WEC SENSOR INSTRUCTIONS

1.0

Introduction

The electrodeless conductivity sensors measure an induced current in a loop submerged in

solution. Two coils are enclosed within the sensor, which is immersed in the chemical whose
conductivity is of interest. An AC signal applied to one of the coils induces a current in the other
coil, which is directly proportional to the conductivity of the solution.
2.0

Specifications

2.1

Measurement Performance

2.2

Conductivity Ranges:
Conductivity Resolution:
Conductivity Accuracy:

01000 S/cm, 010,000 S/cm, 0100 mS/cm, 01000 mS/cm

1 S/cm, 1 S/cm, 0.1 mS/cm, 1 mS/cm
1% of Span

Temperature Range:

-5 to 80 C, 20 to 180 F (CPVC)
-5 to 120 C, 20 to 250 F (PEEK)

Temperature Resolution:
Temperature Accuracy:

1 (C or F)
1% of Reading

Mechanical

Part Number:

102730

190954

191145

Sensor Material:

PEEK

CPVC

PEEK

O-Ring Material:

EPR

FKM (in-line only)

N/A

Mounting Adapter Material:

316SS

CPVC (in-line only)

316 SS (in-line only)

Dimensions:

7" long x 1" diameter

7 long x 1.75 diameter

7 long x 1.75 diameter

Sensing Coil:

0.5" (1.3cm) aperture

0.5 (1.3cm) aperture

0.5 (1.3cm) aperture

Temperature Limitations:

+20 to 250F
(-5 to 120C)

+20 to 180F
(-5 to 80C)

+20 to 250F
(-5 to 120C)

Pressure Rating:

-15 to +250 psi

(-0.1 to 1.75 MPa)

-15 to +140 psi

(-0.1 to 0.98 MPa)

-15 to +250 psi

(-0.1 to 1.75 MPa)

3/4" NPTF thread

2" NPTM adapter

1 NPTM thread
2 NPTM adapter

1 NPTM thread
2 NPTM adapter

Mounting:
Submersion
In-Line

P/N 180122.H 2/13/04

3.0

Unpacking and Installation

3.1

Unpacking the unit

Inspect the contents of the carton. Please notify the carrier if there are any signs of damage
to the sensor or its parts. Contact your distributor if any of the parts are missing. The carton
should contain a 102730 PEEK, 191145 PEEK or 190954 CPVC sensor assembly and
instruction manual. Any options or accessories will be incorporated as ordered.

102730

190954

191145

Figure 1 Sensor Identification

3.2

Mechanical Installation
General Guidelines

Mount the sensor as close as possible to the controller.

Use only Walchem extension cable if 20 feet of cable is not sufficient.
Take care to shield the cable properly.
Maximum cable length is 120 feet.
Position the sensor such that a fresh, representative sample of the solution is available.
Position the sensor such that air bubbles will not be trapped within the sensing area.
Position the sensor where sediment or oil will not accumulate within the sensing area.
If cable is installed in metal conduit (recommended), either flexible conduit should be
used or some other provision made for removal of sensor from the process for
maintenance.

Notes:
1.
There are two grooves near the cable
end of the 102730 sensor. The groove
closest to the cable is NOT an O-ring
groove and should remain unoccupied.
The next groove, as shown in Figure 2,
IS for the O-ring.
2.

NOTCH FOR SENSOR

BORE ORIENTATION

NOT AN
O-RING GROOVE

BORE
OREINTATION
DIMPLE

O-RING FOR
PROCESS SEAL

Ensure that the sensor received has

the O-ring in the proper position.

Note: There are two notches at the cable cap

(shown in Figure 2) that line up with the flat
surfaces of the sensor doughnut. These
notches are an aid in positioning the sensor
in a pipe or vessel. The user should direct
the flow through the sensor bore.

