General information.....................................................................................................................................................................6
Use of hazard information..................................................................................................................................................................6
User interface..................................................................................................................................................................................9
Turn the instrument on.....................................................................................................................................................................10
Turn the keypad sound off (optional)...............................................................................................................................................11
Standard operation....................................................................................................................................................................11
Calibrate the turbidimeter with StablCal® Standards.......................................................................................................................11
Prepare the StablCal standards................................................................................................................................................11
Using Gelex secondary standards...................................................................................................................................................13
Optical system check................................................................................................................................................................16
Prepare a sample cell......................................................................................................................................................................16
Clean the sample cell...............................................................................................................................................................16
Indexing a single sample cell....................................................................................................................................................17
Prepare the sample..........................................................................................................................................................................21
Prepare a representative sample..............................................................................................................................................21
Remove air bubbles from the sample.......................................................................................................................................21
Apply a vacuum.................................................................................................................................................................21
Use an ultrasonic bath.......................................................................................................................................................21
Prevent condensation on a sample cell....................................................................................................................................22
Manual or automatic ranging....................................................................................................................................................25
Signal averaging on or off.........................................................................................................................................................25
Using the air purge system.......................................................................................................................................................25
Using a flow cell........................................................................................................................................................................26
Install a flow cell................................................................................................................................................................26
Clean a flow cell assembly................................................................................................................................................26
Using a manual flow cell....................................................................................................................................................27
Use a cell adapter.....................................................................................................................................................................27
Install a cell adapter...........................................................................................................................................................28
Remove a cell adapter.......................................................................................................................................................28
Connect to a printer or computer.....................................................................................................................................................28
Configure the printer output.............................................................................................................................................................28
Configure the RS232 connection.....................................................................................................................................................28
Calibrate the turbidimeter with formazin standards..........................................................................................................................29
Making 4000-NTU formazin stock solution...............................................................................................................................32
Calibrate the turbidimeter with user-selected formazin standards...................................................................................................32
Prepare formazin standards – user selected............................................................................................................................33
Change the calibration points...................................................................................................................................................33
Clean the instrument........................................................................................................................................................................33
Replace the LED light source..........................................................................................................................................................33
Replace a fuse.................................................................................................................................................................................33
Replacement parts and accessories...............................................................................................................................36
3
Table of Contents
4
Specifications
Specifications are subject to change without notice.
SpecificationDetails
Measurement methodNephelometric
RegulatoryMeets ISO 7027, DIN EN 27027, DIN 38404 and NFT
Light sourceLight-emitting diode (LED) at 860 ± 30 nm
±2% of reading plus 0.01 FNU/NTU from 0–
1000 FNU/NTU
(under reference conditions)
Signal averaging on: 14 seconds (when
10 measurements are used to calculate the average)
SpecificationDetails
Power requirement115–230 VAC, 50/60 Hz (automatic power selection)
28 W maximum
Pollution
degree/installation
category
Protection Class1
Operating conditionsTemperature: 0 to 40 °C (32 to 104 °F)
Storage conditions–40 to 60 °C (–40 to 140 °F), instrument only
InterfaceRS232C serial interface by way of DB9 subminiature
Air purgeDry nitrogen or instrument grade air (ANSI MC 11.1,
Sample cellsRound cells 95 x 25 mm (3.74 x 1 in.) borosilicate
Sample requirements25 mm sample cell: 20 mL minimum
EnclosureHigh-impact polycarbonate plastic
Dimensions30.5 x 40 x 15.6 cm (12.0 x 15.7 x 6.1 in.)
2; II
Relative humidity: 0–90% at 25 °C, 0–75% at 40 °C,
noncondensing
Altitude: 2000 m (6560 ft) maximum
Indoor use only
D-shell connector for data output to computer or
printer, and data input (command). No handshaking.
1975)
0.1 scfm at 69 kPa (10 psig); 138 kPa (20 psig)
maximum
Hose barb connection for 1/8-inch tubing
glass with rubber-lined screw caps
Note: Smaller sample cells (less than 25 mm) can be used
when a cell adapter is used.
0 to 95 °C (32 to 203 °F)
Note: Refer to Use a cell adapter on page 27 for the
minimum sample size when not using a 25 mm sample cell.
English 5
SpecificationDetails
Weight3.8 kg (8.5 lb)
CertificationCE, cETLus
1
Turbidity specifications identified using recently prepared formazin standard
and matched 1-inch sample cells.
2
Intermittent electromagnetic radiation of 3 volts/meter or greater may cause
slight accuracy shifts.
General information
In no event will the manufacturer be liable for direct, indirect, special,
incidental or consequential damages resulting from any defect or
omission in this manual. The manufacturer reserves the right to make
changes in this manual and the products it describes at any time, without
notice or obligation. Revised editions are found on the manufacturer’s
website.
Use of hazard information
D A N G E R
Indicates a potentially or imminently hazardous situation which, if not avoided, will
result in death or serious injury.
Indicates a potentially or imminently hazardous situation which, if not avoided,
could result in death or serious injury.
Indicates a potentially hazardous situation that may result in minor or moderate
injury.
Indicates a situation which, if not avoided, may cause damage to the instrument.
Information that requires special emphasis.
W A R N I N G
C A U T I O N
N O T I C E
Safety information
N O T I C E
The manufacturer is not responsible for any damages due to misapplication or
misuse of this product including, without limitation, direct, incidental and
consequential damages, and disclaims such damages to the full extent permitted
under applicable law. The user is solely responsible to identify critical application
risks and install appropriate mechanisms to protect processes during a possible
equipment malfunction.
Please read this entire manual before unpacking, setting up or operating
this equipment. Pay attention to all danger and caution statements.
Failure to do so could result in serious injury to the operator or damage
to the equipment.
Make sure that the protection provided by this equipment is not impaired.
Do not use or install this equipment in any manner other than that
specified in this manual.
6 English
Precautionary labels
Read all labels and tags attached to the instrument. Personal injury or
damage to the instrument could occur if not observed. A symbol, if noted
on the instrument, will be included with a danger or caution statement in
the manual.
This symbol, if noted on the instrument, references the instruction
manual for operation and/or safety information.
Electrical equipment marked with this symbol may not be disposed of
in European public disposal systems after 12 August of 2005. In
conformity with European local and national regulations (EU Directive
2002/96/EC), European electrical equipment users must now return
old or end-of-life equipment to the Producer for disposal at no charge
to the user.
Note: For return for recycling, please contact the equipment producer or supplier
for instructions on how to return end-of-life equipment, producer-supplied
electrical accessories, and all auxiliary items for proper disposal.
Certification
Canadian Radio Interference-Causing Equipment Regulation,
IECS-003, Class A:
Supporting test records reside with the manufacturer.
This Class A digital apparatus meets all requirements of the Canadian
Interference-Causing Equipment Regulations.
Cet appareil numèrique de la classe A respecte toutes les exigences du
Rëglement sur le matériel brouilleur du Canada.
FCC Part 15, Class "A" Limits
Supporting test records reside with the manufacturer. The device
complies with Part 15 of the FCC Rules. Operation is subject to the
following conditions:
1. The equipment may not cause harmful interference.
2. The equipment must accept any interference received, including
interference that may cause undesired operation.
