Sherwood Scientific 926 Operator's Manual

926 91 000 Issue 2 8th August 2012 ECN 758

G:\DOCUMENT CONTROL\Manuals\Chloride\926\92691000 Sherwood M926 Operator Manual Issue 2.docx

Model 926

Chloride Analyser

Operator’s

Manual

Sherwood Scientific Limited

1 The Paddocks

Cherry Hinton Road

Cambridge

CB1 8DH

UK

Copyright© 2012 Sherwood Scientific Ltd.

Model 926 Chloride Analyser

926 91 000 Issue 2 8th August 2012 ECN 758 2

Contents

page

1 Introduction

1.1 Introduction ………………………………. 4

1.2 Summary of Test …………………….. 4

1.3 Reagents ………………………………. 5

Dilution
Storage
Purification
Instability

2 Installation

2.1 Services Required …………………….. 6

2.2 Unpacking ………………………………. 6

2.3 Assembly ………………………………. 7

3 Principles of operation

3.1 Description ………………………………. 8

4 Performance characteristics and specifications

4.1 Range ……………………………………….. 9

4.2 Accuracy ……………………………… 9

4.3 Linearity ……………………………… 9

4.4 Reproducibility ……………………………… 9

4.5 Stability …………………………….. 9

4.6 Response time …………………………….. 9

4.7 Measurement capacity …………………… 9

4.8 Samples …………………………….. 9

Type
Presentation
Volume

4.9 Readout …………………………….. 10

4.10 Warm up …………………………….. 10

4.11 Environmental conditions ………….. 10

Operation
Transportation
Installation category

4.12 Power requirements ……………………. 10

4.13 Size ………………………………………… 10

4.14 Weight ………………………………………… 10

5 Operating Instructions

5.1 Controls and indicators ……………………… 11

Condition
Titrate
Select Units

5.2 Rear panel components …………… 12

Power switch
Power
RS232 socket
USB A socket
USB B socket

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Contents

Page

5.3 Operation ………………………………. 13

5.4 RS232 Output and Printing …………... 14

5.5 USB B Output …....…........................... …. 15

5.6 Active Salt Software Package …………… 15

6 Operating precautions and hazards

6.1 Operating precautions ………………………. 16

6.2 Hazards ………………………………… 16

7 Quality control

7.1 General ………………………………… 16

7.2 Quality control checks ………………………. 16

8 Maintenance

8.1 General ………………………………… 18

8.2 Daily ………………………………………….. 18

8.3 Electrode cleaning and replacement ……. 19

9 Troubleshooting

9.1 Display not illuminated ……............. 20

9.2 On-screen messages ……............. 20

9.3 Non-reproducible results …………….. 20

9.4 Reproducibly high or low results …... 20

9.5 Non-reproducible results …................ 20

10 Spares and accessories

10.1 Ordering information ……………………… 21

10.2 Spares and accessories ……………. 21

11 Warranty statement …………………………………………. 22,23

Model 926 Chloride Analyser

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1 Introduction

1.1 Introduction

The M926 is a direct reading, digital chloride meter. It is designed for fast and
accurate determinations of Chloride levels in industrial samples.
Sample volume is 0.5ml and results are displayed on a digital readout in mg/l
(milligrams per litre Chloride) or mg% (milligrams percent) salt as Sodium Chloride.

This manual presents complete instructions for setting up and using the M926. A
short time spent familiarising yourself with these instructions will be more than repaid
in satisfactory operation.

The M926 is intended for use by persons knowledgeable in safe laboratory practices.
If the M926 is not used in accordance with these instructions the protection provided
by the equipment may be impaired.

A Service Manual is available as an optional extra, for use by appropriately qualified
technical personnel. Please refer to Section 10.2

1.2 Summary of the Test

The M926 is used for the determination of chloride ions. It is an instrumental
analogue of ”Argentimetry”, the traditional titrimetric methods using Silver Nitrate
reagent. Like these classical methods it relies on the chemical formation of the very
insoluble salt, Silver Chloride. The importance of chloride determination has been
realised for well over a century, with many variations and changes being made to the
techniques in order to improve the detectability and selectivity. Research into the
analysis of chloride was conducted by Gay-Lussac (1832), Levol (1853), Mohr (1856)
and Volhard (1874) and their findings have proven to be the basis of the methods that
are still in common use today.

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Introduction

continued

1.3 Reagents

The following solutions are recommended for use with the M926. Ordering
information is given in Section 10.2.

