Xylem WTW FCML 412-M12 Series User manual

OPERATING MANUAL
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FCML 412 N(-S)
FCML 412-M12(-x)
pH-INDEPENDENT SENSOR FOR FREE CHLORINE
FCML 412 N FCML 412 N-S FCML 412-M12(-x)

FCML 412 N(-S), FCML 412-M12
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Copyright © 2024, Xylem Analytics Germany GmbH
Printed in Germany.

FCML 412 N(-S), FCML 412-M12 Contents
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Contents
1Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.1 Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Electrical connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
2.1 Safety information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.1 Safety information in the operating manual . . . . . 6
2.1.2 Safety signs on the product . . . . . . . . . . . . . . . . . 6
2.1.3 Further documents providing safety information . 6
2.2 Safe operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.1 Authorized use . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.2 Requirements for safe operation . . . . . . . . . . . . . 7
2.2.3 Unauthorized use . . . . . . . . . . . . . . . . . . . . . . . . 7
3Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
3.1 Scope of delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Filling the membrane cap with electrolyte solution . . . . . . 8
3.3 Electrical connection . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.4 Installation in the flow through vessel D-CL . . . . . . . . . . 10
3.5 Installation in the flow through vessel D 19 . . . . . . . . . . 11
4Measurement / Operation . . . . . . . . . . . . . . . . . . . . . . . .14
4.1 Run-in period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2 Check of the sensor / analysis . . . . . . . . . . . . . . . . . . . . 14
4.3 Chlorine measurement with the FCML 412 . . . . . . . . . . 14
5Maintenance, cleaning, storage . . . . . . . . . . . . . . . . . . . .15
5.1 Cleaning the measurement electrode / exchanging the
membrane cap and electrolyte . . . . . . . . . . . . . . . . . . . . 15
5.2 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.3 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.4 Maintenance equipment and replacement parts . . . . . . 17
6Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
7Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
7.1 Measuring characteristics . . . . . . . . . . . . . . . . . . . . . . . 19
7.2 Application characteristics . . . . . . . . . . . . . . . . . . . . . . . 19
7.3 General data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
7.4 Electrical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Overview FCML 412 N(-S), FCML 412-M12
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1 Overview
The FCML 412 chlorine sensors are membrane-covered, amperometric sen-
sors for the determination of free chlorine.
1.1 Structure
With its special design (potentiostatic three electrode system), the sensor
measures all the free chlorine present (sum of gaseous dissolved chlorine,
1 Connection
– FCML 412 N:
PG7 gland
– FCML 412 N-S:
Screw/plug-in coupling for
connection cable AK-CL
– FCML 412-M12:
Flange plug for adapter
ADA CL/IDS
2 Shaft
3 Auxiliary electrode
4 Electrode finger
5 O-ring 14 x 1.8
6 Reference electrode
7 Measuring electrode
8 Valve opening (behind hose ring)
9 Membrane cap
10Membrane holder
11Membrane disk
figure 1-1 Structure: Example FCML 412 N
M48
2
1
8
4
9
10
3
11
6
7
5

FCML 412 N(-S), FCML 412-M12 Overview
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hypochloric acid and hypochlorite) and the chlorine that is bonded to isocy-
anuric acid. The sensor has a strongly reduced pH dependence.
The sensor has integrated measuring electronics and delivers a measuring
signal that is already temperature compensated. It does not require a zero
point adjustment. The routine calibration is carried out through comparison
with the photometric DPD method according to DIN 38408.
1.2 Electrical connection
FCML 412 N The FCML 412 N sensor is connected with the measuring transmitter (e.g.
MULTILINE 1000) via a two wire connection.
The wires are used for the power supply of the measuring transmitter and for
the transmission of measurement signals (4 - 20 mA current signal).
FCML 412 N-S The FCML 412 N-S sensor has a four-pin socket for connection to the
measuring transmitter (e.g. CL 7010) via the AK-CL cable (see section
5.4 MAINTENANCE EQUIPMENT AND REPLACEMENT PARTS).
The power supply and transmission of the measured signal (0 to -1500 mV
voltage signal) are carried out separately via two lines each.
FCML 412-M12 The FCML 412-M12 sensor has an M12 flange plug for connection to the
adapter ADA CL/IDS (see section 5.4 MAINTENANCE EQUIPMENT AND
REPLACEMENT PARTS).
The adapter ADA CL/IDS connects the sensor to the MIQ/IDS module of the
IQ Sensor Net.
Power supply and transmission of the measuring signal are carried out via
the adapter ADA CL/IDS.
Except for the different electrical connection, all FCML 412 sen-
sors are identical.