Changes or modifications to this equipment not expressly approved by
the party responsible for compliance could void the user's authority to
operate the equipment. 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 their expense. The following
techniques can be used to reduce interference problems:
1. Disconnect the equipment from its power source to verify that it is or
is not the source of the interference.
2. If the equipment is connected to the same outlet as the device
experiencing interference, connect the equipment to a different
outlet.
3. Move the equipment away from the device receiving the interference.
4. Reposition the receiving antenna for the device receiving the
interference.
5. Try combinations of the above.
Product overview
The 2100N IS laboratory turbidimeter measures turbidity in FNU
(Formazin nephelometric units) and NTU (nephelometric turbidity units).
NTUs are calculated using the conversion factors of 1.0 NTU per
1.0 FNU.
The turbidimeter has an RS232 output for connection to a printer, data
logger or computer.
Figure 1 Front overview
1 Keypad4 Cover for the sample cell
compartment
2 Sample cell holder5 Five-digit LED display
3 Light shield
English 7
Figure 2 Back overview
1 Power cord connector4 DB9 connector for RS232 cable
2 Fuse holder5 Air purge fitting
3 Power switch
Product components
Refer to Figure 3 to make sure that all components have been received.
If any of these items are missing or damaged, contact the manufacturer
or a sales representative immediately.
Figure 3 Instrument components
1 2100N IS turbidimeter5 StablCal® Calibration kit
2 Oiling cloth6 Gelex® secondary turbidity
3 Six 1" sample cells (30 mL) with
caps
4 Silicone oil8 Power cord
1
Supplied with 4790000 only.
standardization kit
7 Dust cover
1
8 English
User interface
Figure 4 Keypad
1 ENTER key5 UNITS AVG key key
2 EDIT (arrow) keys6 SETUP key
3 RANGE key7 PRINT key
4 UNITS/Exit key8 CAL key
Table 1 Key descriptions
KeyDescription
Enters the value on the display. Starts the measurement of a
calibration standard. Clears data from the buffer.
Changes the numbers and/or letters on the display. Steps through
the calibration standards. The right arrow key moves the cursor to
the previous or next digit.
Table 1 Key descriptions (continued)
KeyDescription
Turns signal averaging on or off.
Turns on Setup mode and starts the selection of the setup number.
Sends the data that is on the display to a printer or computer.
Sends a calibration data report to a printer or computer when in
Calibration mode. Sends diagnostic results to a printer or computer
if held down when the instrument is turned on. Provides a print of
the setup commands when in Setup mode.
Starts or completes a calibration.
Selects automatic or manual ranging.
Selects the unit of measure. Exits Calibration or Setup mode
without saving changes.
English 9
Figure 5 Indicator lights
1 NTU light6 CAL? light
2 FNU light7 UNITS AVG light
3 Lamp light8 SETUP light
4 Manual Range light9 S0–S3 lights
5 Auto Range light
Table 2 Light descriptions
Light Description
NTUIlluminated when the instrument is set for NTU unit of measure.
FNUIlluminated when the instrument is set for FNU unit of measure.
Illuminated when the instrument light source is on.
Flashes when there is not sufficient light for measurement.
Table 2 Light descriptions (continued)
Light Description
Manual
Illuminated when the instrument is in manual ranging mode.
Range
Auto
Illuminated when the instrument is in auto ranging mode.
Range
CAL? Turns on during a calibration if the calibration data is not within the
acceptable range.
Flashes when the instrument should be calibrated.
Note: The CAL? light applies when a 25-mm sample cell is used. Ignore the CAL?
light if illuminated during calibration when a smaller sample cell is used. Push
UNITS/Exit to start measurements.
UNITS
Illuminated when signal averaging is on.
AVG
SETUP Illuminated when Setup mode is selected.
S0–S3 Show the current calibration point standard that is in use during
calibration.
Startup
Turn the instrument on
C A U T I O N
Infrared Light Hazard. The infrared light produced by this instrument can cause
eye injury. The infrared light source in this instrument only receives power when
the sample cell cover is closed.
1. Put the instrument on a stable, level surface that is free of vibration.
Do not put in direct sunlight.
2. Make sure that there is air circulation around the instrument. Keep
the back and area below the instrument free of material that could
decrease air flow through the vents.
3. Connect the power cord to the power plug on the back of the
instrument.
10
English
4. Connect the power cord to a power socket with ground contact.
5. Push the power switch on the back of the instrument to turn the
instrument on.
Turn the keypad sound off (optional)
By default, the instrument makes an audible sound when a key is
pushed. To turn the keypad sound off:
1. Push SETUP. The SETUP light turns on.
2. Use the arrow keys to select 00.
3. Push ENTER.
4. Use the arrow keys to select the sound option:
OptionDescription
BPAn audible sound is made when a key is pushed.
BP OFNo sound is made when a key is pushed.
5. Push ENTER.
6. Push SETUP.
Standard operation
Calibrate the turbidimeter with StablCal® Standards
Calibrate the turbidimeter before it is used for the first time using the
StablCal® sealed vial standards provided. As an alternative, calibration
can be done with recently prepared formazin standards. Refer to
Calibrate the turbidimeter with formazin standards on page 29.
Calibrate the turbidimeter at least every 3 months or as specified by the
regulating authority when data is used for ISO 7027 reporting.
Note: Unknown results may occur if standards other than the recommended
calibration points are used. The recommended calibration points (< 0.1, 20,
200 and 1000 NTU) provide the best calibration accuracy. Use of standards other
than StablCal, or user-prepared formazin, may result in less accurate calibrations.
The manufacturer cannot guarantee the performance of the instrument if calibrated
with co-polymer styrenedivinylbenzene beads or other suspensions.
Prepare the StablCal standards
When received and at intervals:
1. Clean the exterior surface of the StablCal vials with laboratory glass
cleaning detergent.
2. Rinse the vials with distilled or deionized water.
3. Dry the vials with a lint-free cloth.
Note: Never shake or invert the < 0.1 NTU standard. If the standard has been
mixed or shaken, do not move the vial for 15 minutes or more before using.
Note: Do not remove the caps from the sealed vials.
Make sure that the StablCal standards are at ambient instrument
temperature before use (and no greater than 40 °C (104 °F)).
Mix the standards before use:
1. Open the case lid. Remove the < 0.1 NTU standard from the plastic
case.
2. Leave the other standards in the case. Close the case lid.
3. Shake the case vigorously for at least 10 seconds.
4. Let the standards stand with no movement for 3–5 minutes before
use.
Calibration notes
• Make sure that the instrument is in the same ambient conditions as
where it is used.
• Make sure that the standards are at the same ambient temperature as
the instrument before use.
• Use only the provided silicone oil. This silicone oil has the same
refractive index as the vial glass and masks minor glass differences
and scratches.
• Store the oiling cloth in a plastic storage bag to keep the cloth clean.
• If power is lost during calibration, the new calibration data is lost and
the last calibration data is used. To exit a calibration and not save the
new values, push UNITS/Exit.
• In Calibration mode, automatic range and signal averaging on are
selected. When calibration is completed, all operational modes go
back to the last settings.
English
11
• All nephelometric (turbidity units of measure) calibrations are done at
the same time.
• The 4000-NTU standard does not have to be measured during
calibration if FNUs will be measured. Push CAL after the 1000 NTU
standard is measured to complete the calibration procedure.
