALCHEM warrants equipment of its manufacture, and bearing its identification to be free from
defects in workmanship and material for a period of 24 months for electronics and 12 months for
mechanical parts and electrodes from date of delivery from the factory or authorized distributor under
normal use and service and otherwise when such equipment is used in accordance with instructions
furnished by WALCHEM and for the purposes disclosed in writing at the time of purchase, if any.
WALCHEM's liability under this warranty shall be limited to replacement or repair, F.O.B. Holliston,
MA U.S.A. of any defective equipment or part which, having been returned to WALCHEM,
transportation charges prepaid, has been inspected and determined by WALCHEM to be defective.
Replaceable elastomeric parts and glass components are expendable and are not covered by any
warranty.

THIS WARRANTY IS IN LIEU OF ANY OTHER WARRANTY, EITHER EXPRESS OR IMPLIED, AS
TO DESCRIPTION, QUALITY, MERCHANTABILITY, FITNESS FOR ANY PARTICULAR PURPOSE
OR USE, OR ANY OTHER MATTER.

180324. K
April 2014

TABLE OF CONTENTS

1.0 INTRODUCTION ........................................................................................................................ 1

2.0 SPECIFICATIONS ..................................................................................................................... 2

2.1 Measurement Performance .................................................................................................... 2

2.2 Electrical: Input/Output ........................................................................................................... 2

2.3 Mechanical ............................................................................................................................. 2

2.4 WCT Variables and their Limits .............................................................................................. 3

3.0 UNPACKING & INSTALLATION ................................................................................................ 4

3.1 Unpacking the unit ................................................................................................................. 4

3.2 Mounting the electronic enclosure ......................................................................................... 4

3.3 Installation .............................................................................................................................. 4

3.4 Icon Definitions ....................................................................................................................... 4

3.5 Electrical installation ............................................................................................................... 8

4.0 FUNCTION OVERVIEW .......................................................................................................... 12

4.1 Front Panel ........................................................................................................................... 12

4.2 Display ................................................................................................................................. 12

4.3 Keypad ................................................................................................................................. 13

4.4 Access Code ........................................................................................................................ 13

4.5 Startup .................................................................................................................................. 13

4.6 Shut Down ............................................................................................................................ 13

5.0 OPERATION ............................................................................................................................ 14

5.1 Main Menu ........................................................................................................................... 14

5.2 Conductivity Menu ................................................................................................................ 16

5.3 Temperature Menu ............................................................................................................... 18

5.4 Bleed Menu .......................................................................................................................... 19

5.5 Feed Menu ........................................................................................................................... 21

5.6 WM1 and WM2 Menus ......................................................................................................... 24

5.7 Bio1 and Bio2 Menus ........................................................................................................... 25

5.8 Time Menu ........................................................................................................................... 29

5.9 Conductivity Alarm Menu ..................................................................................................... 30

5.10 4-20mA Menu ....................................................................................................................... 31

5.11 Access Code Menu .............................................................................................................. 32

5.12 Datalog Menu ....................................................................................................................... 33

5.13 Config Menu ......................................................................................................................... 34

5.14 Upgrade Menu ..................................................................................................................... 35

6.0 MAINTENANCE ....................................................................................................................... 36

6.1 Electrode Cleaning ............................................................................................................... 36

6.2 Replacing the Fuses ............................................................................................................ 37

7.0 TROUBLESHOOTING ............................................................................................................. 37

7.1 Error Messages .................................................................................................................... 37

7.2 Conductivity Readout Does Not Change ............................................................................. 38

7.3 Procedure for Evaluation of Conductivity Electrode ............................................................. 39

8.0 SERVICE POLICY ................................................................................................................... 39

1.0 INTRODUCTION

The Walchem WCT400 Series controllers offer conductivity and watermeter-based control of cooling
tower water, control of corrosion/scale inhibitor feed, and with the WCT410 models, control of two
biocide pumps. The inhibitor pump may be selected to operate in one of the following modes:
Feed and Bleed
Feed and Bleed with Lockout
Feed as a percent of Bleed
Feed as a percent of Time
Feed based on a Water Contactor input
Feed based on a Paddlewheel water meter input

The WCT series cooling tower controllers are supplied with a temperature compensated carbon
electrode with a cell constant of 1.0. The controllers are microprocessor driven industrial type with
on/off control outputs. A timed sample mode may be selected, and on small towers can reduce
installation costs by eliminating the need for a sampling bypass line. An optional isolated 4-20 mA
output that is proportional to the conductivity reading is available for all models.

Any set point may be viewed without interrupting control. Each set point change will take effect as soon
as it is entered. An access code is available to protect set point parameters, while still allowing settings
to be viewed.