Safety FCML 412 N(-S), FCML 412-M12
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2Safety
2.1 Safety information
2.1.1 Safety information in the operating manual
This operating manual provides important information on the safe operation
of the product. Read this operating manual thoroughly and make yourself
familiar with the product before putting it into operation or working with it. The
operating manual must be kept in the vicinity of the meter so you can always
find the information you need.
Important safety instructions are highlighted in this operating manual. They
are indicated by the warning symbol (triangle) in the left column. The signal
word (e.g. "CAUTION") indicates the level of danger:
NOTE
indicates a situation where goods might be damaged if the actions mentioned
are not taken.
2.1.2 Safety signs on the product
Note all labels, information signs and safety symbols on the product. A
warning symbol (triangle) without text refers to safety information in this oper-
ating manual.
2.1.3 Further documents providing safety information
The following documents provide additional information, which you should
observe for your safety when working with the measuring system:
Operating manuals of other components of the FCML 412 N(-S),
FCML 412-M12 system (power packs, controller, accessories)
Safety datasheets of calibration and maintenance equipment (e.g. clean-
ing solutions).
WARNING
indicates a possibly dangerous situation that can lead to seri-
ous (irreversible) injury or death if the safety instruction is not
followed.
CAUTION
indicates a possibly dangerous situation that can lead to slight
(reversible) injury if the safety instruction is not followed.

FCML 412 N(-S), FCML 412-M12 Safety
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2.2 Safe operation
2.2.1 Authorized use
The authorized use of the FCML 412 N(-S), FCML 412-M12 is the stationary
measurement of chlorine in drinking water, swimming pool water and process
water. Only the operation and running of the product according to the instruc-
tions and technical specifications given in this operating manual is authorized
(see chapter 7 TECHNICAL DATA). Any other use is considered unauthorized.
2.2.2 Requirements for safe operation
Note the following points for safe operation:
The product may only be operated according to the authorized use spec-
ified above.
The product may only be supplied with power by the energy sources men-
tioned in this operating manual.
The product may only be operated under the environmental conditions
mentioned in this operating manual.
The product may not be opened.
2.2.3 Unauthorized use
The product must not be put into operation if:
it is visibly damaged (e.g. after being transported)
it was stored under adverse conditions for a lengthy period of time (storing
conditions, see chapter 7 TECHNICAL DATA).

Commissioning FCML 412 N(-S), FCML 412-M12
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3 Commissioning
3.1 Scope of delivery
Sensor FCML 412 with membrane cap M48
– Sensor FCML 412 N
or
– Sensor FCML 412 N-S
or
– Sensor FCML 412-M12
Dropping bottle with 100 ml electrolyte solution ELY-FCML 412 N
Polishing strip
Operating manual
3.2 Filling the membrane cap with electrolyte solution
NOTE
Risk of damage for the sensor in the case of improper handling.
Do not touch the electrode finger with your fingers.
Do not apply pressure to the membrane disk.
Do not unscrew the membrane holder.
When it is delivered, the membrane cap is not filled with electrolyte and is
loosely screwed onto the shaft. In order to put the sensor into operation, fill
the membrane head as follows:
Filling the mem-
brane cap 1. Unscrew the membrane cap from the electrode shaft. Place the
membrane cap on a clean (non-absorbent) surface.