StablCal calibration procedure
• The FNU values of StablCal standards and formazin standards are
calculated using the conversion factors of 1 FNU = 1 NTU.
1. Push CAL.
The S0 light turns on.
The NTU value of the
dilution water used in
the last calibration is
shown on the display.
12 English
2. Get the < 0.1 NTU
vial. Clean the vial with
a soft, lint-free cloth to
remove water spots and
fingerprints. Do not
invert the vial.
3. Apply a small bead
of silicone oil from the
top to the bottom of the
vial.
4. Use the oiling cloth
to apply the oil equally
to the surface of the
vial. Remove the
excess oil. Make sure
that the vial is almost
dry.
5. Put the vial in the
sample cell holder with
the triangle on the vial
aligned with the
reference mark on the
sample cell holder.
Close the cover.
6. Push ENTER.
The instrument display
counts down, then
measures the standard.
The next expected
standard (e.g., 20.00) is
shown. The S1 light
turns on.
7. Remove the vial
from the sample cell
holder.
8. Do steps 5–10 for
the other StablCal vials
(from lowest to highest
NTU standard).
The S0 light turns on
after the last vial is
measured.
9. Push CAL.
The instrument saves
the new calibration data
and goes back to
Measurement mode.
StablCal standards storage
• Do not move a StablCal standard to a different container for storage.
Keep StablCal standards in the plastic case provided with the cover
closed.
• Store at 5 to 25 °C (41 to 77 °F).
• For long-term storage (more than one month between use), keep at
5 °C (41 °F).
Using Gelex secondary standards
The Gelex secondary standards are used when a calibration check or an
optical system check is done. Refer to Calibration verification
on page 16 and Optical system check on page 16.
Gelex notes
• Measure the Gelex secondary standards on the instrument on which
they will be used. The measured values can only be used for one
instrument due to small differences in glass and instrument optical
systems.
• Do not keep a Gelex vial in the instrument for more time than is
necessary to complete measurement. The heat from the lamp can
change the turbidity value of a Gelex vial.
• Keep the Gelex standards at room temperature. Do not let Gelex
standards freeze or become warmer than 50 °C (122 °F). High
temperatures may cause Gelex suspensions to divide.
• Make sure that the Gelex standards are at ambient instrument
temperature before measurement.
English 13
Measure the Gelex stray light standard
Measure the Gelex stray light standard when the instrument is first received. Record the value on the Gelex vial with a permanent marker one time.
1. Clean the stray light
standard with a soft,
lint-free cloth to remove
water spots and
fingerprints.
7. Put the stray light
standard in the sample
cell holder with the
triangle on the vial
aligned with the
reference mark on the
sample cell holder.
Close the cover.
14 English
2. Apply a small bead
of silicone oil from the
top to the bottom of the
vial.
8. Read the value
when stable. Remove
the vial from the
instrument.
3. Use the oiling cloth
to apply the oil equally
to the surface of the
vial. Remove the
excess oil. Make sure
that the vial is almost
dry.
9. Record the value on
the white diamond
space on the vial using
a permanent marker.
4. Push RANGE to
select automatic
ranging.
The Auto Range light
turns on.
5. Push UNITS AVG to
turn signal averaging
off.
The UNITS AVG light
turns off.
6. Push UNITS/Exit to
select the NTU
measurement mode.
The NTU light turns on.
Measure the Gelex secondary turbidity standards
Measure the Gelex secondary turbidity standards each time the instrument is calibrated and record the new values on the Gelex vials with a water
soluble marker.
1. Clean the Gelex
vials with a soft, lint-free
cloth to remove water
spots and fingerprints.
7. Put the 0–2 NTU
Gelex vial in the sample
cell holder with the
triangle on the vial
aligned with the
reference mark on the
sample cell holder.
Close the cover.
2. Apply a small bead
of silicone oil from the
top to the bottom of the
vial.
8. Read the value
when stable. Remove
the vial from the
instrument.
3. Use the oiling cloth
to apply the oil equally
to the surface of the
vial. Remove the
excess oil. Make sure
that the vial is almost
dry.
9. Record the value on
the white diamond
space on the vial using
a water soluble marker.
Record on the vial if
Ratio was on or off
when the vial was
measured.
4. Push RANGE to
select automatic
ranging.
The Auto Range light
turns on.
10. Do steps 7–10 for
the other Gelex vials
(but not the stray light
standard). Measure
from lowest to highest
NTU.
5. Push UNITS AVG to
turn signal averaging
off.
The UNITS AVG light
turns off.
6. Push UNITS/Exit to
select the NTU
measurement mode.
The NTU light turns on.
English 15
Calibration verification
At intervals, measure the Gelex secondary turbidity standard that is
closest in value to the turbidity range to be measured. Do the steps in
Measure the Gelex secondary turbidity standards on page 15, but do not
change the value that is recorded on the vial.
If the measured value is within ±5% of the value recorded on the Gelex
vial, calibration is verified. If not, calibrate the instrument.
Note: The StablCal® primary turbidity standards can also be used to do a
calibration check. Prepare the StablCal vials before use. Refer to Prepare the
StablCal standards on page 11. Do not use the < 0.1 NTU StablCal vial as it does
not have an accurately identified NTU value. The instrument is calibrated if the
measured value is within ±5% of the StablCal value.
Optical system check
At intervals, measure the Gelex stray light standard to inspect the
integrity of the optical system. Do the steps in Measure the Gelex stray
light standard on page 14, but do not change the value that is recorded
on the vial.
If the value measured is similar to the value recorded on the Gelex stray
light standard (within ±0.02 NTU), the instrument works correctly. If not,
contact Customer Service.
Prepare a sample cell
Use a clean sample cell(s) for sample measurement.
Note: As an alternative, a flow cell can be used for sample measurement. Refer to
Using a flow cell on page 26.
Clean the sample cell
C A U T I O N
N O T I C E
Do not air dry the sample cells. Always store the sample cells with caps on to
prevent the cells from drying. For storage, fill the sample cell with distilled or
demineralized water.
1. Clean the internal and external surfaces of the sample cell and cap
with a laboratory glass cleaning detergent.
2. Fully rinse the sample cell many times with distilled or deionized
water.
3. Clean the internal and external surfaces of the sample cell and cap
with 1:1 hydrochloric acid.
4. Fully rinse the sample cell many times with distilled or deionized
water.
Note: If the sample cell will be used to measure low range turbidity samples or
dilution water, rinse with dilution water (not distilled or deionized water). Refer
to Prepare dilution water on page 20.
5. Dry the external surface of the sample cell with a soft, lint-free cloth.
6. Fill the sample cell with distilled or deionized water.
Note: If the sample cell will be used to measure low range turbidity samples or
dilution water, fill the sample cell with dilution water (not distilled or deionized
water).
7. Immediately put the cap on the sample cell.
Note: Hold the sample cell by the top only to minimize dirt and fingerprints.
16English
Chemical exposure hazard. Obey laboratory safety procedures and
wear all of the personal protective equipment appropriate to the
chemicals that are handled. Refer to the current material safety data
sheets (MSDS) for safety protocols.
