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DATAPLATE®

Digital Hot Plate/StirrerOPERATING MANUAL

Series 720

720-0025 • 3/28/00

BARNSTEAD|THERMOLYNE CORPORATION

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Table of Contents

Introduction ........................................................................................................................................................ 3Important Information .................................................................................................................................. 3

Safety Information .............................................................................................................................................. 4Alert Signals ................................................................................................................................................ 4Warnings ...................................................................................................................................................... 4Cautions ...................................................................................................................................................... 5

General Description ........................................................................................................................................... 7Heater .......................................................................................................................................................... 7Stirrer ........................................................................................................................................................... 7Timer ............................................................................................................................................................ 8Other Instruments in the 700 Series ............................................................................................................ 8

Operation ......................................................................................................................................................... 10Front and Rear Panels .............................................................................................................................. 10Set-Up ....................................................................................................................................................... 12Setting Temperature, Ramp Rate, Stirrer Speed and Timer ...................................................................... 13Display Functions ...................................................................................................................................... 14Setting Temperature, Ramp Rate, Stir Speed & Timer .............................................................................. 16Auto-Off Function....................................................................................................................................... 19Other Operations ....................................................................................................................................... 19

Maintenance..................................................................................................................................................... 20Temperature Calibration ............................................................................................................................ 20Helpful Hints .............................................................................................................................................. 21

Troubleshooting ............................................................................................................................................... 22

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Introduction

Congratulations on your purchase of a DigitalHot Plate/Stirrer. This unit is designed to doa number of jobs within your laboratory.Please read the instructions carefully toinsure that you receive the maximum benefitfrom it. Also, be sure to fill out and return theenclosed warranty registration card. Wewould like to receive the informationrequested, and it will help us assure you ofproper warranty coverage.

Important InformationThis manual contains important operatingand safety information. You must carefullyread and understand the contents of thismanual prior to using this equipment.

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Your Dataplate Digital Hot Plate/Stirrer has beendesigned with function, reliability, and safety inmind. It is the user's responsibility to install it inconformance with local electrical codes. For safeoperation, please pay attention to the alert boxesthroughout the manual.

Please note the following WARNINGS:

WarningsThis warning is presented for compliance withCalifornia Proposition 65 and other regulatoryagencies and only applies to the insulation in thisproduct. This product contains refractory ceramic,refractory ceramic fiber or fiberglass insulation,which can produce respirable dust or fibers duringdisassembly. Dust or fibers can cause irritationand can aggravate preexisting respiratorydiseases. Refractory ceramic and refractoryceramic fibers (after reaching 1000°C) containcrystalline silica, which can cause lung damage(silicosis). The International Agency for Researchon Cancer (IARC) has classified refractoryceramic fiber and fiberglass as possiblycarcinogenic (Group 2B), and crystalline silica ascarcinogenic to humans (Group 1).

The insulating materials can be located in thedoor, the hearth collar, in the chamber of theproduct or under the hot plate top. Testsperformed by the manufacturer indicate that thereis no risk of exposure to dust or respirable fibersresulting from operation of this product undernormal conditions. However, there may be a riskof exposure to respirable dust or fibers whenrepairing or maintaining the insulating materials,or when otherwise disturbing them in a mannerwhich causes release of dust or fibers. By usingproper handling procedures and protective

Safety Information

WarningWarnings alert you to a possibil-ity of personal injury.

CautionCautions alert you to a possibil-ity of damage to the equipment.

NoteNotes alert you to pertinentfacts and conditions.

Alert Signals

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SAFETY INFORMATION

equipment you can work safely with theseinsulating materials and minimize anyexposure. Refer to the appropriate MaterialSafety Data Sheets (MSDS) for informationregarding proper handling andrecommended protective equipment. Foradditional MSDS copies, or additionalinformation concerning the handling ofrefractory ceramic products, please contactthe Customer Service Department atBarnstead|Thermolyne Corporation at 1-800-553-0039.

Cautions

Heater Plate SurfaceDATAPLATE Hot Plate/Stirrer Series 720 iscapable of temperatures in excess of 370°C,± tolerance, at the plate surface. Touchingthe heated surface will cause severe burns.USE EXTREME CAUTION AT ALL TIMES.Never leave your DATAPLATE Hot Plate/Stirrer accessible to others while it is hot.Although the unit is equipped with a "HotWarning" indicator on the front panel, do notrely on this alone. Never touch the heatingsurface unless you are absolutely sure that itis cool.