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2. Cut off the tip of the dropping bottle until the opening in the tip is vis-
ible, then fill the membrane cap completely with electrolyte solution
making sure it is bubble free.
3. Lift off the hose ring of the membrane cap, which closes the valve
opening, from the side so that the valve opening is exposed (see pic-
ture below).
Hold the sensor shaft in an upright position and place it on the filled
membrane cap. Some of the electrolyte solution will leak over the
upper edge of the membrane cap while doing this. Then screw the
electrode shaft into the membrane cap. For this, first turn the elec-
trode shaft anti-clockwise until the thread catches; then slowly screw
in the electrode shaft as far as it will go until no gap can be seen
between the sensor shaft and membrane cap.
1 Valve opening
2 Hose ring
NOTE
Overpressure in the membrane cap can destroy the membrane disk.
Therefore, make sure the valve opening is not inadvertently closed
by your fingers. Excess electrolyte solution must be able to escape
freely at any time. Screw slowly so that no back pressure can devel
-
op.
4. Using a blunt object, slide the hose ring over the valve opening and
insert it evenly in the groove.
5. Rinse off any electrolyte solution adhering on the outside.
1
2

Commissioning FCML 412 N(-S), FCML 412-M12
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3.3 Electrical connection
How to connect the FCML 412 N(-S) sensor to the measuring transmitter or
the MIQ/IDS module is described in the operating manual of the measuring
transmitter.
How to connect the sensor FCML 412-M12(-x) to the MIQ/IDS module is
explained in the operating manual of the module MIQ/IDS.
3.4 Installation in the flow through vessel D-CL
The flow-through vessel D-CL is optimized for the FCML 412 N(-S) chlorine
sensors.
Proceed as follows to install the sensor:
The position in the flow through vessel has a considerable effect
on the approach flow and, hence, the measuring function of the
sensor. Therefore carefully position the sensor as described
below.
1. Insert the black O-ring, then the PVC slide ring in the 1" installation
opening of the flow through vessel.
2. Push the coupling ring onto the sensor.
3. Insert the sensor with the coupling ring in the flow-through vessel.
4. Screw the sensor tight with the coupling ring.

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NOTE
When commissioning, always open the feed slowly. A strong shock pressure
can destroy the membrane.
3.5 Installation in the flow through vessel D 19
The flow-through vessel D19 is optimized for the FCML 412-M12 chlorine
sensor.
1 Top edge of the coupling ring
2 Above the middle of the inlet opening
3 Lower edge of the groove
4 Top edge of the sensor
5. Tighten the coupling ring by hand. Make sure the sensor is firmly
attached. Otherwise, it can be pressed out of the flow through vessel
by pressure.
225 mm
94 mm
50 mm
1
1 mm
2
3
4

Commissioning FCML 412 N(-S), FCML 412-M12
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The FCML 412-M12 has a marking on its shaft for optimum installation in the
flow-through vessel D19.
Proceed as follows to install the sensor:
The position in the flow through vessel has a considerable effect
on the approach flow and, hence, the measuring function of the
sensor. Therefore carefully position the sensor as described
below.
1. Connect the ADA CL/IDS adapter to the M12 flange plug and screw
it tight.
2. Push the coupling ring of the flow-through vessel loosely onto the
sensor.
3. Insert the sensor with the coupling ring in the flow-through vessel.
1 Marking on the FCML 412-M12
2 Top edge of the coupling ring
3 Drain opening
4 Inlet opening
2
1
4
3

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NOTE
When commissioning, always open the feed slowly. A strong shock pressure
can destroy the membrane.
4. Align the marking (1) on the sensor with the top edge (2) of the cou-
pling ring.
5. Tighten the coupling ring by hand.
6. Tighten the coupling ring approx. a quarter turn further with the M32
assembly wrench.
Make sure the sensor is firmly attached. Otherwise, it can be pressed
out of the flow through vessel by pressure.
The assembly wrench, size M32, is available as an accessory
(see section 5.4 MAINTENANCE EQUIPMENT AND REPLACEMENT
PARTS)..