Indexing a single sample cell
When measuring very low turbidity samples, use a single indexed sample cell or a flow cell for all measurements to get precise and repeatable
measurements. As an alternative, optically matched sample cells can be used. Refer to Matching sample cells on page 19. Matched sample cells do
not provide as good of accuracy and precision as a single indexed sample cell that is used for every measurement or a flow cell.
1. Rinse a clean,
empty sample cell two
times with dilution water
and drain to waste. Fill
the sample cell to the
line (about 30 mL) with
dilution water and
immediately put the cap
on the sample cell.
Refer to Prepare
dilution water
on page 20.
Let the sample cell sit
for at least five minutes
to degas.
2. Clean the sample
cell with a soft, lint-free
cloth to remove water
spots and fingerprints.
3. Apply a small bead
of silicone oil from the
top to the bottom of the
sample cell.
4. Use the oiling cloth
provided to apply the oil
equally to the surface of
the sample cell.
Remove the excess oil.
Make sure that the
sample cell is almost
dry.
5. Put the sample cell
in the sample cell
holder. Close the cover.
Record the value when
stable.
6. Remove the sample
cell, turn it about 1/8 of a
turn and put it in the
sample cell holder
again. Close the cover.
Record the value when
stable.
English 17
7. Repeat step 6 until
the lowest value is
shown on the display.
8. Put an orientation
mark on the marking
band near the top of the
sample cell where the
lowest value is shown.
18 English
Matching sample cells
To decrease the effects that optical differences among sample cells can have on turbidity measurements, measure samples in matched sample cells. It
may not be possible to match all sample cells due to the differences in glass.
1. Rinse two or more
clean, empty sample
cells two times with
dilution water and drain
to waste. Fill the
sample cells to the line
(about 30 mL) with
filtered dilution water
and immediately put the
cap on the sample cell.
Refer to Prepare
dilution water
on page 20.
Let the sample cell sit
for at least five minutes
to degas.
2. Clean the sample
cells with a soft, lint-free
cloth to remove water
spots and fingerprints.
Do not invert the
sample cell.
3. Apply a small bead
of silicone oil from the
top to the bottom of the
sample cells.
4. Use the oiling cloth
provided to apply the oil
equally to the surface of
the sample cells.
Remove the excess oil.
Make sure that the
sample cells are almost
dry.
5. Put the first sample
cell in the sample cell
holder. Close the cover.
Record the value when
stable.
6. Remove the sample
cell, turn it about 1/8 of a
turn and put it in the
sample cell holder
again. Close the cover.
Record the value when
stable.
English 19
7. Repeat step 6 until
the lowest value is
shown on the display.
13. Do steps 9–
12 again as necessary
to match the other
sample cells prepared
in steps 1–4.
8. Record the value.
Put an orientation mark
on the marking band
near the top of the
sample cell.
9. Put the second
sample cell in the
sample cell holder.
Close the cover.
Record the value when
stable.
10. Remove the
sample cell, turn it
about 1/8 of a turn and
put it in the sample cell
holder again. Close the
cover.
Record the value when
stable.
11. Repeat step
10 until the value
matches the first
sample cell value within
±0.005 FNU.
12. Put an orientation
mark on the marking
band near the top of the
sample cell where the
lowest value is shown.
Prepare dilution water
Dilution water is used when indexing a sample cell or matching sample
cells and to prepare formazin standards.
1. Collect at least 1000 mL of high-quality, low-turbidity water (i.e.,
distilled, demineralized or deionized water or filtered tap water).
20 English
2. Measure the turbidity of the water using the turbidimeter. Refer to
Turbidity measurement on page 23.
3. If the turbidity of the water is greater than 0.5 NTU, filter the water
using the sample filtration and degassing kit. Refer to the user
instructions provided with the sample filtration and degassing kit.
Prepare the sample
Proper sampling techniques are important to get accurate
measurements.
Prepare a representative sample
A representative sample accurately reflects the true condition of
the water source from which the sample was taken.
To prepare a representative sample:
• Gently but fully mix every sample before collecting aliquots (sample
portions). Mix by gentle inversion only. Do not shake.
• When collecting a sample from a water tap in a distribution system or
treatment plant, turn the water on for at least five minutes, then collect
the sample.
• When collecting a sample from a body of water (e.g., a stream or
storage tank), collect at least one liter (1 quart) and fully mix before
taking an aliquot for measurement. If the quality of the sample source
is not constant, collect samples at many locations at different depths
as necessary. Then, mix the samples together to prepare one sample
for measurement.
Remove air bubbles from the sample
If readings are not stable, air bubbles may be the cause. Remove air or
other gases from the sample before measurement even if no bubbles
can be seen.
The methods typically used for degassing are:
• Let the sample stand for several minutes
• Apply a vacuum
• Use an ultrasonic bath
• Apply heat
Let the samples stand for several minutes, then gently invert two or three
times before measurement.
In some cases, more than one method may be necessary to remove
bubbles (e.g., the use of heat with an ultrasonic bath may be necessary
in some severe conditions). Use care with these methods as sample
turbidity can be changed if these methods are not used correctly.
Apply a vacuum
Apply a vacuum with any available, clean, oil-free vacuum source, such
as the sample degassing kit, or an electric or hand-operated pump
equivalent to those in Accessories on page 36. The vacuum lowers the
atmospheric pressure above the sample letting trapped gas bubbles exit.
Vacuum works well with samples that are not viscous, such as water,
and do not contain volatile components. Application of vacuum to
viscous, volatile samples (i.e., paint resins) may cause volatile
components to come out of solution, and increase the bubbles.
Use an ultrasonic bath
An ultrasonic bath removes gas bubbles from most samples, especially
viscous liquids. The time necessary to remove bubbles may be a few
seconds to a minute or more.
To identify the time necessary for ultrasonic treatment:
1. Apply ultrasound to the sample for a short period of time, then
measure turbidity. Record the value and the treatment time.
2. Do step 1 again until there is no change in the turbidity of the
sample.
Note: In some instances, the use of ultrasound may divide gas bubbles and make
them more difficult to remove.
To use an ultrasonic bath:
1. Fill a clean sample cell with sample. Do not put the cap on the
sample cell.
2. Put 1/2 to 2/3 of the sample cell into the ultrasonic bath and let it stand
until visible bubbles are removed.
3. Remove the sample cell from the ultrasonic bath and put the cap on.
4. Fully dry the sample cell.
Apply heat
C A U T I O N
Make sure that the cap on the sample cell is loose. Increasing the temperature of
a tightly-capped sample cell may cause an explosion. More caution should be
taken when increasing the temperature of volatile compounds.
English21
If possible, do not use heat to accelerate degassing. Heat may change
the properties of the suspended particles and cause volatile components
to come out of the solution.
Gentle heat may be used to remove bubbles from very viscous samples
when used with vacuum or ultrasound. If applying heat to the sample is
necessary, do so only as much as is necessary to complete degassing.
Before measurement, decrease the temperature of the sample to the
initial temperature, then gently invert the sample.
Prevent condensation on a sample cell
Condensation may occur on the outside of the sample cell when
measuring a cold sample in a warm, humid environment. This
condensation or fogging of the sample cell interferes with turbidity
measurement.
To prevent condensation:
• Make sure that the outside of the sample cell is dry before
measurement.
• Use the air purge system as necessary. Refer to Using the air purge
system on page 25.