NOTE All reagents contain preservatives where required.
Standard Solution is 200mg/l. Chloride.
Combined Acid Buffer Solution is a support electrolyte consisting of a mixture of

Acetic and Nitric acids which maintains the correct pH for the complete cycle of
titrations, and a colloid to hold precipitated silver chloride in suspension.

WARNING Acid Buffer is an irritant – avoid contact with skin. Wash exposed

areas with water.

Dilution

No dilution is required for Sherwood Scientific reagents.

Storage

Solutions should be stored away from direct sunlight in a cool place, preferably with
an ambient temperature below 25°C (77°C). Do not us e solutions after the expiration
date shown on the bottle. Do not return decanted contents to the original bottle. Caps
of standard solution bottles must be done up firmly to prevent evaporation.

Purification

No purification or treatment is required when using Sherwood Scientific reagents.

Instability

Never leave bottles of Standard Solution uncapped, as prolonged exposure to the
atmosphere will affect the solution’s concentration.

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2 Installation

2.1 Electrical Supply

The M926 operates at low voltage (12 Volts d.c.). The universal mains adapter
supplied with the M926 comes with a range of plugs to suit most a.c. supplies around
the world. The a.c. supply can be in the range 100 – 240V, 50 – 60Hz.

2.2 Unpacking

Upon receipt, the M926 should be removed from its carton and inspected for damage.
Contact your Sherwood Scientific representative if any items are missing or
damaged.

1. Lift out the accessory tray.

2. Lift the instrument out of the polythene cover on to a bench.

3. Check the instrument and all the items in the carton for signs of damage.
Check items received against the following list and notify your Sherwood
Scientific representative if any discrepancies are discovered.

IMPORTANT Quantities shown in the following list are those supplied with a new

instrument. DO NOT re-order from this list; instead refer to Section 10 of this
manual.

Part No. Description Quantity
001 53 313 Universal mains adapter 1
001 09 006 USB lead, A(M) – B(M), 1.8m 1
001 56 203 Chloride Standard Solution, 200mgCl/l, 1 x 100ml 1 bottle
001 56 205 Silver Electrode Polish 1 vial
001 56 208 Combined Acid Buffer Solution, 1 x 500ml 1 bottle
925 11 002 1 x Cathode, 2 x Detector Electrode, set of 3 1 set
925 11 003 Anodes, pack of 3 1 pack
926 11 001 Beaker, plastic, graduated at 14ml, Sherwood 2
925 14 001 Stirrer 1
926 00 009 Chloride Meter 926 Industrial 1
926 09 051 Lead, M926 to Printer/Computer 1
926 66 005 USB Driver Utility CD 1
926 91 000 Operators Manual 1

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Installation

continued

2.3 Assembly

1. Fit the two shorter, sleeved electrodes into the two rear positions on the
underside of the electrode head, Item 3, Figure 2.1. Ensure both electrodes are
pushed firmly into their sockets behind the protective rubber boots.

Figure 2.1 Electrode Head

1. Cathode, 2. Anode, 3. Detector electrodes, 4. Stirrer.

2. Insert the stirrer through the stirrer hole and push it firmly into its coupling, as
shown in Figure 2.1, Item 4.

3. Insert the cathode (un-sleeved, short electrode) through the left-hand hole and
push it firmly into its socket, as shown in Figure 2.1, Item 1.

4. Fit an anode (70mm long electrode) through the remaining hole into its socket.

5. Check that the three shorter electrodes are all fully inserted and then adjust the
position of the anode so that all four electrodes are the same length.

6. Position the M926 so that there is clear access to the on/off switch (Item 1,
Figure 5.2, page 12).

7. The universal mains adapter supplied with the M926 comes with a range of
plugs to suit most a.c. supplies around the world. Choose and fit the one that
suits your local electricity supply.

8. Refer to Section 5 of this manual for detailed operating instructions.

1

2

4

3

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3 Principles of Operation

3.1 Description

An accurately measured volume of sample (0.5ml) is added to an acid buffer. The
M926 automatically titrates chloride ions by passing a known constant current
between two silver electrodes which provides a constant generation of silver ions.
These silver ions combine with the chloride in the sample to form silver chloride,
which is held in suspension by the colloid stabiliser. During the titration period the
digital readout is updated approximately every 0.3 seconds. During these periods the
number of silver ions introduced into the sample combine with one unit measurement
of chloride. When all the chloride has been precipitated as silver chloride, free silver
ions begin to appear and the solution conductivity changes. This change is detected
by the detector electrodes and the readout is stopped, displaying the results directly
in milligrams per litre of Chloride or milligrams % salt as Sodium Chloride. Another
sample may now be added to the same acid buffer and the cycle repeated. The
digital display is held until starting another cycle, when it is automatically reset to
zero.