Measurement / Operation FCML 412 N(-S), FCML 412-M12
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4 Measurement / Operation
4.1 Run-in period
Polarization Each time the sensor has been refilled it must be polarized. To do this,
immerse the connected and voltage-supplied sensor in a well-stirred chlorine
solution with at least 5 mg/l chlorine for an hour. Then put the sensor into use
(measuring position). The sensor can be calibrated after a stabilizing time of
approx. 20 minutes. After approx. one day, a post-calibration should be
performed.
The position in the flow through vessel has a considerable effect on the
approach flow and, hence, the measuring function of the sensor. Therefore
carefully position the sensor as described below.
4.2 Check of the sensor / analysis
Calibration with the
DPD-1 method
The chlorine sensor has a linear characteristic curve. Calibration of the chlo-
rine sensor is carried out as a single-point calibration. The calibration value
(nominal value) is usually determined photometrically. A common procedure
for this is the DPD method for free chlorine. The photometer and test sets for
this are described in the WTW catalog or on the Internet.
How to carry out the calibration is described in detail in the operating manual
of the measuring transmitter.
4.3 Chlorine measurement with the FCML 412
The FCML 412 chlorine sensor measures inorganic chlorine compounds
dissolved in water. The measured values determined with the photometer
according to the DPD-1 method (free chlorine) are directly comparable to the
values determined by the sensor.
The sensor filled with electrolyte must not become dry and has
to be permanently supplied with electrical voltage. Otherwise the
characteristics of the membrane cap, electrode finger and elec-
trolyte will be changed (sometimes irreparably). The sensor may
only be stored in an unfilled condition (see also section
5.3 STORAGE).

FCML 412 N(-S), FCML 412-M12 Maintenance, cleaning, storage
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5 Maintenance, cleaning, storage
5.1 Cleaning the measurement electrode / exchanging the mem-
brane cap and electrolyte
We recommend to disconnect the sensor from the measuring transmitter
before starting any maintenance work.
If calibration is not possible due to readings that are too low, the measure-
ment electrode has to be cleaned with the enclosed polishing strip. Proceed
as follows:
1. Using a blunt object, lift the hose ring out of the guiding groove and
push it to the side so that the valve opening is uncovered.
1 Valve opening
2 Hose ring
NOTE
Negative pressure in the membrane cap can destroy the membrane
disk. Therefore, make sure the valve opening is not inadvertently
closed by your fingers while unscrewing the membrane cap.
2. Unscrew the membrane cap from the sensor shaft and pour away the
electrolyte solution.
3. Rinse the electrode finger and membrane cap with clean water and
dab them dry with a clean paper towel.
4. Clean the measurement electrode with the polishing strip.
To do so, place the polishing strip on a paper towel and hold it by a
corner. Then hold the electrode finger vertically with the tip down and
run the tip over the polishing strip two or three times.
NOTE
The brown coating on the shell (reference electrode) of the electrode
finger must not be polished off. This would destroy the sensor!
1
2

Maintenance, cleaning, storage FCML 412 N(-S), FCML 412-M12
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5.2 Cleaning
Removing lime
deposits on the
membrane cap
Remove lime deposits on the membrane cap as follows:
5.3 Storage
NOTE
The sensor may only be stored in an unfilled condition.
Proceed as follows to store the sensor:
Recommissioning For recommissioning, clean the electrode tip with the polishing strip and use
a new membrane cap (see section 5.1). The membrane cap can be put into
10 % acetic acid for some hours to remove any lime deposits (see
section 5.2).
5. Fill the membrane cap with fresh electrolyte solution as described in
section 3.2, screw it on the sensor shaft and make the sensor ready
for measurement.
After exchanging the electrolyte solution and/or membrane cap
the sensor has to be repolarized (see section 4.1 RUN-IN
PERIOD).
If calibration is still not possible after cleaning the measurement
electrode, change the membrane cap.
1. Unscrew the membrane cap from the sensor shaft and pour away the
electrolyte solution (see section 5.1).
2. Put the membrane cap into 10 % acetic acid for several hours.
3. Then thoroughly rinse the membrane cap with clean water.
4. Fill the membrane cap with fresh electrolyte solution as described in
section 3.2, screw it on the sensor shaft and make the sensor ready
for measurement.
1. Unscrew the membrane cap from the sensor shaft and pour away the
electrolyte solution (see section 5.1).
2. Thoroughly rinse the membrane cap and electrode finger with clean
water and dry them dust free.
3. Loosely screw the dry membrane cap on the sensor shaft. The mem-
brane disk must not touch the electrode finger.