• If condensation occurs while using the air purge system, warm the
sample slightly. Let the sample sit at room temperature or partially put
the sample into a warm water bath for a short time. Gently invert the
sample cell before measurement.
Note: Warming may change the sample turbidity. Measure the sample without
warming when possible.
Measure over-range samples
The nephelometric method of turbidity measurement depends on light
scattering from suspended particles. If turbidity is very high, significant
amounts of light may be absorbed by the particles, and little light is
available for scattering. This results in a negative interference causing
the measured turbidity to be lower than the actual turbidity. This
condition is called “going blind”.
Methods used to prevent the instrument from going blind include:
• If measuring in the FNU mode, change the measurement units to NTU
by pushing UNITS/Exit. The NTU measurement mode (with Ratio on)
increases the measurement range.
• Sample dilution. Refer to Sample dilution on page 22.
When too much light is absorbed by the sample, the lamp icon on the
instrument display flashes.
Sample dilution
Use filtered sample, deionized water or distilled water for sample
dilution. Measure sample dilutions soon after they are prepared.
To prepare filtered sample, use the sample filtration and degassing kit.
Refer to the user instructions provided with the sample filtration and
degassing kit.
If the filters in the sample filtration and degassing kit plug quickly, use a
standard 47 mm filtration apparatus shown in Figure 6 with a membrane
filter or use a glass-fiber filter. Refer to Accessories on page 36.
After dilution and measurement, calculate the actual turbidity as follows:
1. Calculate the total volume:
Total volume = sample + dilution water
Example: 20 mL of sample and 80 mL of dilution water
Total volume = 20 mL + 80 mL = 100 mL
2. Calculate the dilution factor:
Dilution factor = total volume ÷ sample volume
Example: Dilution factor = 100 ÷ 20 = 5
3. Calculate the actual turbidity:
Actual turbidity = measured value × dilution factor
Example: Measured value = 2450 NTU
Actual turbidity = 2450 × 5 = 12,250 NTU
22
English
Figure 6 Prepare filtered sample using membrane or glass-fiber
filter
1 Filter pump4 Stopper7 Filter
2 Hose5 Filter holder
3 Filter flask6 Tweezers
Turbidity measurement
W A R N I N G
Potential explosion and fire hazard. This instrument is for measuring water based
samples. Do not measure solvent or combustible based samples.
For accurate turbidity readings use clean sample cells and remove air
bubbles. Refer to Clean the sample cell on page 16 and Remove air
bubbles from the sample on page 21.
Measurement notes
Proper measurement techniques are important in minimizing the effects
of instrument variation, stray light and air bubbles. For accurate and
repeatable measurements:
Instrument
• Make sure that the instrument is on a level, stationary surface that is
free of vibration during the measurement.
• Instrument stabilization is immediate. No warm-up time is necessary.
• Always close the sample compartment lid during measurement,
calibration and storage.
• Remove the sample cell from the instrument and turn off the
instrument if the instrument is stored for an extended time period
(more than a month).
• Keep the sample compartment lid closed to keep dust and dirt out.
Sample cells
• Always cap the sample cell to prevent spillage of the sample into the
instrument.
• Always use clean sample cells in good condition. Dirty, scratched or
damaged cells can result in readings that are not accurate.
• Make sure that cold samples do not “fog” the sample cell. Refer to
Prevent condensation on a sample cell on page 22.
• Store sample cells filled with distilled or deionized water and cap
tightly.
• For the best accuracy, use a single sample cell for every
measurement or a flow cell.
Note: As an alternative, matched sample cells may be used for measurements but
do not provide as good of accuracy or precision as a single indexed sample cell or
flow cell. When using matched sample cells, align the orientation mark on the
sample cell with the reference mark on the sample cell holder.
Measurement
• Measure samples immediately to prevent temperature changes and
settling. Before a measurement is taken, always make sure that the
sample is homogeneous throughout.
• Avoid sample dilution when possible.
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23
• Avoid instrument operation in direct sunlight.
Turbidity measurement procedure
1. Rinse a clean,
empty sample cell two
times with the solution
to be measured and
drain to waste. Fill to
the line (about 30 mL)
with sample and
immediately put the cap
on the sample cell.
7. Read and record the
value when stable.
Note: To send (via
RS232) a measurement
record, push PRINT.
24 English
2. Clean the sample
cells with a soft, lint-free
cloth to remove water
spots and fingerprints.
3. Apply a small bead
of silicone oil from the
top to the bottom of the
sample cells.
4. Use the oiling cloth
provided to apply the oil
equally to the surface of
the sample cells.
Remove the excess oil.
Make sure that the
sample cells are almost
dry.
5. Gently and slowly
invert the sample cell to
fully mix the sample. Be
careful not to add air
bubbles.
6. Put the sample cell
in the sample cell
holder with the triangle
on the sample cell
aligned with the
reference mark on the
sample cell holder.
Close the cover.
Measurement techniques
Measurements may be made with different operation mode settings and
optional accessories.
Calibrate the instrument whenever the sample cell pathlength is
changed.
Manual or automatic ranging
The manufacturer recommends that ranging be set to automatic for most
measurements.
The setting can be changed at any time during sample measurement.
Push RANGE repeatedly to step the instrument from automatic ranging
to manual ranging and then scroll through the manual range settings.
The Manual Range light turns on when manual ranging is selected. The
Auto Range light turns on when automatic ranging is selected.
Notes:
• When manual ranging is selected, the display flashes all 9s when the
sample being measured is greater than the selected range. The
display flashes all 0s when the sample measured is less than the
selected range.
• When automatic ranging is selected, the display flashes 9s when the
sample is greater than the maximum range of the instrument.Refer to
Measure over-range samples on page 22.
• When automatic ranging is selected, the display flashes all 0s when
the measurement is less than the range of the instrument or a
negative value. Calibrate the instrument.
Signal averaging on or off
Signal averaging corrects for reading fluctuations that are caused by
random drifting particles in the sample. When signal averaging is on, an
average reading is calculated every 3 seconds and shown on the
display.The last ten measurements are used to calculate the average
reading.
The manufacturer recommends that signal averaging be on for most
measurements.
Push UNITS AVG to turn signal averaging on or off. The UNITS AVG
light turns on when signal averaging is on.
Push ENTER when signal averaging is on to erase data in the signal
averaging buffer and provide an immediate update on the display as
necessary. This is especially useful when measuring samples with large
differences in turbidity.
Using the air purge system
The air purge system is used to keep condensation off the external
surface of the sample cell when cold samples are measured.
The air purge system pushes dry air through the optical compartment to
keep the outside the sample cell dry. The connection is made at the air
purge fitting on the back of the instrument Figure 2 on page 8.
Use dry nitrogen or instrument grade air (ANSI MC 11.1, 1975) at no
greater than 138 kPa (20 psig). The manufacturer recommends an air
consumption rate of 3 to 10 SCFH (standard cubic feet/hour).
When the sample temperature is about or less than 2 °C (35 °F), use a
desiccant dryer and particle filter to make sure that the dew point of the
air purge is less than the sample temperature. The air dryer contains
silica gel desiccant that turns pink. Replace the desiccant when it turns
pink.
If only shop air is available, use a coalescing filter with an automatic
drain and a dryer and particle filter to get instrument quality air. Use a
coalescing filter that typically operates for greater than 2000 hours.
Replace the particle filter when the air dryer is replaced.