NOTES

1. The M926 uses an absolute method of operation and is calibrated at the
factory. Recalibration should only be necessary after changing internal
electronic components.

2. The mg% salt value is obtained from the mg/l Chloride result by a fixed
calculation. This calculation is only correct for sample/diluent ratios
equivalent to 1gm. sample per 100ml. diluent used to 'dissolve/dilute' the
sample.

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4 Performance Characteristics and Specifications

4.1 Range

10 to 999mg/l Chloride or 2 to 165mg% salt. See Note 2. on page 8 for more on mg%
salt.

4.2 Accuracy

Results will be within ±2mg/l (at the 100mg/l level) of the values obtained by standard
wet-chemical methods after allowing for pipetting errors.

4.3 Linearity

Results will be within ±3mg/l in the range 50 to 299mg/l.

4.4 Reproducibility

The values obtained from five consecutive titrations of a nominal 200mg/l solution will
be within 3mg/l of the mean value.

4.5 Stability

The calibration level (mean of five titrations of a standard solution) will change by less
than ±2 Least Significant Digits over the life of any silver anode.

4.6 Response Time

A stable reading will be displayed within 36 seconds of pressing the ‘titrate’ button, at
a concentration level of 200mg/l.

4.7 Measurement Capacity

Seven industrial samples at 0.5ml volume, per reagent change.

4.8 Samples

Type

Chloride in solution, having low ionic strength, neutral pH and free of silver halides,
silver reactive constituents (other than chloride), solid matter and high levels of
dissolved solids.

Presentation

By pipette directly into the beaker of Sherwood Scientific combined acid buffer.

Volume

0.5ml

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Performance Characteristics and Specifications

continued

4.9 Readout

Measurement results are shown in characters 15mm. high on a 2.75” 60 dpi backlit
LCD screen. Separate areas of the display are reserved for measurement units and
instrument status information.

4.10 Warm Up

Five minutes warm up is required to meet the stated specification.

4.11 Environmental Conditions

Operation

Temperature range +10°C to +35°C
Maximum relative humidity 85% at +35°C (non condensin g)

Transportation

Temperature range -40°C to + 45°C
Maximum relative humidity 95% at +45°C

Compliance with the stated specification will be unaffected by a change in ambient
temperature up to 4°C per hour, provided the operat ing temperature range is not
exceeded.

Installation Category

Installation category 1.

4.12 Power requirements

Mains adapter Input

100V – 240V ~, 50Hz – 60Hz, 0.6A

Mains adapter Output

12V … 1.25A

4.13 Size

Width 200mm (7”)
Depth 250mm (9.8”)
Height 315mm (12.4”)

4.14 Weight

1.9kg (4.2lbs)

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5

Operating Instructions

5.1 Controls and Indicators

Figure 5.1 Front Panel

1. Display screen, 2. '

titrate'

button, 3. '

condition

' button, 4. '

select'

Units button.

'

condition

'

Pressing this button initiates a conditioning cycle. The purpose of the conditioning
cycle is to titrate out any Chloride present in the buffer or beaker, so that the
subsequent titration is accurate. The conditioning cycle must be run each time the
M926 is switched on and each time the buffer is changed, usually when 'Change

Buffer And Condition/ Condition Required' is displayed.

'

titrate

'

Pressing this button initiates a titration cycle. During a titration the stirrer operates for
approximately 5 seconds before the readout is set to zero. The Chloride is then
titrated out of the solution while the readout is incremented. When all the chloride is
titrated the readout is stopped and held. The ‘titrate’ button is inoperative at switch on
and when 'Change Buffer And Condition/ Condition Required' is displayed, usually
after the allowed maximum number of consecutive samples (7) have been titrated. In
each case this ensures that a condition cycle is carried out first. This prevents an
erroneous result on the first titration due to chloride being present in the buffer or
beaker.

'select'

Units

The 'select' button allows the user to choose the units in which the result of a titration
is displayed. The M926 carries out measurements in units of mg/l Chloride and only
calculates the final result in mg% salt when this is the unit on the display. This button
only operates after a condition cycle.

