YSI 5905 Operating Manual

YSI 5905, 5010,
200-BOD, and
Pro-BOD Probe
Instruction Manual

TABLE OF CONTENTS

I

NTRODUCTION ................................................................ 1

OPERATING PRINCIPLES .......................................................2

USING THE PROBE ............................................................. 3

Changing the Membrane Cap....................................................3

Warm Up.....................................................................................5

Electrode Cleaning...................................................................... 5

OPERATING PROCEDURES AND PRECAUTIONS ............................ 7

Air Calibration ............................................................................7

Checking the Probe Zero............................................................ 7

Membrane Life............................................................................ 7

Interferences................................................................................ 8

Acids ............................................................................................ 8

Erroneous Readings.................................................................... 8

Storage......................................................................................... 8

PROBLEM SOLVING ............................................................ 9

Trouble Shooting Guide.............................................................9

SERVICING..................................................................... 11

WARRANTY AND REPAIR ..................................................... 13

Authorized Service Centers...................................................... 14

Cleaning Instructions ...............................................................14

Packing Instructions................................................................. 15

PROBE SPECIFICATIONS .....................................................17

APPENDIX A ................................................................... 18

APPENDIX B ...................................................................19

i

INTRODUCTION

The YSI Model 5905/5010/200-BOD/Pro-BOD (Biochemical
Oxygen Demand) probe is used for measuring dissolved oxygen
in all popular size BOD bottles. These probes feature self stirring,
easily replaceable membrane caps, and a refurbishable electrode
system.

The 5905 probe is designed for use with all YSI grey-box-style
dissolved oxygen meters, except for the Model 55 or Model 550A.
It must be used with an adapter (5011) in order to be used on the
Model 5000 and 5100 bench top instruments.

The 5010 probe is specifically designed for use with the Model
5000 and 5100 only.

The 200-BOD probe is specifically designed for use with the
Model DO200 only.

The Pro-BOD probe is specifically designed for use with the
Pro20 and Professional Plus instruments.

This manual also applies to probes 5905-J, 5905-K, 5905-L, 5905­W (Appendix A), and probes 5010-J, 5010-K, 5010-L, and 5010­W (Appendix A)

---IMPORTANT---

Intended Use

The 5905/5010/200-BOD/Pro-BOD probe is intended for
laboratory use, not field use. It is not waterproof and should
never be immersed past the taper on the stem of the probe.

1

OPERATING PRINCIPLES

The 5905/5010/200-BOD/Pro-BOD probe is a polarographic
dissolved oxygen sensor. An oxygen permeable membrane covers
an electrolytic cell consisting of a cathode and an anode. This
membrane acts as a diffusion barrier and an isolation barrier
preventing the fouling of the cathode surface by impurities in the
environment. The cathode is the gold electrode, and the anode is
the silver electrode which completes the electrolytic cell and acts
as a reference electrode.

Upon entering the cell through the membrane, oxygen is reduced
at an applied potential of -0.8 V referenced to the silver electrode.
The reduction current at the cathode is directly proportional to
the partial pressure of oxygen in liquid (expressed as %-air
saturation) which is also proportional to the concentration of
dissolved oxygen (in mg/L) at a particular temperature. Thus the
same partial pressure of oxygen (%-air saturation) in liquid gives
different concentrations of dissolved oxygen (mg/L) at different
temperatures because of the different solubilities of oxygen at
different temperatures.

2

USING THE PROBE

The 5905/200-BOD/Pro-BOD must be plugged into a YSI meter
and the stirrer power plug must be plugged into its power
adapter. The 5010 must be plugged into a YSI meter only, as it
gets its stirring power from the 5000/5100 instrument.

Changing the Membrane Cap

---IMPORTANT---

New Probe Use

New probes are shipped with a dry membrane cap to protect the
electrodes. A new membrane cap must be installed before first
use. For the 5905/5010, use a Teflon membrane from a 5906
Membrane Kit. For the 200-BOD/Pro-BOD, use a PE membrane
from a 5908 Membrane Kit.

Follow these instructions to change membrane caps (Figure 1):

1. Remove the stir paddle from the probe by pulling it straight
out.

2. Unscrew the old membrane cap from the probe. Before
installing a new membrane, clean the probe tip with deionized
water in order to remove any contaminants.

3. Hold the membrane cap and fill it at least ½ full with the
electrolyte solution provided. Screw the membrane cap onto
the probe moderately tight. A small amount of electrolyte
should overflow.