BORE
SENSOR
DOUGHNUT

BORE

190954
or
191145
102730

Figure 2 Sensor Mounting

Submersion Installations
P/N 102730
The submersion sensor will be supplied from Walchem with a NPTF coupling, Walchem
p/n 190999. This coupling is designed to seal the cable from the process liquid by
compressing an O-ring on the sensor body. The NPTM thread on the sensor body is to
hold the coupling in place only; it will not seal. The adapter will slide over the cable and
over the threaded end of the sensor body, smooth bore first. A light coating of appropriate
grease on the O-ring will make it slide on a little easier. As the O-ring is compressed the
thread will engage. Now turn the adapter until the smooth bore end butts firmly against the
lip on the sensor.
Attach an appropriate length of user-supplied pipe to the NPTF coupling, using several
layers of PTFE tape on any threads. The sensor should be immersed away from the walls or
floor of the tank by a minimum of 2 inches. The support pipe must be long enough to be
above solution level. It should be sealed at the top, with a user supplied cable clamp, to
prevent moisture from filling the pipe. See figure 3B. This pipe will usually be suspended
from a bracket attached to the lip of the tank.
If the cable will be exposed to moisture (rain, hosing, etc.) it must be protected with
flexible conduit (preferably metal).

P/N 190954 or 191145

The submersion sensor requires a standard 1 NPTF coupling (user supplied) for
connection to standard compatible pipe. The sensor should be immersed away from the
walls and floor of the tank by a minimum of 2 inches. The support pipe must be long
enough to be above solution level. It should be sealed at the top, with a user supplied cable
clamp, to prevent moisture from filling the pipe. See Figure 3A. This pipe will usually be
suspended from a bracket attached to the lip of the tank.
If the cable run will be exposed to moisture (rain, hosing, etc.), it must be protected with
flexible conduit (preferably metal).
In-Line Installations
P/N 102730
Insert the sensor cable up through the custom bushing and lock nut as shown in figure 4B.
Lubricate the O-ring and press the sensor into the bushing. Secure the sensor in place using
the lock nut.
Thread the custom bushing into a 2 or larger diameter tee as shown in figure 4B. Note that
top of the sensor is notched to indicate the flat sides of the sensor. Use these notches to
align the bore of the sensor with the flow.
If the sensor will be exposed to moisture (rain, hosing, etc.) the cable end of the sensor
needs to be further protected. See the top section of Figure 4B for sealing the cable end.
P/N 190954
Thread the custom bushing into the end port of a 2 or larger diameter tee as shown in
Figure 4A. Note that the top of the sensor has a dimple drilled in the side to indicate the
direction of the flow channel. Align this dimple with the tee exit. 2 to adapters are
usually used on the entry and exit ports to allow the use of pipe.
Caution: It is important that the flow direction is in the end port and out the side port (as
shown in Figure 4A) to provide maximum cleaning of the sensor.
Insert the sensor cable up through the custom lock nut as shown in Figure 4A. Lubricate
the o-ring and insert the sensor into the custom bushing. The flange on the sensor provides
a sealing surface against the o-ring.
If the sensor will be exposed to moisture (rain, hosing, etc.) the cable end must be
protected.

3/4 NPT
STRAIN RELIEF
(USER SUPPLIED)

3/4 NPTF
TO 3/4 SOCKET
(USER SUPPLIED)

TEFLON TAPE
SEAL

3/8 X 3W POLYPRO MTG BRACKET

(USER SUPPLIED)

3/4 PIPE

1 NPTM TO
3/4 SOCKET
(USER SUPPLIED)

1" NPTF COUPLING

(USER SUPPLIED)

SENSOR,
WALCHEM P/N 190954 or
191145

Figure 3A Submersion Installation P/N 190954 or 191145

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3/4 NPT PVC

STRAIN RELIEF
(USER SUPPLIED)

3/4 NPTF CPVC

TO 3/4 SOCKET
(USER SUPPLIED)
TEFLON TAPE
SEAL

3/8 X 3W POLYPRO MTG BRACKET

(USER SUPPLIED)

3/4 CPVC PIPE

(USER SUPPLIED)
3/4 NPTM TO
3/4 SOCKET
(USER SUPPLIED)

O-RING SEAL ADAPTER 316 SS

WALCHEM P/N 190999

O-RING

SENSOR, PEEK
WALCHEM P/N 102730

Figure 3B Submersion Installation P/N 102730

3/4 NPT PVC

STRAIN RELIEF
(USER SUPPLIED)
3/4 NPTF CPVC
TO 3/4 SOCKET
(USER SUPPLIED)

3/4 PVC PIPE

(USER SUPPLIED)