Press Titrate

100

mmol/l (20µl)

1

2

3

4

select

condition

titrate

S

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Operating Instructions

continued

5.2 Rear Panel Components

Figure 5.2 Rear Panel and Label detail

1. Power switch On/Off toggle switch that switches the d.c. supply from the
mains adapter to the instrument. 0 for Off, 1 for On.

2. Power Input socket for d.c. lead from mains adapter to the
instrument.

3. RS232 socket Input connector for Serial Cable (926 09 051).

4. USB A socket To accept a memory stick for future firmware upgrades.

5. USB B socket Connector for USB Cable (001 09 006) as an alternative for
connecting to computers that do not have an RS232 serial
comms. port.

1

2 3 4 5

A

B

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Operating Instructions

continued

5.3 Operation

1. Connect power, switch on and allow 5 minutes for the M926 to warm-up.

2. Fill a plastic beaker, supplied, to the mark with combined acid buffer, place the
beaker on the platform and raise the platform until it locates in the up position.

3. Pipette 0.5ml of 200mg/l standard solution into the beaker.

4. Press the 'condition' button and wait for the condition cycle to complete.

5. Pipette 0.5ml of sample into the beaker and press the ‘titrate’ button.

6. When the stirrer stops, note the reading on the display. If the results are
required in mg% salt depress the 'select ' button so that mg% salt is shown in
the units area at the bottom of the display screen. See note 2, page 8.

7. Repeat paragraphs 5 and 6 for further samples.

8. At the end of the 5th titration, the message ‘Condition in 2’ will appear on the
display. At the end of the 6th titration ‘Condition in 1’ will appear on the
display.

IMPORTANT When the 7

th

titration is complete any further sample added will be
lost. “Change Buffer And Condition/ Condition Required” will be
displayed on the screen and the 'titrate' button will have no effect.
Go to paragraph 9 below.

9. When “Change Buffer And Condition/ Condition Required” is displayed, lower
the beaker and empty out the contents. Rinse with deionised water and dry
with clean tissue.

10. If necessary, adjust the vertical position of the anode, Item 2, Figure 5.3, so
that it is the same length as the other electrodes.

11. If more samples are to be titrated return to paragraph 2 near the top of this
page.

12. When determinations are complete, remove the beaker and dry the
electrodes and stirrer by blotting with a clean tissue.

Figure 5.3

Electrodes and Electrode Head

1

2

4

3

1. Cathode

2. Anode

3. Detector electrodes

4. Stirrer

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Operating Instructions

continued

5.4 RS232 Output and Printing

The M926 has an RS232 output that enables results to be sent to external printers,
such as the Portable Printer (473 56 903), or other devices with serial inputs.

1. A Serial Cable (926 09 051) is provided if you wish to use an external device.
The small, round end of the cable fits into the socket on the rear of the M926
(Figure 5.2, Item 3) and the other end into the serial input socket of the
external device - a printer or a computer serial interface.

2. Adjust the serial comms. settings of the external device to 9600 8-N-1.

3. Direct printing from the Model 926.

Switch on the external device then switch on the M926. After the initialisation
sequence the software version (e.g. v0.24) and serial number (e.g. 16555)
are shown on the display screen for approximately 5 seconds. The printer will
print :-

4. Perform measurements as described in Section 5.3. After each titration the
printer will print the screen value as: -

or, if mg% salt was the measurement unit on screen at the start of the
titration:-

During and after the conditioning cycle there is no signal to the printer as
conditioning can be necessary during the measurement run of samples. The
sample number sequence is thus uninterrupted.
The number sequence on a printer can be reset to ‘001’ only by switching off
the M926 and reconditioning.

Sample 001 = 200 mg./l.
Sample 002 = 202 mg./l.
Sample 003 = 201 mg./l.

Sample 004 = 034 Salt
Sample 005 = 033 Salt

926 Chloride Meter

Serial Number: 16555
Software Version: 0.24

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Operating Instructions

continued

5.5 USB B Output

The M926 also has USB B port that enables results to be sent to computers that do
not have an RS232 serial comms. port. A USB cable (001 09 006) is provided. The
squarer end fits into the socket on the rear of the M926 (Item 5, Figure 5.2, page 12).

A PC utilities communications programme such as HyperTerminal is required to
establish a connection with the M926 and receive data from it. Making a connection
requires knowledge of which COM port (7 in the example above) the M926 is on and
the settings 9600 8-N-1.