Temperature ProbeWhen attempting to control PROBETEMPERATURE, it is necessary to plug in atemperature probe and to place it in thesample AT ALL TIMES. If the probe is notplaced into the sample, the unit will not beable to sense the rising temperature of the

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SAFETY INFORMATION

sample as heat is applied. This will result indriving the heater to its maximum and couldresult in ruining the sample.

An optional temperature probe is made of 316stainless steel is available. The stainless steelprobe can be attacked by some chemicals.Coating the probe with Teflon spray or Teflontubing may help. However, this coating may slowthe probe response time and result intemperature errors until it equilibrates. Alsoavailable is our borosilicate glass temperatureprobe #710-0203 for use with very aggressivechemicals. Temperature probes are not includedwith unit.

ElectricalThe DATAPLATE Hot Plate/Stirrer 720 Series ismade in models that operate at 100, 120 and 240volts AC. Be certain that your voltage matchesthe unit that you receive. Check the plate on thebottom for the voltage setting on your unit. Takethe normal care and precaution one would usewith any electrical appliance. Be very careful tokeep the AC line cord away from the hot plate.

The DATAPLATE Hot Plate/Stirrer Series 720 isa programmable, general purpose, digitallaboratory hot plate with stirrer. The seriesincludes the Model 721, single position stirrer, theModel 725, 5-position stirrer and the Model 729,9-position stirrer. All functions on the Series 720are settable from a digital front panel keyboardand display. Both the plate temperature and thestirrer speed are controllable to an accuracynever before offered in similar devices.

CautionTouching the heated surface willcause severe burns. USEEXTREME CAUTION AT ALLTIMES.

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General Description

HeaterEither the plate surface temperature or the actualsample temperature may be set by the user. Asensor in the plate is used to monitor surfacetemperature, or, alternatively, a temperatureprobe may be connected to the rear of the unitand inserted into the sample. An optional 100Ω3-wire, Platinum RTD temperature probe isavailable with a 6" stainless steel or glass jacket.When a temperature is set by the user, power isapplied to the heater to precisely control thetemperature at the plate surface or at the sample,as directed.

An optional "ramp value" may be entered into theunit which causes the temperature to approachthe target value at a controlled rate oftemperature change. Temperature may bedisplayed in either °C or °F as set by a rear panelswitch.

StirrerThe stirrer is a motor-driven magnet which, in themodel 721, revolves directly under the center ofthe heater plate. The Model 725 has five motorswith one placed in the center and one at eachcorner of the plate. The Model 729 has ninestirrer motors placed in three rows of three each.It is common practice, when heating solutions, tospin a "stir bar" (Teflon-coated bar magnet) whichis placed in the solution. This assures a moreuniform temperature throughout the solution.

The stirrer speed is set from the front panelkeyboard.

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GENERAL DESCRIPTION

TimerAll Series 720 units have built-in timers. Thetimer counts down in hours, minutes andseconds, sounding an alarm when it reacheszero. The timer may be used independently ofthe heater and stirrer or may be used inconjunction with the "Auto Off" function to shut offboth the heater and stirrer after a preset length oftime.

Other Instruments

Model 730 Programmable Hot Plate/Stir-

rerThe Series 730, available in 1,5, and 9 positionstirrer models, includes extra features notavailable in the 720 series. In addition to all of thefunctions found on the 720, the Model 730contains a program memory of 75 steps. Theuser may enter a sequence of temperatures, stirspeeds and time delays which may the be run bypressing a single button. The program memory isbattery-powered so the program remains in theunit indefinitely when it is turned off.The 730 series also has an infrared remotecontrol sensor circuit. The optional Model 745remote control keyboard can be used to operatethe various models from distances of up to 15feet. This typically is used in situations where theunit is kept under a fume hood or is otherwiseinaccessible.

Model 740 Multi-ControllerBoth Series 720 and 730 DATAPLATE Hot Plate/Stirrers may be operated as remote stations tothe Model 740 DATAPLATE Multi-Controller.

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GENERAL DESCRIPTION

The Multi-Controller connects to the units througha small cable, and is capable of controlling up to8 units at a time. The Multi-Controller provides anumber of enhancements, including 0.1 degreetemperature resolution, larger program memory,real-time clock and printer interface.