TEFLON TAPE
SEAL
1 NPTF COUPLING
(USER SUPPLIED)
LOCK NUT, MOLDED
POLYPROPYLENE
WALCHEM P/N 102586

SENSOR, CPVC
WALCHEM P/N 190954

O-RING, FKM
WALCHEM P/N 102594
BUSHING, ADAPTER
2 CPVC
WALCHEM P/N 103212

2 NPT TEE
(USER SUPPLIED)

FLOW OUT

FLOW IN

Figure 4A In-Line Installation P/N 190954

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3/4 PVC PIPE

(USER SUPPLIED)

3/4 NPTF TO SOCKET

(USER SUPPLIED)
NUT, 3/4NPT, PVC
WALCHEM P/N 101478

TEFLON TAPE
SEAL

BUSHING, ADAPTER
2 316 SS
WALCHEM P/N 102925

O-RING

SENSOR, PEEK
WALCHEM P/N 102730

2 NPT TEE, (USER SUPPLIED)

Figure 4B In-Line Installation P/N 102730

3/4 NPT PVC

STRAIN RELIEF
(USER SUPPLIED)
3/4 NPTF CPVC
TO 3/4 SOCKET
(USER SUPPLIED)

3/4 PVC PIPE

(USER SUPPLIED)

TEFLON TAPE
SEAL
1 NPTF COUPLING
(USER SUPPLIED)

ADAPTER, 2"
316 SS
WALCHEM P/N
103217

SENSOR, PEEK
WALCHEM P/N 191145

2 NPT TEE
(USER SUPPLIED)

FLOW OUT

FLOW IN

Figure 4C In-Line Installation 191145

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Electrical Installation
Route the cable through one of the water tight cable glands on the WEC310 series
controller, and connect the wires according to the color code shown in figure 7. For cable
lengths beyond the standard 20 feet, a junction box (p/n 190851) and extension cable (p/n
190916-XX) must be used. The extension cable must be supplied by Walchem to ensure
reliability.
CABLE CLAMPS (2)

JUNCTION BOX
(WALCHEM P/N 190851)

EXTENSION
CABLE
ASSY
(OUTPUT)

COVER

SENSOR
CABLE
(INPUT)

BLK

BLK

WHT

WHT

DRN 1

DRN 1

RED

RED
BLACK

INPUT

SHIELD
BRN

GRN

OUTPUT

INPUT

190954 or 191145
SENSOR OR
EXTENSION
CABLE

102730
TERMINAL STRIP SENSOR
CABLE

OUTPUT

3.3

BLU

BLK

Figure 5 Junction Box Wiring

Mechanical mounting of the Junction Box

Open the junction box enclosure and use the two holes to screw the enclosure in place
(mounting screws are user supplied). See Figure 6 for dimensions. Place the junction box
within 20 feet of the sensor, in an area that is protected from excessive fumes or moisture.
Locate the cable entry on the bottom to minimize leakage problems.

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3.35

1.45

Figure 6 Junction Box Mounting Dimensions

Electrical installation of the Junction Box

Route the sensor cable through the water tight cable gland and attach the wires to the
terminal strip inside the junction box according to the color codes shown in figure 5.
Attach the extension cable to the WEC controller terminal strip according to the color
codes shown in figure 7.

4.0

Maintenance

4.1

Cleaning the sensor

Note: the controller must be recalibrated after cleaning the probe.
The probe should be cleaned periodically. The frequency required will vary by
installation. In a new installation, it is recommended that the probe be cleaned after
two weeks of service. To determine how often the probe must be cleaned, follow
the procedure below:
1. Read and record the conductivity.
2. Remove, clean and replace the conductivity probe.
3. Read conductivity and compare with the reading in step 1 above.
If the variance in readings is greater than 5%, increase the frequency of probe
cleaning. If there is less than 1% change in the reading, the probe was not dirty and
can be cleaned less often.

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FRONT PANEL

POWER SUPPLY

4-20mA

_ +

4-20mA
_ +

TB3

FLOW FLOW
METER METER
A
B

Cond/TempOptional
4-20 mA Board #2)

(Cond/Temp Optional
4-20 mA Board #1)

TB1

F1

F2

TB3

TB2
(Grounding
Stud)