It will be necessary to load the USB Driver Utility, from the CD provided, on to the
computer so that it will assign a port to the 926.
Load the disc in the disc drive and wait for Autoplay to begin.
If a dialog box does not appear from the toolbar at the bottom of the screen
announcing the driver has been successfully loaded, open Device Manager on the
computer.
Connect the 926 to the computer with the USB Cable and switch it on.
926 Chloride Analyser will appear under ‘other devices’.
Highlight this and right click.
Select ‘Update Driver’ from the menu.
Browse to locate the file on the disc drive and click ok.
When the installation is complete the Device Manager will update and under Ports
(COM & LPT) the M926 will typically appear as - 926 Series Chloride Analyser
(COM7).
Make a note of the COM number.

Please note that if the instrument is turned off while the communications programme
(e.g. HyperTerminal) is active, it will be necessary to close and re-launch the
programme after the instrument is switched back on to re-establish communications.

5.6 Active Salt Software Package

The Sherwood Scientific Active Salt package has been developed to enhance the
Model 926 Chloride Analyser. Designed initially for the Cheese industry the package
may be applied to any food product requiring salt analysis and documentation; as the
software may be configured by the operator to suit their particular laboratory
requirements. Designed to collect data directly from a balance with RS232 output and
the Chloride analyser: some of the advantages are:-

No transcription errors.
No timed wasted doing manual calculations.
No need to be achieve specific sample and diluent weights.
Automatic data storage and analysis report generation.
For further detailed information contact your Sherwood Scientific distributor.

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6 Operating Precautions and Hazards

6.1 Operating Precautions

1. The electrodes may go black during use; this will not affect the performance.
Only if the M926 will not measure a Standard or sample will it be necessary
to clean the electrodes.

2. The M926 requires a warm up period of five minutes to meet the stated
specification.

3. Reproducibly accurate results are dependent on reproducible pipetting from
sample to sample and from aqueous standard to sample. If the M926
calibration is checked with an aqueous standard and reproducibly low results
are obtained, hold up in the pipette should be suspected and a rinse out
technique employed.

4. Always dispense standard solution into a small beaker or cup. Do not take
standard solution directly from the bottle with a pipette, as the standard could
become contaminated. Never pour standard solution back into the bottle once
it has been dispensed. Ensure that only genuine Sherwood Scientific
reagents and supplies are used with the M926. Do not use solutions after the
expiry date shown on the bottle.

5. Samples should have low ionic strength, neutral pH and be free of sulphide,
sulphydryl silver halides, silver reactive substances (other than chloride),
solid matter and high levels of dissolved solids.

6. Do not leave the electrodes immersed in reagents when the instrument is not
in use.

7. Use only the beakers supplied with the M926.

8. It is recommended laboratory practice to wear gloves when handling
samples. Gloves will also afford protection against the Combined Acid Buffer
and against accidental static damage to the electrodes.

6.2 Hazards

1. All electrical equipment is potentially hazardous. Never remove covers from
the M926 without first ensuring that it is isolated from the a.c. supply.

2. Do not move the M926 when there is a beaker containing Combined Acid
Buffer in position on the sample platform.

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7 Quality Control

7.1 General

The M926 Chloride Analyser has been designed to provide fast and accurate
determinations of Chloride in industrial solutions.

The latest Sherwood Scientific technology has been incorporated into the M926 to
ensure the validity of the final results. However, the results can be affected by factors
other than instrument malfunction, such a sample handling and storage. Sherwood
Scientific recommend therefore that a Quality Control programme is set up to monitor
instrument and operator performance. Because the needs of each laboratory are
different, due to size of workload, number of hours worked, statutory regulations, etc.,
no attempt has been made to formulate a rigid programme. Instead, in Section 7.2
there are a number of suggestions that will be helpful in specifying a procedure to suit
your particular requirements.

The following references are recommended for further information on Quality Control.

BS600:2000 A guide to the application of statistical methods to quality and

standardization.

ISBN 058033227 6

Westgard, J.O., Clinical Chemistry 54:612, 200

IMPORTANT If you report your results to a Quality Control Scheme ensure that

they are informed of the change in method, i.e. Sherwood Scientific
926 Chloride Analyser.

7.2 Quality Control Checks

The following notes are designed to assist you in formulating a Quality Control
programme.