Figure 7 and Figure 8 show the methods for connecting the two types of
air supply to the instrument.
Note: The dryer and filter are not necessary if dry nitrogen is used.
Figure 7 Instrument quality air
1 Particle filter (Balston DFU 9933-
05-BQ or equivalent)
2 Air dryer (Balston DAU 9933-
05-101 or equivalent)
3 Pressure regulator
4 Instrument air
English 25
Figure 8 Standard shop air
1 Particle filter5 Filter (Balston 100-12-BX or
2 Air dryer6 Auto drain (Balston 20-105 or
3 Coalescing filter/regulator (0–
30 psig)
4 Shop air
equivalent)
equivalent)
7 Filter housing (Balston
FR-920-30 or equivalent)
Using a flow cell
C A U T I O N
Do not use a flow cell with flammable samples or those that contain
hydrocarbons, solvents, concentrated acids or concentrated bases that may
damage wetted parts of the cells. Conduct tests before use of flow cells if sample
compatibility is not known.
Note: Do not use a high pressure flow cell kit with this instrument.
Use a flow cell to increase the speed, accuracy and reproducibility of
measurement. The manufacturer especially recommends using a flow
cell for low turbidity measurements.
Install a flow cell
1. Fully clean and assemble the flow cell, tubing and stand. Refer to
Clean a flow cell assembly on page 26 and the user instructions
provided with the flow cell.
2. Fill the flow cell and tubing with water and make sure that there are
no leaks or air bubbles.
Note: Air bubbles collect in areas that are not cleaned fully.
3. Clean the exterior surface of the flow cell with a soft, lint-free cloth to
remove water spots and fingerprints.
4. Apply a small bead of silicone oil from the top to the bottom of the
flow cell.
Note: Use only the provided silicone oil. This silicone oil has the same
refractive index as the flow cell glass and masks minor glass scratches.
5. Use the oiling cloth provided to apply the oil equally to the surface of
the flow cell. Remove the excess oil. Make sure that the flow cell is
almost dry.
Note: Put the oiling cloth in a plastic storage bag to keep the cloth clean.
6. Install the flow cell in the sample cell compartment.
7. Push the inlet and outlet tubes in the slots on the top of the
instrument enclosure so the sample cell cover can be installed. Refer
to the user instructions.
8. Put the flow-cell light cover over the flow cell.
Note: The standard sample cell cover of the instrument does not close when
the flow cell is installed.
Clean a flow cell assembly
1. Disassemble the flow cell assembly.
2. Clean the inside and outside of the glass parts with a laboratory
glass cleaning detergent. Follow with multiple rinses with distilled or
demineralized water.
Note: All tubing, flow cells, and caps in the flow cell assembly can also be
steam sterilized.
3. If measuring low turbidity samples, clean the inside and outside of
the glass parts with 1:1 hydrochloric acid and rinse multiple times
with dilution water.
4. Fill the sample cell with distilled or demineralized water and
immediately put the caps on the sample cell.
5. Clean the inside and outside of the plastic parts and tubing with
laboratory detergent and warm water.
Note: At intervals, replace the tubing as contaminants, including
microbiological growths, are difficult to remove from the inside surface of the
tubing.
26
English
6. Air dry the parts after cleaning.
Flow cell maintenance
• Keep all parts of the flow cell assembly clean.
• At intervals, replace all the tubing to make sure that the system is
clean. Keep the tubing as short as possible to minimize air locking and
lag time of sample flow. Locate the instrument as close to the drain as
possible.
Flow cell operation
• Do not use the flow cell for samples that contain large particles that
may collect and stop the sample from flowing.
• Slowly put the sample down the interior edge of the inlet reservoir to
prevent mixing of the sample, which can cause air bubbles. Air
bubbles create a false positive interference in a turbidity
measurement.
• If bubbles collect in the flow cell, gently tap the flow cell on a soft
surface to remove the bubbles. If bubbles continue to collect in the
flow cell, put the glass flow cell in liquid detergent for 24 hours and
then rinse fully.
• When measuring many samples of different turbidity, measure the
samples in order of the cleanest (lowest turbidity) to the dirtiest
(highest turbidity) to prevent contamination from one sample to the
next.
• Do not use greater than the recommended maximum sample pressure
of 34 kPa (5 psig).
• Keep the drain tubing below the center line of the instrument. If the
whole 152 cm (60 in.) length of drain tubing is used, make sure that
the end of the drain tubing is at least 46 cm (18 in.) below the center
line of the instrument.
• The flow-cell cover must be in place for the LED light source to
function.
Flow cell storage
• Install the reservoir cover when the system is not in use to prevent
contamination of the system by airborne particles.
• For short-term storage (a few hours), flush the system with distilled or
deionized water and leave the flow cell full of the flush water to
minimize air locks and build up of residue on the parts.
• For long-term storage, disassemble, fully clean and air dry all parts.
Using a manual flow cell
To set the flow rate, increase the height of the collection drain assembly
on the support rod to decrease the flow rate. Make sure that the bottom
of the collection drain assembly is no lower than 7.5 cm (3 in.) above the
support stand base.
To flush the flow cell, lower the collection drain assembly to the support
stand base to flush the flow cell.
Use a cell adapter
Many different test tubes, sample cells and ampules can be used to
measure samples when a cell adapter is used. Use a cell adapter when
the test tube, sample cell or ampule is less than 25 mm. Refer to
Accessories on page 36 for the available cell adapters.
Use only test tubes and sample cells that are free of significant
scratches. Clean and apply silicone oil to all sample cells, test tubes and
ampules used with the cell adapters. Refer to Clean the sample cell
on page 16.
Note: Performance specifications may be different than shown in Specifications
on page 5 when test tubes, sample cells or ampules less than 25 mm are used.
Use a cell adapter when:
• Only a small quantity of sample is available.
• The sample to be measured is in an ampule that cannot be opened.
Refer to Table 3 for minimum sample sizes.
Table 3 Minimum sample sizes
Test tube sizeSample
12 mm2.5 mL
13 mm3.5 mL
16 mm5 mL
19 mm7 mL
English 27
Install a cell adapter
1. Align the tab on the cell adapter toward the front of the instrument
(Figure 9).
2. Put the cell adapter in the sample cell holder.
3. Calibrate the instrument each time the sample cell diameter is
changed. Calibrate using sample cells of the same path length as the
sample cell that will be used to measure samples.
Note: If test tubes are taller than the cover for the sample cell compartment,
use the tall light shield provided with the cell adapter.
Figure 9 Install a cell adapter
Connect to a printer or computer
Use the serial interface (RS232) connector on the back of the instrument
to transmit data from the instrument to a printer or a serial
communication port on a computer. Refer to Figure 2 on page 8.
To connect a serial printer to the instrument, use a printer cable
assembly that is terminated with a standard 25-pin D connector. A serialto-parallel converter can be used to print to a parallel printer. Data is
transmitted to a printer as a 39-character string plus the line feed and
carriage return.
To connect a computer to the instrument, use a serial communication
cable with a DB9 connector.
Note: Use of the specified cable or equivalent is mandatory for CE compliance (a
shielded cable assembly must be used).
Configure the printer output
1. Push SETUP. The SETUP light turns on.
2. Select 01 using the arrow keys.
3. Push ENTER.
4. Use the arrow keys to change the value—SL Pr (slow print,
2.5 second delay) or FS Pr (fast print).