The model WCT410 biocide outputs are scheduled on a user selectable 1, 2, or 4 week cycle. Each
biocide output is independent and may be programmed for one add per day. (in 1, 2 or 4 week cycle) or
up to 10 times per day (in daily cycle). It is possible to add both chemicals in the same day, however, as
a safeguard they will not occur at the same time. Biocide outputs may use independent pre-bleeds and
lockout times. All outputs are interlocked with a flow switch input.

An alarm relay is provided with WCT410 models. It is triggered by:
Low Conductivity reading
High Conductivity reading
No Flow situation
Bleed Timeout
Sensor Error
Temp Error

Our unique USB feature provides the ability to upgrade the software in the controller to the latest
version.

An advanced USB capability option is available. The Config file feature allows you to save all the set
points from a controller onto a USB flash disk, and then import them into another controller, making the
programming of multiple controllers fast and easy. The data logging feature allows you to save the last
2 month’s readings and events to a USB flash disk.

1

2.0 SPECIFICATIONS

2.1 Measurement Performance

Conductivity Range 0 - 10,000 µS/cm (microSiemens/centimeter)

Conductivity Resolution 1 µS/cm

Conductivity Accuracy 10 - 10,000 µS/cm ±1% of reading

Temperature Range 32 - 158°F (0 - 70°C)

Temperature Resolution 0.1°C

Temperature Accuracy ± 1% of reading

2.2 Electrical: Input/Output

Input Power

Input Signals

Conductivity electrode 1.0 cell factor, 10K thermistor

Flow Meter (optional) Isolated, dry contact closure required (i.e. relay, ,reed switch)

Flow Switch (optional) Isolated, dry contact closure required (i.e. reed switch)

Outputs

Mechanical Relays Pre-powered on circuit board switching line voltage

4 - 20 mA (optional) Internally powered

Agency Approvals

Safety UL 61010-1:2012 3rd Ed.

CSA C22.2 No. 61010-1:2012 3rd Ed.
IEC 61010-1:2010 3rd Ed.
EN 61010-1:2010 3rd Ed.

EMC IEC 61326-1:2005
EN 61326-1:2006
Note: For EN61000-4-6, EN61000-4-3 the controller met performance criteria B.
*Class A equipment: Equipment suitable for use in establishments other than domestic, and those directly
connected to a low voltage (100-240 VAC) power supply network which supplies buildings used for
domestic purposes.

0 - 10 µS/cm ±20% of reading

100-240 VAC, 50/60 Hz, 8A
Fuse: 1.0 ampere, 5 x 20 mm

6 A (resistive), 1/8 HP
All relays are fused together as one group, total current for this
group must not exceed 6A

Fully isolated
600 Ohm max resistive load
Resolution .001% of span
Accuracy ± 1% of reading

2.3 Mechanical

Enclosure Material Polycarbonate

Operating Ambient Temp 32 – 122°F (0 – 50°C)

Storage Temperature -20 – 180°F (-29 – 80°C)

Graphite electrode pressure rating 150 psi

Stainless steel electrode pressure rating 150 psi

High pressure electrode & flow switch

manifold pressure rating

Flow switch manifold pressure rating 150 psi

Flow switch manifold connections ¾" NPTF

NEMA Rating NEMA 4X

Dimensions 8.5" x 6.5" x 5.5"

Display 2 x 16 character backlit liquid crystal

300 psi

2

2.4 WCT Variables and their Limits

Low Limit High Limit

Conductivity menu

Temperature Menu

Bleed Menu

Set Point 0 µS/cm 10,000 µS/cm
Dead Band 5 µS/cm 500 µS/cm
Bleed Limit Time (set in hours/minutes) 1 minute 8 hrs: 20 min (enabled)

Bleed Volume 1 (gallons or liters) 9,999 (gallons or liters)

Feed Menu

Feed Lockout Timer (Mode A) 1 second 99 min: 59 sec
Percent of Bleed (Mode B) 5 % 99 %
Feed Time Limit (Mode B) 1 minute 99 min: 59 sec
Percent of Time (Mode C) 0.1 % 99 %
Feed Cycle Time (Mode C) 10 minutes 59 min: 59 sec
Time per Contact (Mode D) 1 second 59 min: 59 sec
÷ Contacts by (Mode D) 1 contact 100 contacts
Time Limit (Mode D & E) 1 minute 99 min: 59 sec
Time/Vol (Mode E) 1 second 59 min: 59 sec
Vol to Initiate Feed (Mode E) 1 9,999

WM1 and WM2 Menus

Gallons per Contact 1 gal/contact 500 gal/contact
Liters per Contact 1 L/contact 500 L/contact
K Factor (Paddlewheel) 0.01 pulse/vol 9,999.99 pulses/vol

Biocide Menus (WCT410 only)

Pre-Bleed (0 disables pre-bleed) 1µS/cm 9.999 µS/cm
Lockout 0 minutes 9 hrs:59 min
Add Time
Daily Adds 0 minutes 144 minutes
All other modes 0 minutes 1440 minutes

4-20 mA Menu 4 & 20 mA Settings 0 µS/cm 10,000 µS/cm

Access Code Menu New Value 0 9999

Alarm Menu* High & Low (set to zero to disable) 1% 50%

Datalog Menu (Optional)

Config Menu (Optional)

Upgrade Menu

*Note: The Alarm relay is non-programmable. Refer to the Main Menu diagram on page 16 for the list of error
conditions that trigger the alarm relay.