When connected to the Multi-Controller, frontpanel controls on both Series 720 and 730 HotPlate/Stirrers remain operational. Also availablefor use with the Model 740 Multi-Controller is theSeries 710 Hot Plate/ Stirrer which is the sameunit as the Series 720 but has no front panelcontrols. It is designed to be operated remotelyfrom the Model 740 Multi-controller.

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Operation

Front Panel

Front And Rear Panels

Front PanelThe front panel of the DATAPLATE 720 Series hasa digital keyboard display for monitoring andcontrolling hot plate functions. The ON/Off switch islocated on the right side of the front panel. Whenthe unit is on, the display located on the left side ofthe unit will be lighted.

The display is a four-digit vacuum fluorescent typewith a colon between the middle two digits. It isused to display the temperature, stirrer speed andtimer value. The keyboard has 12 pushbutton keysand is used both for selecting the display functionand for entering numerical values for thetemperature, stirrer speed andtimer.

A number of LED indicator lamps also are locatedon the front panel. These will be explained in a latersection.

A thin plastic membrane which fits over the frontpanel is supplied with the unit to protect it fromdust, dirt and possible chemical spills. Thekeyboard may be operated with the membrane inplace. Replacement membranes are available.

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OPERATION

Rear Panel

Rear PanelThe AC power connector jack and fuse holdercombination is located on the left side of the rearpanel. The °C/°F display switch is to its right,followed by the l/O port, the remote temperaturesensor jack and the four temperature calibrationpots on the right side of the panel.

The AC power jack is a three-prong, male plugcombined with a dual, snap-in fuse holder. The typeof fuse used in the unit is embossed on the front ofthe holder. Both neutral and high lines are fused.

The °C/°F display is controlled by the position of theslide switch to the right of the power jack. The frontpanel display will reflect the temperature units bydisplaying a °C or °F after the temperature readout.

The I/O port will, when used with the proper cable,allow for remote control of the unit by the Model740 multicontroller.

The remote temperature sensor input is a 5-pin DINjack which is used with a three-wire, Platinum RTDtemperature probe.

The two calibration potentiometers on the left arefor calibrating the remote temperature sensor, thetwo on the right are for calibrating the hot platetemperature readout.

CautionIf the fuse blows repeatedly,contact the distributor.

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OPERATION

Set-Up1. Place the unit on a level, dry bench or

surface.

2. Plug the unit into a properly grounded,three wire outlet of proper voltage.

3. Plug the temperature probe (if used) intothe jack on the rear of the unit.

4. Place the sample on the heater plateand put the temperature probe and stirbar into the sample. Be sure the vesselis centered and that the stir bar is cen-tered in the vessel. Also be sure that thetemperature probe will not obstruct therotation of the stir bar.

Try to match the stir bar to the sample andcontainer size to optimize mixing. Generally,larger stir bars are needed to mix more viscoussamples. However, two-inch long bars match themagnet in the stirrer best.

5. Turn the unit ON by the rocker switch onthe front panel. Note that the unit willbeep once and will be in the PLATETEMPERATURE mode. At this point youcan change the display modes by touch-ing PLATE TEMP, PROBE TEMP, STIR-RER RPM, TIMER HR:MIN, or TIMERMIN:SEC. Note that the display indica-tions will change as you touch the differ-ent keys.

6. Set the target temperature, stirrerspeed, timer and ramp rate according tothe instructions that follow.

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OPERATION

1

PLATETEMP

2

PROBETEMP

Display FunctionsThe display can be instructed to show any of sixdifferent functions. The function currently beingdisplayed is indicated by a small LED lamplocated above the corresponding display functionkey (top row of keys).

HeaterPress this key to display the temperature of theheater plate surface. The display will be in °C or°F as selected by the rear panel C/F switch, andindicated by a "C" or "F" on the right portion of

the display. If a target plate temperature hasbeen set into the unit, the display will toggle atbrief intervals to display the target temperature.The PLATE TARGET lamp will turn on duringthe time the target temperature is shown. The redPLATE HOT lamp located to the right and belowthe display, will blink if the plate temperature isabove 50 °C (122 °F) as a safety reminder.