NEU HOT

NEUTRAL

RELAY OUPUTS

SENSOR B

TB3

SENSOR A
P/N 102730
SENSOR

P/N 190954 or 191145

SENSOR OR
EXTENSION CABLE

TEMP+

BROWN

GREEN

TEMP GND

BLUE

BLACK

RCV+

RCV+

RED

RED

RCV GND

RCV GND

SHIELD

DRAIN 2

XMIT+

XMIT+

BLACK

BLACK

XMIT-

XMIT-

WHITE

WHITE

XMIT SHLD

XMIT SHLD

SHIELD

DRAIN 1

FLO SW B

FLO SW A

FLO SW GND

FLO SW GND

TEMP+
TEMP GND

TB1

Figure 7 Input Wiring

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Cleaning Procedure
An accumulation of dirt or debris on the sensor can effect the accuracy and the thermal
time constant. This accumulation should be removed periodically. This can be
accomplished by scrubbing with a toothbrush or stiff bottle brush. Soap or hand cleaner
may help. Harsh abrasives should be avoided. Rinse the sensor thoroughly before
returning to service.
Degaussing the sensor
Occasionally, when operating at low conductance (100-500 S), a sensor may become
magnetized. This might happen during maintenance or calibration, if the sensor is placed
near a large transformer or high magnetic field of a motor. Magnetization of the sensor
may result in erratic behavior or unexplained positive or negative offsets.
To degauss a sensor, use a degaussing tool such as that used for erasing magnetic tape
heads. With degaussing tool power on, bring the tool close to the sensor and move the tool
slowly around the sensor in close proximity. Then slowly move the tool away from the
sensor. Turn tool power off. This should be done with WEC310 power off.

5.0

Troubleshooting

To find out if the probe or the controller is faulty, select the Self-Test menu, as described in the
controller manual. If the problem is internal, an error message will appear on the lower line of the
display. Call Walchem customer service.
If the Self-Test passes proceed as described below.
To check the probe, check the probe electrical connections to the terminal strip (refer to
Figure 6). Make sure that the correct colors go to the correct terminals and the connections
are tight. Restore power and see if the conductivity is back to normal.
Test Resistor
Included with your controller is a resistor (4.32K) with flexible leads. This can be used
to test the controller and sensor. Select 1000S scale. With the probe in open air, loop the
wire through the sensor aperture and connect to the opposite end of the resistor. For a P/N
102730 sensor, the controller should stabilize at a reading of 500S on the 1000S scale.
However, this value may range from 250-1000S (the calibration has a range of 1/2X to
2X). For a P/N 190954 or 191145 sensor, the reading should be 800S, but may range
from 400-1600S.
The previous calibration will effect this reading. This is a quick operability test. It is not a
substitute for insitu calibration with a known liquid.
The last calibration performed will effect this reading. This is a quick operability test. It is
not a substitute for insitu calibration with a known liquid.
If the test resistor indicates that the sensor and controller are functional, your problem may
be caused by an accumulation of dirt. Try cleaning the probe (refer to section 4.2).
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Interference
The principle of operation involves a drive coil inducing a current in a receive coil. The
liquid being tested is the coupling media. Calibration factors are determined when the coils
are completely surrounded by this liquid. Should anything interfere with this coupling (i.e.
buildup on the sensor, bubbles on the sensor, close proximity to the tank wall, any
submerged object like a tumbling barrel), the reading will be distorted.
If the interference is a conductive object, it will increase the reading. If the interference is a
non-conductive object, (which displaces the liquid from the sensor). The reading will be
reduced. Keep these principles in mind when placing the sensor as well as when
troubleshooting.
Sensor Resistance Check
If the problem is suspected to be in the sensor, a high impedance meter can be used to
verify the readings shown in figure 8. Using a low impedance meter can cause the sensor
to become magnetized.

CONNECTION

RESISTANCE

1 TO 2

0 (SHORT)

1 OR 2 TO 3

INFINITE

1 OR 2 TO 4 OR 5

INFINITE

4 TO 5

0 (SHORT)

4 OR 5 TO 6 OR 7

INFINITE

6 TO 7

100K 1% @25C (77 F)

FLOWCELL

SEC

PVC JACKETED CABLE

PRI

P/N
102730

P/N 190954
or 191145

1
2
3

BLK
WHT
DRAIN 1

BLK
WHT
DRAIN 1

4
5

RED
DRAIN 2

RED
BLACK

6
7

BROWN
BLU

GREEN
BLK

RTD

Figure 8 Sensor Resistance Check

WALCHEM CORPORATION
5 BOYNTON ROAD HOPPING BROOK PARK HOLLISTON, MA 01746 USA
TEL: 508-429-1110
FAX: 508-429-7433
ON THE INTERNET: www.walchem.com

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