PPM Conversion Factor 0.200 ppm/µS/cm 1.000 ppm/µS/cm

Interval Time (sampling) 5 minutes 24:00 hours

Duration Time (sampling) 1 minute 59 min: 59 sec

% Calibration Range -50 +50

Makeup Volume 1 (gallons or liters) 9,999 (gallons or liters)

No variables

0=unlimited (disabled)

No variables

No variables

No variables

3

3.0 UNPACKING & INSTALLATION

3.1 Unpacking the unit

Inspect the contents of the carton. Please notify the carrier immediately if there are any signs of damage
to the controller or its parts. Contact your distributor if any of the parts are missing. The carton should
contain: a WCT400 series controller and instruction manual. Any options or accessories will be
incorporated as ordered.

3.2 Mounting the electronic enclosure

The WCT series controller is supplied with mounting holes on the enclosure. It should be wall mounted
with the display at eye level, on a vibration-free surface, utilizing all four mounting holes for maximum
stability. Use M6 (1/4" diameter) fasteners that are appropriate for the substrate material of the wall.
The enclosure is NEMA 4X rated. The maximum operating ambient temperature is 122°F (50°C); this
should be considered if installation is in a high temperature location. The enclosure requires the
following clearances:
Top: 2" (50 mm)
Left: 8" (203 mm)
Right: 4" (102 mm)
Bottom: 7" (178 mm)

3.3 Installation

Once the WCT series controller is mounted, the metering pumps may be located at any distance from
the controller. The conductivity electrode should be placed as close to the controller as possible, to a
maximum distance of 250 ft. Less than 25 ft is recommended. The cable must be shielded from
background electrical noise.
Always route low voltage (sensor) signals with at least a 6” separation from AC voltage wiring.

Locate the electrode tee where an active sample of cooling tower water is available and where the
electrode can easily be removed for cleaning. It must be situated so that the tee is always full and the
electrode is never subjected to a drop in water level resulting in dryness. Refer to Figure 1 for typical
installation.

IMPORTANT: To avoid cracking the female pipe threads on the supplied plumbing parts, use no more
than 3 wraps of Teflon tape and thread in the pipe FINGER tight plus 1/2 turn! Do not use pipe dope to

seal the threads of the flow switch because the clear plastic will crack!

3.4 Icon Definitions

Symbol Publication Description

IEC 417, No.5019 Protective Conductor Terminal

IEC 417, No. 5007 On (Supply)
IEC 417, No. 5008 Off (Supply)

ISO 3864, No. B.3.6 Caution, risk of electric shock

ISO 3864, No. B.3.1 Caution

4

SOLENOID
VALVE

COOLING TOWER

WATER
METER

HEAT
EXCHANGER

METERING
PUMPS

FLOW SWITCH

10.0" (254 mm)

Cooling Tower Contr oller

Cooling Tower Controller

PREV NEXT

EXIT

ENTER

www.walchem.com

CIRCULATING
PUMP

FLOW

FLOW

PREV NEXT

EXIT

ENTER

www.walchem.com

ELECTRODE

SAMPLE VALVE

1/4” POLYPRO PANEL

Figure 1 Typical Installation

5

17" (432 mm)

(F)

Cooling Tower Controller

TYPICAL INSTALLATION

INTERMITTENT SAMPLING

TO

CONSTANT

110 VOLTS

PREV NEXT

ENTER

www.walchem.com

PE DISCHARGE

CHEMICAL

PUMP

EXIT

TUBING

CHEMICAL

TANK

TO ELECTRODE
TO SOLENOID

(A)

TO

SANITARY

SERVER

(A)

(D)

(B)

(F)

(C)

(E)

SPRA Y T OWE R

(A) Unions; installed for replacement of
solenoid, strainer or probe

(B) ½" solenoid
(C) ½" Y-strainer

SHUTOFF
VALVE

CITY WATER

MAKEUP

SPRAY
PUMP

(D) ¾" PVC threaded tee probe
(supplied with controller)

(E) ½" PVC bulkhead fitting

winter drain

Figure 1a Typical Installation

Intermittent Sampling

6

Cooling Tower Controller

PREV NEXT

ENTER

TYPICAL INSTALLATION

SUBMERSION ELECTRODE

EXIT

TO

110 VOLT AC

OUTLET

CHEMICAL

PUMP

CHEMICAL

TANK

www.walchem.com

XYZX

VALVE

TO

SANITARY

SERVER

(OPTION "A")

CIRCULATION

PUMP

(X) Unions; installed for replacement of
solenoid or strainer
(Y) ½" Y-strainer

(Z) ½"solenoid

PROBE

COOLING

TOWER

(OPTION "B")

OPEN
SUMP

XYZX

VALVE

TO

SANITARY

SERVER

NOTE: LOCA TION OF SOLENOID VALVE
USING OPTION "A" OR OPTION "B"
DEPENDS ON SYSTEM CONFIGURATION.