5. Push ENTER.
6. Push SETUP.
Configure the RS232 connection
Remove a cell adapter
1. Carefully pull the cell adapter up until it is half out of the sample cell
holder.
2. Slowly turn the cell adapter 90 degrees counter-clockwise.
3. Pull the cell adapter up to remove it.
N O T I C E
Do not force the cell adapter out of the instrument as serious damage can
occur.
28 English
1. Push SETUP. The SETUP light turns on.
2. Use the arrow keys to select an option:
OptionDescription
10Sets the baud rate (default=1200).
11Sets the character length (default=8).
12Sets the stop bit (default=1).
13Sets the parity select (default=NONE).
3. Push ENTER.
4. Use the arrow keys to change the value.
5. Push ENTER.
6. Push SETUP.
Computer (RS232) commands
A communication program (i.e., such as Window Terminal or ProComm
Plus) is recommended for computer operation of the instrument.
Configure the communication program to the RS232 connection settings.
Refer to Configure the RS232 connection on page 28.
Table 4 shows the RS232 command set for the instrument.
Table 4 RS232 command set
Command Description
VALGets the current measurement with the measurement units.
LSTGets the calibration standards and coefficients.
DATGets the current date.
To change the date, enter DAT=MM/DD/YY (MM=month, DD=day,
YY=year), then push Enter.
TIMGets the current time in 24-hour format.
To change the time, enter TIM=HH:MM (HH=hour, MM=minutes),
then push Enter.
RMNGets the recorder minimum value.
To change the recorder minimum value, enter RMN=XXXXX
(XXXXX=a number, minimum value=0), then push Enter.
RMXGets the recorder maximum value.
To change the recorder maximum value, enter RMX=XXXXX
(XXXXX=a number, maximum value=10,000), then push Enter.
RTNGets the recorder trim minimum value.
To change the recorder minimum value, enter RTN=XXXXX
(XXXXX=a number, minimum value=200), then push Enter.
Table 4 RS232 command set (continued)
Command Description
RTXGets the recorder trim maximum value.
To change the recorder maximum value, enter RTX=XXXX
(XXXX=a number, maximum value=4800), then push Enter.
SAVGets the signal average buffer size.
To change the signal average buffer size, enter SAV=XX (XX=a
number, maximum value=15, default=10), then push Enter.
Advanced operation
Calibrate the turbidimeter with formazin standards
The instrument may be calibrated using prepared formazin standards
made from 4000-NTU formazin stock solution. Refer to Accessories
on page 36.
Note: Use recently prepared formazin standards to get the accuracy specifications
for turbidity in Specifications on page 5.
Prepare formazin standards
For the best accuracy and long-term data comparability, use formazin
stock solution from Hach to make formazin standards.
Note: As an alternative, a 4000-NTU formazin stock solution that is prepared by
the user may be used to make formazin standards. Refer to Making 4000-NTU
formazin stock solution on page 32.
Prepare formazin standards immediately before calibration in an
environment that is at the same ambient temperature as the instrument.
Discard after use.
Refer to Table 5 for the procedures to make the recommended
calibration standards.
English
29
Table 5 Formazin standard preparation
Standard Step 1 Step 2 Step 3
20 NTUAdd 100 mL of
200 NTUAdd 50 mL of dilution
1000 NTU Add 50 mL of dilution
dilution water to a
clean 200-mL Class
A volumetric flask.
Refer to Prepare
dilution water
on page 20.
water to a clean 100mL class A
volumetric flask.
water to a clean 100mL class A
volumetric flask.
With a TenSette
Pipet, add 1.00 mL of
well-mixed 4000-NTU
formazin stock
solution to the 200mL flask.
With a TenSette
Pipet, add 5.00 mL of
well-mixed 4000-NTU
formazin stock
solution to the 100mL flask.
With a TenSette
Pipet, add 25.00 mL
of well-mixed 4000NTU formazin stock
solution to the 100mL flask.
®
1
1
Dilute to the mark
with dilution water.
Stopper and mix.
Dilute to the mark
with dilution water.
Stopper and mix.
Dilute to the mark
with dilution water.
Stopper and mix.
1
A class A volumetric pipet may be used in place of a TenSette Pipet.
Calibration notes
• Make sure that the instrument is in the same ambient conditions as
where it is used.
• Make sure that the standards are at the same ambient temperature as
the instrument before use.
• Use only the provided silicone oil. This silicone oil has the same
refractive index as the vial glass and masks minor glass differences
and scratches.
• Store the oiling cloth in a plastic storage bag to keep the cloth clean.
• If power is lost during calibration, the new calibration data is lost and
the last calibration data is used. To exit a calibration and not save the
new values, push UNITS/Exit.
• In Calibration mode, automatic range and signal averaging on are
selected. When calibration is completed, all operational modes go
back to the last settings.
• All nephelometric (turbidity units of measure) calibrations are done at
the same time.
• The 4000-NTU standard does not have to be measured during
calibration if FNUs will be measured. Push CAL after the 1000 NTU
standard is measured to complete the calibration procedure.
• The FNU values of StablCal standards and formazin standards are
calculated using the conversion factors of 1 FNU = 1 NTU.
30 English
Formazin calibration procedure
For the best accuracy, use four matched sample cells or the same sample cell for all measurements during calibration. Refer to Matching sample cells
on page 19.
1. Push CAL.
The S0 light turns on.
The NTU value of the
dilution water used in
the last calibration is
shown.
2. Rinse a clean
sample cell two times
with dilution water. Fill
the sample cell to the
line (about 30 mL) with
dilution water and
immediately put the cap
on the sample cell. Use
the same dilution water
that was used to
prepare the formazin
standards.
3. Clean the sample
cell with a soft, lint-free
cloth to remove water
spots and fingerprints.
Do not invert the
sample cell.
4. Apply a small bead
of silicone oil from the
top to the bottom of the
sample cell.
5. Use the oiling cloth
provided to apply the oil
equally to the surface of
the sample cell.
Remove the excess oil.
Make sure that the
sample cell is almost
dry.
6. Put the sample cell
in the sample cell
holder with the triangle
on the sample cell
aligned with the
reference mark on the
sample cell holder.
Close the cover.
English 31
7. Push ENTER.
The instrument display
counts down from 60 to
0, and then measures
the standard.
The instrument shows
the next expected
standard (e.g., 20.00).
The S1 light turns on.
8. Remove the sample
cell from the sample
cell holder.
9. Do steps 5–11 for
the other formazin
standards (from lowest
to highest NTU
standard). Mix each
formazin standard well
and rinse the sample
cell two times with
formazin standard
before the sample cell
is filled.
The S0 light turns on
after the last sample
cell is measured.
10. Push CAL.
The instrument saves
the new calibration data
and goes back to
Measurement mode.
Making 4000-NTU formazin stock solution
W A R N I N G
Chemical exposure hazard. Obey laboratory safety procedures and wear all of
the personal protective equipment appropriate to the chemicals that are handled.
Refer to the current material safety data sheets (MSDS) for safety protocols.
Note: Making formazin stock solution from raw materials is not recommended.
Preparation of formazin stock solution is temperature and technique sensitive. Use
Hach formazin stock solution to get the best instrument performance and analytical
standard accuracy.