FCML 412 N(-S), FCML 412-M12 Maintenance, cleaning, storage
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5.4 Maintenance equipment and replacement parts
Description Model Order no.
Accessory kit for chlorine sensor
FCML 412, including:
– 1x membrane cap M48
– 100 ml electrolyte solution
ELY-FCML 412 N
– Polishing strip
ZBK-FCML 412 N 205 246
Adapter for connecting the sensor
FCML 412-M12 to an IDS interface
ADA CL/IDS 108 155
Flow-through vessel D 19
for chlorine sensor FCML 412-M12
D 19 401 991
Accessory for the flow-through vessel D 19
– 1x assembly wrench M32
R-SET P 904 030

Disposal FCML 412
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6 Disposal
Handle and dispose of all waste in compliance with local laws and regulations.
EU only: Correct disposal of this product — WEEE Directive on waste elec-
trical and electronic equipment
This marking on the product, accessories or literature indicates that the
product should not be disposed of with other waste at the end of its working
life.
To prevent possible harm to the environment or human health from uncon-
trolled waste disposal, please separate these items from other types of
waste and recycle them responsibly to promote the sustainable reuse of
material resources.
Waste from electrical and electronic equipment can be returned to the
producer or distributor.

FCML 412 N(-S), FCML 412-M12 Technical data
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7 Technical data
7.1 Measuring characteristics
Measuring principle Membrane-covered, amperometric sensor with potentiostatic three-electrode
system and integrated measuring electronics
Measuring range
Response time t90 (90 % of the final value display after) approx. 120 s
pH dependency Approx. 10 % slope loss per increasing pH unit
Temperature com-
pensation‐
Automatic, by means of integrated temperature sensor
Polarization time Approx. 2 hours on commissioning or after exchanging the electrolyte
Calibration proce-
dure
Single-point calibration, e.g. with photometric measurement according to the
DPD-1 method as a reference
7.2 Application characteristics
Temperature range 0 ... 45 °C (32 ... 113 °F)
The measurement medium must be free of ice crystals.
pH application
range
pH 4... 9
Max. admissible
overpressure
3,0•105 Pa (3.0 bar), pressureless operation in the flow-through vessel
Working life of the
membrane cap
Typically 1 year (depending on measuring medium)
Approach flow Flow rate in the flow through vessel: 15 ... 30 l/h
Typical application
range
Drinking water, swimming pool water and mains water in the flow through
vessel
FCML 412-M12-20 0.01 ... 20.00 mg/l Cl2
FCML 412-M12-2
FCML 412 N
0.01 ... 2.00 mg/l Cl2
FCML 412 N-S 0.01 ... 10.00 mg/l Cl2
(upper limit depends on the slope)

Technical data FCML 412 N(-S), FCML 412-M12
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7.3 General data
Dimensions
Membrane cap M48
Membrane type Microporous, hydrophilic membrane
Electrolyte ELY-FCML 412 N (from ZBK-FCML 412 N)
Material
200 mm 175 mm
25 mm 25 mm
FCML 412 N: FCML 412 N-S:
175 mm
25 mm
FCML 412-M12(-x):
37 mm
Shaft PVC
Membrane cap PVC
Membrane holder, auxiliary elec-
trode
Stainless steel
Working electrode Gold
Reference electrode Ag/AgCl
Hose ring Silicone
Cable screw joint Polyamide