1. Include a Quality Control as specified in your Quality Control Scheme or at
least once per sample run, once per day or every 40 samples.

2. Check abnormally high and low values daily.

3. Routinely include aqueous Standards that contain chloride concentrations
that are different to the Standard concentration used for calibrating the M926.

4. Ensure day-to-day variations do not exceed acceptable values.

5. Reproducibility should be checked on 5 replicate samples on a routine basis.

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8 Maintenance

8.1 General

The M926 has been designed to reduce the need for regular maintenance to an
absolute minimum. The maintenance required is detailed in Section 8.2, Daily. Refer
to Section 10 for ordering information and catalogue numbers of parts used for daily
maintenance, which are listed under Equipment Required.

8.2 Daily

Equipment Required

Disinfectant Solution
electrode polish
1 x anode
1 x cathode
2 x detector electrodes

1. Check that all four electrodes are straight and parallel and the anode is the
same level as the other electrodes. If necessary, refer to Section 8.3 to clean,
adjust or replace the electrodes.

2. Check that the stirrer is present and is fitted firmly into its coupling.

3. Wipe down the sample area with disinfectant solution.

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Maintenance

continued

8.3 Electrode Cleaning and Replacement

Equipment Required

Electrode polish, soft cloth, 1 x cathode, 1 x anode and 2 x detector electrode.

1. Remove the four electrodes by withdrawing them downwards from the

electrode head.

NOTE that the anode (Item 2, Figure 8.1) is longer than the other three electrodes.

Figure 8.1 Electrodes and Electrode Head

1. Cathode, 2. Anode, 3. Detector electrodes, 4. Stirrer.

2. If the length of the anode is less than 57mm discard it and fit a replacement.

3. Place a little Electrode Polish on a soft cloth and gently rub the exposed parts

of the electrodes until they are clean and bright.

4. Refit the electrodes; ensure that with the cathode and Detector electrodes

fully inserted, the anode is adjusted to the same length.

5. Place a beaker of deionised water on the sample lift and immerse the

electrodes.

6. Carry out three condition cycles.

7. Remove the beaker and wipe the electrodes with a clean soft cloth.

8. Carefully inspect the electrodes to ensure that they are clean. If they are not

repeat paragraphs 1 to 7. If they are still not clean fit replacements, ensuring
that they are fully inserted.

9. Check that all the electrodes are straight and parallel, adjusting as necessary.

1

2

4

3

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9 Troubleshooting

9.1 Display not illuminated

Check that the instrument is connected to a working a.c. supply, and that the power
switch is in the on position.

If the fault persists contact your Sherwood Scientific distributor.

9.2 On-screen messages

These self-explanatory alerts may appear at the top of the display screen.

Shown at start-up and after seven consecutive
samples have been titrated.

Shown after the 5th consecutive titration.

Shown after the 6th consecutive titration.

Shown if electrodes are not in liquid.

999 mg./l has been exceeded. Check sample
dilution and that the pipette is dispensing 0.5ml.

Conditioning took too long. Too much Chloride in
beaker. Stirrer not present or not turning.

9.3 Condition or titrate cycle inoperative

Check the beaker contains Chloride; add 0.5ml of standard solution if necessary.
Clean or replace the electrodes, refer to Section 8.3.
Make sure that the cathode electrode is fully inserted into its socket.
If the fault persists contact your Sherwood Scientific distributor.

9.4 Reproducibly high or low results

Try using a fresh bottle of standard solution and another pipette.
Check that carry over in the pipetting is avoided by using a rinse out technique for
each sample.
If the fault persists contact your Sherwood Scientific distributor.

9.5 Non-reproducible results

The M926 requires a five minute warm up to meet the stated specification.
Try another pipette. (Ensure the pipette is reproducible to 0.5% Standard Deviation).
Clean or replace the electrodes, refer to Section 8.3.
Use a fresh bottle of Sherwood Scientific Combined Acid Buffer.
If the fault persists contact your Sherwood Scientific distributor.

Change Buffer / And Condition

Condition Required

Add Sample / Press Titrate

Condition in 2

Add Sample / Press Titrate

Condition in 1

Out of Solution / Check Buffer

Condition Required

Reading 999+ / Check Sample

Condition Required

Condition cycle timed out

Refer to Operator Manual

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10 Spares and Accessories

10.1 Ordering Information

When ordering spares or accessories for the M926 please give the following
information to your Sherwood Scientific representative: -

Serial number
Catalogue number of part (Cat. No.)
Description
Quantity required

This will ensure that your order is dealt with quickly and efficiently.
The number shown in the third column (Quantity) is the quantity of items that are

supplied against the stated catalogue number. If the quantity is greater than one then
only multiples of that quantity can be supplied.