Press this key to display the temperaturemeasured by the probe. The display will be in °Cor °F as selected by the rear panel C/F switchand indicated as above. IF the probe is notplugged in, the probe temperature will read 0°Cor 32°F. If a target probe temperature has beenset, the display will toggle at brief intervals todisplay the target temperature. The PROBETARGET lamp will turn on during the time thatthe target temperature is shown. If the probe isunplugged the display will show all dashes.Dashes will also appear if the temperature is outof range (0 - 400°C).

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4

TIMERHR:MIN

3

STIRRERRPM

OPERATION

5

TIMERMIN:SEC

6

RAMP°/HR

Stirrer SpeedPress this key to display the speed of the stirrer.The speed is shown to the nearest ten RPM. Onmulti-position stirrer models the speed is takenfrom the center stirrer position.

TimerPress this key to display the hours and minutesleft on the timer.

Press this key to display the minutes andseconds left on the timer.

RampPress this key to display the current ramp value.The value is displayed in °C/HR or °F/HR asselected by the rear panel C/F switch. If rampingis disabled, the display will show "OFF".

Setting Temperature, RampRate, Stirrer Speed and TimerThe heater, stirrer and timer may all be setthrough the use of the SET/ENTER key. Thesettable functions are listed below, followed by anexplanation of how values are entered for thosefunctions.

HeaterThe heater may be set to control either the platesurface or the sample itself. This is done byentering a "target" temperature from the front

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OPERATION

Enter

SET

1

PLATETEMP

panel keyboard. The control electronics in the hotplate will automatically apply power to the heaterplate to reach the desired target temperature.

The user may enter either a target platetemperature or a target probe temperature. Onlyone target temperature is allowed at a time.Setting a target plate temperature erases anytarget probe temperature that may have been setpreviously and vice versa.

Target temperatures may be set anywhere in therange of 0 to 370°C (32 to 698°F).

To set a target plate temperature, press the SETkey followed by the PLATE TEMP key; enter thetemperature value desired and press the ENTERkey. The target temperature is entered in °C or°F depending on the current mode as set by theC/F switch on the rear panel. Setting a targettemperature enables the heater plate. Thismeans that the heater plate will turn on asnecessary to heat the plate surface to the targettemperature. If the target is below the actualplate temperature, the heater plate will not turnon until the plate cools to near the targettemperature.

To set a target probe temperature, press the SETkey followed by the PROBE TEMP key;enter the temperature value desired and pressthe ENTER key. The target temperature isentered in °C or °F depending on the currentmode as above. Setting the targettemperature enables the heater plate. The heaterplate will turn on as necessary to heatthe sample until the sample probe reaches thetarget temperature. If the probe is unplugged,heating power will be disabled until the probe isplugged into the rear connector.

Enter

SET

2

PROBETEMP

CautionBe sure the temperature probeis in the sample solution andplugged into the rear panelwhen heating. Failure to do socould damage your samplebecause the hot plate willdrive to maximum seeking atemperature it cannot find.

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OPERATION

Enter

SET

3

STIRRERRPM

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STIRREROFF

To disable the heater plate and erase the plate orprobe target temperature, press the HEATER OFFkey.

StirrerThe stirrer speed is set in a similar manner to thetarget temperature above except that the

STIRRER RPM key is pressed after the SET key.The target stirrer speed is rounded internallyto a multiple of ten RPM. The stirrer may be set toany speed within the range 0 to 1500 RPM.However, the majority of the units are specified tooperate from 100 to 1200 RPM.

To turn off the stirrer, press the STIRRER OFF key.This is the same as setting the stirrer speed to zero.

TimerThe timer counts in hours, minutes and seconds.However, the user may only display or set thehours and minutes or the minutes and seconds at agiven time. Setting the hours and minutes also setsthe seconds to zero. Setting the minutes andseconds sets the hours to zero.

The timer may be set to any count up to 99:99,however, when the minutes or seconds roll overthey will be set to 59 as on a clock. For example, 80seconds may be set into the timer either as 1:20 oras :80 minutes/seconds. When the timer reacheszero it will alarm with three audible chirps.

To set the timer in hours and minutes, press SETfollowed by TIMER HR:MIN. The seconds will beset to zero. Timing starts exactly when the ENTERkey is pressed.

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HEATEROFF

Enter

SET

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TIMERHR:MIN

NoteAluminum top, 10" x 10"Digital Hot Plate/Stirrersoperate from 100 to 800RPM.