DETAIL OF

PROBE ASSEMBL Y

CLIP PROBE
ASSEMBLY TO
SUMP WALL FOR
EASY REMOVAL
FOR CLEANING

¾" PROBE
IN PVC TEE

TO

CONTROLLER

1" PVC
PIPE

1" NPTF PVC
COUPLING

INSTALL APPROXIMA TELY
HALF-WAY IN SUMP VO LU ME

AVOID INSTALLATION NEAR
PUMP SUCTION INLET

Figure 1b Typical Installation

Submersion Electrode

7

UG

O

3.5 Electrical installation

The various standard wiring options are shown in figure 2. Your WCT series controller will arrive from
the factory prewired or ready for hardwiring. Depending on your configuration of controller options,
you may be required to hardwire some or all of the input/output devices. Refer to figures 3 and 4 for
circuit board layout and wiring.

Note: when wiring the optional flow meter contactor input, the 4-20 mA output or a remote flow switch,
it is advisable to use stranded, twisted, shield pair wire between 22-26 AWG. Shield should be
terminated at the controller ground stud (see figures 3 and 4).

1. There are live circuits inside the controller even when the power switch on the front panel is in
the OFF position! The front panel must never be opened before power to the controller is
REMOVED!
If your controller is prewired, it is supplied with a 8 foot, 18 AWG power cord with USA
style plug. A tool (#1 Phillips driver) is required to open the front panel.

2. When mounting the controller, make sure there is clear access to the disconnecting device!

3. The electrical installation of the controller must be done by trained personnel only and
conform to all applicable National, State and Local codes!

CAUTION

4. Proper grounding of this product is required. Any attempt to bypass the grounding will
compromise the safety of persons and property.

5. Operating this product in a manner not specified by Walchem may impair the protection
provided by the equipment.

CONDUCTIVITY
ELECTRODE

FLOW SWITCH
(OPTIONAL)

Figure 2a WCT400 Conduit Wiring

POWER

BLEED

FEED

PL

SPARES

4-20mA
(OPTIONAL)

FLOW METER
(OPTIONAL)

CONDUCTIVITY
ELECTRODE

FLOW SWITCH
(OPTIONAL)

Figure 2b WCT410 Conduit Wiring

POWER

BLEED

FEED

BIO 1

PLUG

BI

ALARM

2

SPARES

4-20mA
(OPTIONAL)

8

FLOW METER
(OPTIONAL)

F1

FEED

L2L2

BLEED

N.C.

N.O. N.C. N.O.

FLOW SW 1

IN-IN+

Contact Closure:

Polarity not critical

FLOW MTR 1

IN-

IN+

FLOW MTR 2

IN+ IN-

Hall Effect

Flow Meter

L1 L2/N

GROUND
STUD

G

R

G

N

R

N

1

/

2

Y

0

E

V

L

2

4

0

V

COND

T-T+

W

G

R

H

E

I

T

E

E

N

BLKRED

+5V

SHIELD

B

B

L

R

N

2

4

0

V

F2

L1 L2/N

K

1

2

0

V

WHT 120V
BLU 240V

Reed Switch

Flow Meter

Polarity not Critical

Conductivity

Electrode

Figure 3 Inputs

9

Power Supply

(115 VAC or 230 VAC)

Chart
Recorder

GROUND

STUD

V
0
2

1

N

R

G

R

G

FEED

L2L2

L2/N

L1

V

0

4

2

L

E

Y

/

N

GRN 120V
GRN/YEL 240V

BLEED

N.C.

N.O. N.C. N.O.

BLEED

N.C.

N.O. N.C. N.O.

FEED

WHT 120V
BLU 240V

NOTE: When connecting a
motorized ball valve, the pre-wired
pigtail must be removed and the
valve requires two wires, one to
N.O. to open the valve and one to
N.C. to close the valve.

Bleed Solenoid/

Motorized Ball Valve

Figure 4a WCT400 Outputs

W

H

B

T

L

U

2

4

BLK 120V
BRN 240V

IF MOTORIZED

BALL VALVE

1

2

0

V

0

V

BLK 120
BRN 240V

PUMP

10