1. Dissolve 5.000 grams of reagent grade hydrazine sulfate ((NH2)2–
H4H2SO4) in about 400 mL of demineralized water.
2. Dissolve 50.000 grams of reagent grade hexamethylenetetramine in
about 400 mL of demineralized water.
32 English
3. Quantitatively, put the two solutions in a 1-liter volumetric flask, and
dilute to volume with demineralized water. Mix fully.
4. Let the solution stand for 48 hours at 25 ± 1 °C (77 ± 1 °F).
Calibrate the turbidimeter with user-selected formazin
standards
The instrument may be calibrated using user-selected values of formazin
standards.
Calibration with user-selected values of formazin standards is done
using the same method that is used to calibrate the instrument with
recommended formazin standards with two differences:
• The prepared formazin standards used are user-selected standards
and not the recommended standards. Refer to Prepare formazin
standards – user selected on page 33.
• The calibration points that are shown on the display must be changed
as they occur so they agree with the turbidity of the user-defined
standards. Refer to Change the calibration points on page 33.
Note: Unknown performance may occur if standards other than the recommended
calibration points are used. The recommended calibration points (< 0.1, 20,
200 and 1000 NTU) provide the best calibration accuracy. Refer to Application note
128, Calibration Methods for Low-Level Turbidity Measurement.
Prepare formazin standards – user selected
User-selected values of formazin standards are prepared using the
same method that is used to prepare the recommended formazin
standards. Refer to Prepare formazin standards on page 29.
Prepare user-selected values of formazin standards to span the entire
range of the instrument. Four standards are necessary. Suggested
standards are in the range of:
• 10–30 NTU
• 180–220 NTU
• 900–1000 NTU
Formazin standards greater than 80 NTU must have a difference of at
least 60 NTU.
Change the calibration points
When using user-selected values of formazin standards during
calibration, change the calibration points that are shown on the display
as they occur. Change the calibration points so that they agree with the
turbidity of the user-defined values.
For example: A 25-NTU standard is put in the sample cell holder
instead of the recommended 20-NTU standard during calibration.
Change the "20.000" on the display to "25.000" before pushing ENTER
to start the measurement.
To change the value on the display during calibration:
1. Push the right arrow key. The decimal point flashes.
2. Push the right arrow key to move the cursor to the next position.
3. Push ENTER to accept the new cursor position.
4. Use the up and down arrow keys to change the number on the
display.
5. Do steps 2–4 again if necessary to change the other digit.
6. Push ENTER to save the change and start the measurement.
Maintenance
D A N G E R
Multiple hazards. Only qualified personnel must conduct the tasks
described in this section of the document.
Clean the instrument
Keep the instrument clean to get continuous and accurate operation.
N O T I C E
Never use cleaning agents such as turpentine, acetone or similar products to
clean the instrument including the keypad.
1. Turn the instrument off and disconnect the power cord.
2. Clean the surface of the instrument with a soft, moist cloth and a
weak soap solution.
3. Dry the surface of the instrument with a lint-free cloth.
Replace the LED light source
The light source, light emitting diode (LED), is not user replaceable.
Contact Customer Service for LED replacement.
Replace a fuse
Fire hazard. Use the same type and current rating to replace fuses.
Replacement parts:
• Fuse for 115 V operation, time-delay, 250 V, 1.6 A (3030700), or
• Fuse for 230 V operation, time-delay, 250 V, 1.6 A (3030600)
D A N G E R
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33
To replace a fuse, refer to the illustrated steps in Figure 10.
Figure 10 Replace a fuse
Troubleshooting
Refer to the tables in this section for error codes, diagnostic codes,
common problem messages or symptoms, possible causes and
corrective actions.
Error codes
Table 6 lists the error codes shown for different conditions. Error codes
identify instrument malfunction or operator error.
The instrument continues operation in an error condition.
Push ENTER to clear an error code from the display.
Note: Any calibration being calculated when an error occurs, is discarded. The old
calibration is kept.
Table 6 Error codes
ErrorDescriptionSolution
ERR01 The turbidity of the
dilution water is greater
than 0.5 NTU.
ERR02
• Two calibration
standards have the
same value.
• The difference
between two
calibration standards
is less than
60.0 NTU.
• The turbidity of
Standard 1 is too
low (less than
10 NTU).
ERR03 Low light error
ERR04 Memory malfunction
ERR05 A/D is over the range
Start the calibration again with lower turbidity
dilution water.
Note: Ignore ERR01 when the sample cell diameter
is less than 25 mm. Push UNITS/Exit to go back to
measurement mode.
1. Inspect the preparation of standards.
2. Do the calibration again.
Note: Ignore ERR02 when the sample cell diameter
is less than 25 mm. Push UNITS/Exit to go back to
measurement mode.
1. Put the sample in the instrument again.
2. Make sure that the lamp light is on.
3. Make sure that an object is not in the light
path.
4. Do sample dilution if necessary.
1. Turn the instrument off and then back on.
2. Contact Technical Support if the error
occurs again.
1. Make sure that the light shield is closed.
2. Contact Customer Service if necessary.
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Table 6 Error codes (continued)
ErrorDescriptionSolution
ERR06 A/D is under the range
ERR07 Light leak
1. Make sure that no object is in the light
path.
2. Contact Customer Service if necessary.
1. Make sure that the cover for the sample
cell compartment is closed.
2. Turn the instrument off and then back on.
Note: To print a diagnostic report, hold down PRINT, then turn the instrument on.
Table 7 Diagnostic codes
CodeDisplayDescription
21 Pr InPrinter test
22 Test results are shown.Display test
23 Test results are shown.Keyboard test
24 Test results are shown.Memory test
ERR09 Printer time out error
ERR10 System voltage out of
range
ERR11 System loop test error
1. Make sure that the external printer is
connected correctly.
2. Make sure that the external printer is
selected (online).
1. Turn the instrument off and then back on.
2. Contact Customer Service if the error
occurs again.
1. Turn the instrument off and then back on.
2. Contact Customer Service if the error
occurs again.
Diagnostic codes
Table 7 lists the diagnostic codes that are used to get information about
instrument operation when instrument operation is in doubt.
To do a diagnostic test:
1. Push SETUP.
2. Use the arrow keys to enter a diagnostic code.
3. Push ENTER to show the diagnostic value.
4. Push UNITS/Exit to go back to Measurement mode.
Delete calibration data
To delete any calibration data entered by the user:
1. Turn off the instrument.
2. Push and hold CAL.
3. Turn on the instrument.
The CAL? light flashes. The instrument starts in Calibration mode.
4. Calibrate the instrument before use.
Flashing 9s
When manual ranging is selected, the display will flash all 9s when the
sample being measured is greater than the selected range.
When automatic ranging is selected, the display will flash 9s when the
sample is greater than the maximum range of the instrument.Refer to
Measure over-range samples on page 22.
Flashing 0s
When manual ranging is selected, the display will flash all 0s when the
sample measured is less than the selected range.
When automatic ranging is selected, the display will flash all 0s when the
measurement is less than the range of the instrument or a negative
value. Calibrate the instrument.
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Replacement parts and accessories
Note: Product and Article numbers may vary for some selling regions. Contact the
appropriate distributor or refer to the company website for contact information.