4. Rinse off excess electrolyte from the probe with deionized
water.

5. Reinstall the stir paddle.

3

Remove

Stir Paddle

Fill Membrane Cap

with Solution

Unscrew Cap

Replace

Stir Paddle

Screw Cap on

moderately tight

Figure 1: Membrane Installation on the 5905/5010/200-BOD/Pro­BOD .

4

Warm Up

Every time the instrument is turned on, the 5905/5010/200­BOD/Pro-BOD Probe must be allowed to warm up for about 10­20 minutes before taking the first reading. This allows the probe
to use up all the oxygen retained in the cap.

---IMPORTANT---

New Probe Break In (motor off)

For best results, please allow the probe more than the usual 20
minutes to warm up after the first membrane is installed. The
process may be faster if the probe is allowed to warm up in a
BOD bottle filled with clean water. If possible, it’s a good idea to
let new probes warm up overnight (with a new membrane and
KCl) prior to first use.

Electrode Cleaning

The 5905/5010/200-BOD/Pro-BOD should be cleaned only when
erratic readings occur or after about every 500 hours of use (two
months). Each cleaning removes material and reduces the life of
the probe, so excessive cleaning should be avoided.

Gold Cathode

For correct probe operation, the gold cathode must be textured
properly (for its location, see figure 2). It can become tarnished
or plated with silver after extended use. The gold cathode can be
cleaned by using the sanding disc provided in the 5906 and 5908
Membrane Kits. Place the disc in the palm of your hand, then
sand the gold with a twisting motion about 3 times or until all
silver deposits are removed and the gold appears to have a matte
finish. If the cathode remains tarnished, return the probe for
service.

5

Silver Anode

It is normal for a dark layer of silver chloride to cover the silver
anode (for its location, see figure 2). After prolonged use it may
become necessary to clean the anode. Soak the probe in a 14%
ammonium hydroxide solution for 2 to 3 minutes or overnight in
a 3% ammonium hydroxide solution. Rinse with deionized
water, recharge with electrolyte, and install a new membrane.
The anode may also need a very light sanding with the supplied
sanding discs. Sand lightly in a helical fashion (down and
around), then rinse well with deionized water.

Temperature

Sensor

Anode

(Silver)

Cathode

(Gold)

Figure 2: 5905/5010/200-BOD/Pro-BOD Sensor

6

OPERATING PROCEDURES AND PRECAUTIONS

---IMPORTANT---

Intended Use

The 5905/5010/200-BOD/Pro-BOD probe is intended for
laboratory use, not field use. It is not waterproof and should
never be immersed past the taper on the stem of the probe.

Air Calibration

When calibrating in air, make sure there are no water droplets on
the membrane. Water droplets will cause a low calibration
reading. Excess water may be removed by shaking the probe
downward. If droplets persist it may be necessary to carefully
remove them using a clean cloth or paper towel.

Checking the Probe Zero

The probe zero is checked by immersing the probe in a sodium
sulfite solution (0.08M or 3g Na
has an inert gas bubbling through it (e.g. nitrogen, argon). The
meter should read less than 1% dissolved oxygen in either of
these environments. If it does not, change the membrane or clean
the probe.

/300mL), or in water which

2SO3

Membrane Life

Membrane life depends on use. Membranes will last longer if
installed properly and treated with care during use. Erratic
readings will result from loose, wrinkled, or fouled membranes or
from bubbles larger than 1/8” in the electrolyte solution. If erratic
readings or other evidence of membrane damage occurs, replace
the membrane and KCl solution.

7

The average replacement interval is two to four weeks. Probes in
constant or heavy use may require more frequent membrane
changes.

Interferences

Hydrogen sulfide, sulfur dioxide, halogens, carbon monoxide,
chlorine, nitric oxide, and nitrous oxide can cause the probe to
give erroneous readings. If you suspect erroneous readings, it
may be necessary to determine if these are the cause.

Acids

Avoid any environment that contains substances such as
concentrated acids, caustics, and strong solvents that may attack
the probe. Probe materials that may be damaged by these
substances include FEP Teflon or Polyethylene, EPR rubber, ABS
plastic, and stainless steel.

Erroneous Readings

Erroneous readings may occur if the membrane is coated with
oxygen consuming bacteria or oxygen evolving algae. Heavy
residue may coat the membrane causing incorrect readings.
Frequent membrane changes will eliminate this problem.

Storage

When the probe is not in use, store the probe in a BOD bottle
containing at least 1 inch of water. For long term storage, remove
the membrane cap, rinse the probe tip with deionized water, and
install a dry membrane cap (without electrolyte solution).

8

PROBLEM SOLVING

Trouble Shooting Guide

Use this quick reference table to correct symptoms you might be
experiencing.