10.2 Spares and Accessories

Cat. No. Description Quantity
001 56 208 Chloride Analyser Combined Acid Buffer, 1 x 500ml 1 bottle
001 56 203 Chloride Analyser Standard, 200mg/l Cl, 6 x 100ml 1 pack
001 56 205 Silver Electrode Polish, 25g 1 vial
473 56 903 Printer Assembly, Universal 1
473 59 700 Printer consumables kit 1 pack
925 11 002 1 x cathode and 2 x detector electrode, set of 3 1 set
925 11 003 Anodes, pack of 3 1 pack
926 11 001 Beaker, plastic, graduated at 14ml, Sherwood 1
925 14 001 Stirrer, 20mm 1
926 89 001 Service manual 1
926 86 500 Active Salt Software Package 1
001 53 313 Universal Mains adapter 1
926 66 005 USB Driver Utility CD 1

Model 926 Chloride Analyser

926 91 000 Issue 2 8th August 2012 ECN 758 22

11

Sherwood Scientific Limited
Product Warranty Statement

_________________________________________________________________________________________

Warranty Term: 12 Months

Sherwood Scientific Ltd (Sherwood) warrants, subject to the conditions itemised
within this document, through either Sherwood personnel or personnel of its
authorised distributors, to repair or replace free of all charges, including labour, any
part of this product which fails within the warranty time specified above, appertaining
to this particular product. Such failure must have occurred because of a defect in
material or workmanship and not have occurred as a result of operation of the
product other than in accordance with procedures described in the instructions
furnished with this product.

Conditions and specific exceptions that apply to the above statement are as follows:

1. End-user warranty time commences on the date of the delivery of product to
end-user premises.

2. ‘Free of all charges’ statement applies only in areas recognised by Sherwood
as being serviced either directly by its own personnel, or indirectly through
personnel of an authorised distributor. Products purchased outside these
areas requiring service during the warranty period will incur charges relative
to the travel/transit costs involved. However, products purchased in such
areas will be serviced during the warranty period free of all charges providing
they are returned, carriage paid, to either Sherwood or by pre-arrangement to
an authorised Sherwood distributor.

3. All maintenance (other than operator maintenance as described in the
instructions), repairs or modifications have been made by Sherwood or
Sherwood authorised personnel.

4. This product has where applicable been operated using Sherwood specified
supplies and reagents.

5. Sherwood reserves the right to make any changes in the design or
construction of future products of this type at any time, without incurring any
obligation to make any changes whatsoever to this particular product.

6. Reagents, supplies, consumables, accessories and user maintenance items
are not included in this warranty.

Model 926 Chloride Analyser

926 91 000 Issue 2 8th August 2012 ECN 758 23

Product Warranty Statement (continued)

7. Repairs or replacement of any part failing due to abnormal conditions
including the following, are excluded from this warranty:

a. Flood, lightning, earthquake, tornado, hurricane, or any other natural

or man-made disaster.

b. Fire, bombing, armed conflict, malicious mischief or sprinkler

damage.
c. Physical abuse, misuse, sabotage or electrical surge.
d. Damage incurred in moving the product to another location.

User agrees to permit Sherwood personnel or personnel of its authorised distributor
to make changes in the product which do not affect results obtained, but do improve
product reliability.

Representations and warranties purporting to be on behalf of Sherwood made by any
person, including distributors and representatives of Sherwood, which are
inconsistent or in conflict with the terms of this warranty (including but not limited to
the limitations of the liability of Sherwood as set forth above), shall not be binding
upon Sherwood unless reduced to writing and approved by an officer of Sherwood
Scientific Ltd.

Except for the obligations specifically set forth in this warranty statement, in no event
shall Sherwood be liable for any direct, indirect, special, incidental, or consequential
damages, whether based on contract, tort or any other legal theory and whether
advised of the possibility of such damages.

Neither Sherwood nor any of its third party suppliers makes any other warranty of
any kind, whether expressed or implied, with respect to Sherwood Products.

Sherwood Scientific Ltd.,
1 The Paddocks,
Cherry Hinton Road,
Cambridge,
CB1 8DH,
England