Symptoms Actions

Unable to
calibrate

• Allow approximately 20 min. and up to 30

min. for probe to polarize when first turned
on

• Change membrane

• Clean probe (see instructions under Electrode

Cleaning)

Does not return
to calibration
value

Unstable readings

• Allow sufficient time for temperature and

oxygen stabilization

• Check for water droplets on membrane

• Change membrane

• Clean probe (see instructions under Electrode

Cleaning)

• Allow sufficient time for temperature and

oxygen stabilization

• Allow 60 sec for reading to stabilize

• Change membrane

• Clean probe (see instructions under Electrode

Cleaning)

9

Symptoms Actions

Unstable readings • Allow sufficient time for temperature and

oxygen stabilization

• Allow 60 sec for reading to stabilize

• Change membrane

• Clean probe (see instructions under Electrode

Cleaning)

Motor not
working

Loud motor

Membrane cap is
tight

• Check power supply

• Manually turn the stir paddle to help start the

motor

• Replace motor

• Check if stir paddle is pushed all the way in

• Replace motor

• Use pliers to loosen the cap (turn counter

clockwise while facing sensor tip)

10

SERVICING

The 5905/5010/200-BOD/Pro-BOD has four user replaceable
parts. The motor assembly can be replaced if it becomes noisy,
unbalanced, or malfunctions. The probe assembly, housing
assembly, and stir paddle can also be replaced if they become
damaged.

To disassemble the probe, perform the following steps while
referring to figure 3:

1. Remove stir paddle by pulling it straight out.

2. Remove the two screws (A) on the outside of the housing

using a 3/32 Allen wrench.

3. Loosen the top nut of the cable strain relief (B) from the
housing. This will allow the cable to feed through the housing
assembly.

4. Pull the probe and motor assembly out of the housing and
disconnect the two plugs (C).

5. To remove the motor assembly from the probe assembly,
remove the two screws (D) using the 3/32 Allen wrench.

11

(B)

(A)

(D)

Housing Assembly

(A)

(C)

(C)

(D)

Motor Assembly

Probe Assembly

Stir Paddle

Figure 3: Exploded View of 5905/5010/200-BOD/Pro-BOD Probe

12

WARRANTY AND REPAIR

YSI Models 5905/5010/200-BOD/Pro-BOD Dissolved Oxygen Probes are
warranted for one year from date of purchase by the end user against defects in
materials and workmanship. Electrode cleaning or maintenance is not covered
under warranty. Within the warranty period, YSI will repair or replace, at its sole
discretion, free of charge, any product that YSI determines to be covered by this
warranty.

To exercise this warranty, write or call your local YSI representative, or contact YSI
Customer Service in Yellow Springs, Ohio. Send the product and proof of
purchase, transportation prepaid, to the Authorized Service Center selected by
YSI. Repair or replacement will be made and the product returned, transportation
prepaid. Repaired or replaced products are warranted for the balance of the
original warranty period, or at least 90 days from date of repair or replacement.

Limitation of Warranty

This warranty does not apply to any YSI product damage or failure caused by (i)
failure to install, operate or use the product in accordance with YSI’s written
instructions, (ii) abuse or misuse of the product, (iii) failure to maintain the
product in accordance with YSI’s written instructions or standard industry
procedure, (iv) any improper repairs to the product, (v) use by you of defective or
improper components or parts in servicing or repairing the product, or (vi)
modification of the product in any way not expressly authorized by YSI.

THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED
OR IMPLIED, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE. YSI’s LIABILITY UNDER THIS
WARRANTY IS LIMITED TO REPAIR OR REPLACEMENT OF THE
PRODUCT, AND THIS SHALL BE YOUR SOLE AND EXCLUSIVE REMEDY
FOR ANY DEFECTIVE PRODUCT COVERED BY THIS WARRANTY. IN
NO EVENT SHALL YSI BE LIABLE FOR ANY SPECIAL, INDIRECT,
INCIDENTAL OR CONSEQUENTIAL DAMAGES RESULTING FROM ANY
DEFECTIVE PRODUCT COVERED BY THIS WARRANTY.

13

Authorized Service Centers

YSI has several Authorized Service Centers in the U.S. and around
the world. Please refer to the YSI web site (www.YSI.com
nearest Authorized Service Center.

) for your

Cleaning Instructions

NOTE: Before they can be serviced, equipment exposed to
biological, radioactive, or toxic materials must be cleaned and
disinfected. Biological contamination is presumed for any

instrument, probe, or other device that has been used with body
fluids or tissues, or with wastewater. Radioactive contamination
is presumed for any instrument, probe or other device that has
been used near any radioactive source.

If an instrument, probe, or other part is returned or presented for
service without a Cleaning Certificate, and if in our opinion it
represents a potential biological or radioactive hazard, our service
personnel reserve the right to withhold service until appropriate
cleaning, decontamination, and certification has been completed.
We will contact the sender for instructions as to the disposition
of the equipment. Disposition costs will be the responsibility of
the sender.

When service is required, either at the user's facility or at YSI, the
following steps must be taken to insure the safety of our service
personnel.

1. In a manner appropriate to each device, decontaminate all
exposed surfaces, including any containers. 70% isopropyl
alcohol or a solution of 1/4 cup bleach to 1 gallon tap water is
suitable for most disinfecting. Instruments used with waste
water may be disinfected with .5% Lysol if this is more
convenient to the user.

2. The user shall take normal precautions to prevent radioactive
contamination and must use appropriate decontamination
procedures should exposure occur.

3. If exposure has occurred, the customer must certify that

14

decontamination has been accomplished and that no
radioactivity is detectable by survey equipment.

4. Any product being returned to the YSI Repair Center should
be packed securely to prevent damage.

5. Cleaning must be completed and certified on any product
before returning it to YSI.

Packing Instructions

1. Clean and decontaminate items to insure the safety of the
handler.

2. Complete and include the Cleaning Certificate.

3. Place the product in a plastic bag to keep out dirt and packing

material.

4. Use a large carton, preferably the original, and surround the
product completely with packing material.

Insure for the replacement value of the product.

15

Alternatively, if you are planning to send your probe directly to
YSI for servicing, please visit www.ysi.com
the Product Return Form.

16

, download and fill out

Probe Specifications

Cathode: Gold

Anode: Silver

Membrane: FEP Teflon (for 5905/5010)

Polyethylene (for 200-BOD/Pro-BOD)

Dissolved Oxygen Accuracy: ± 0.1 mg/L or ± 2% of reading,

whichever is greater

Operating Temperature Range: 0° to 45°C

Temperature Accuracy: ± 0.2°C

Polarizing Voltage: 0.8 volts

Response Time: Typical response to a step change in dissolved

oxygen
at 20°C is 90% of the change in 30 seconds.

17

APPENDIX A

The 5905 and 5010 probes come in several versions, designed to
fit different bottle sizes.

5905
5010
200-BOD
Pro-BOD

5905 - J
5010 - J

5905 - K
5010 - K

5905 - L
5010 - L

5905 - W
5010 - W

5° taper per side to fit U.S. Standard BOD
bottles.

Includes an adapter to fit 5° taper per side
smaller bottles with built - in overflow
funnels.

Includes a

Includes a

19 funnel.

24 funnel.

6″ long probe for use with wine bottles.

The 5010 probe will only work with the Model 5000 and 5100
Instruments. A 5905 probe will also work on these instruments
by using a 5011 plug adapter. A 200-BOD will only work with a
DO200 Instrument. The Pro-BOD will only work with the Pro20
and ProPlus Instruments.

18

Pro-BOD

N/A

605306

059895

115776

110592

115777

N/A

073035

N/A

200-BOD

N / A

605306

059895

609204

110592

609210

N / A

073035

073047

5010-W

059880

N / A

059950

110593

110592

115011

N / A

N / A

N / A

5010-L

059880

N / A

059902

115904

110594

115011

059911

N / A

N / A

5010-K

059880

N / A

059902

115904

110594

115011

059933

N / A

N / A

5010-J

059880

N / A

059902

115904

110592

115011

059929

N / A

N / A

5010

059880

N / A

059895

110590

110592

115011

N / A

N / A

073035

N / A

073047

5905-W

059880

N / A

059950

110593

110592

110591

APPENDIX B

N / A

5905-L

059880

N / A

059902

115904

110594

110591

059911

073035

073047

5905-K

059880

N / A

059902

115904

110594

110591

059933

See dealer

See dealer

Accessories and Replacement Parts by Item Number

5905-J

059880

N / A

059902

115904

110592

110591

059929

073035

073047

5905

059880

N / A

059895

110590

110592

110591

N / A

073035

073047

Description

5906 Membrane Kit

5908 Membrane Kit

Stir Paddle

Probe Assembly

Motor Assembly

Housing Assembly

Funnel / Adapter

115 V Power Supply

230 V Power Supply

19

1700/1725 Brannum Lane
Yellow Springs, Ohio 45387 USA
[phone] • 800 897-4151 (US) A59882L
Fax [phone] May 09
[e-mail] • www.ysi.com

© 1997 YSI Incorporated

059882

20