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OPERATION

To set the timer in minutes and seconds, pressSET followed by TIMER MIN:SEC. The hours willbe set to zero. Timing starts exactly when theENTER key is pressed.

RampThe ramp setting controls the rate at which thetemperature approaches the target temperature.The ramp values may be set within the range of0 to 555°C/HR or 0 to 999°F/HR. The unit canramp up or down depending on the targettemperature. A target temperature above thesample temperature will make the unit ramp upat the specified rate. Likewise, a targettemperature below the sample temperature willmake the unit ramp down at the specified rate.The thermal characteristics of the sample andhot plate determine the maximum rate at whichthe temperature can ramp toward the targetsetting. If the ramp setting is higher than this rateit can not be attained.

To set the temperature ramp, press the SET keyfollowed by the RAMP

o/HR key.

Entering ValuesTo set a value into the heater, stirrer, timer orramp, first the SET function is selected, anumerical value is entered, and then the ENTERkey is depressed.

As described previously, the SET function isselected by pressing the SET key followed by thekey of the function desired . When the SET key ispressed, the display shows all dashes withvertical doglegs (L L L L). At this time only the sixsettable function keys and the CLEAR key areactive. Pressing the CLEAR key will erase SET

Enter

SET

5

TIMERMIN: SEC

6

RAMP0/HR

Enter

SET

Enter

SET XXX

CautionBe sure to enter a targettemperature before entering aramp rate. The hot plate willdrive to maximum and maydamage the unit if no targetvalue has been entered.

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OPERATION

and return the unit to the function that was beingdisplayed before SET was pressed. Pressing oneof the function keys will cause the display toshow all zeros. At this point, the keys becomenumeric and the value may be entered.

Key in the value you wish to set, one digit at atime, up to four digits. The digits enter the displayfrom the right, calculator-style.

If you make a mistake, press the CLEAR key andthe display will return to all zeros. If you wishto exit from the SET function without actuallyentering a value, press the CLEAR key againwhile the display shows all zeros.

After keying in the desired value, press theENTER key. The new value will be entered atthis time and the function which was just set willbe displayed. If the value entered is out of range,however, it will not be accepted, and will be heldon the display until the CLEAR key is pressed.Once the value is accepted, the keys return totheir normal functions and no longer representnumeric data.

Auto-Off and Hold FunctionsWhen the auto-off function is enabled, a time-outof the timer automatically turns off the heater andthe stirrer. This provides a convenient way topreset the length of time a sample is to beheated without the need for anyone to be presentat the end of the period.

To enable the auto-off function, press theAUTO-OFF key and the lamp under the key willturn on. To disable auto-off, press the key againand the lamp will go out.

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AUTOOFF

0 9–

CLR

Enter

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OPERATION

Other OperationsThe DATAPLATE Digital Hot Plate/Stirrer isdesigned to be used as a temperature meter andlaboratory timer, too. To use either way, followthe instructions below:

Temperature MeterTo use the DATAPLATE as a temperature meter,bring the sample to the unit and plate thetemperature probe in the solution. Then touchPROBE TEMP and the temperature will bedisplayed.

TimerTo use your DATAPLATE Digital Hot Plate/Stirreras a laboratory timer, simply touch SET, TIMERHR:MIN (or TIMER MIN:SEC), the time desired,then ENTER. As soon as the ENTER key istouched the unit will start to count down. It willbeep three times at zero.

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Maintenance

Temperature CalibrationThe temperature readouts for both the platesurface and the probe may be calibrated by theuser. Two rear panel adjustments are providedfor each temperature channel.

Probe calibration is performed using anaccessory calibration kit (part # 710-5001) whichprecisely simulates fixed temperature points. Thekit has a high temperature "dummy" probe whichwhen plugged into the probe connector presentsthe same value of resistance to the internaltemperature analyzing circuitry as the RTD probeat the temperature which is written on thecalibrator case. There is also a low temperatureplug-in which simulates the response at thetemperature called out on the calibrator case.

To calibrate the probe readout, first insert thehigh temperature "dummy" probe into thetemperature probe DIN connector located on therear panel. Then adjust the calibration potmarked PROBE HI until the front panel readoutagrees with the temperature stamped on the"dummy" probe. When the high temperature hasbeen adjusted, repeat the procedure with the lowtemperature probe module by adjusting thepotentiometer marked PROBE LO to agree withthe temperature marked on the "dummy" probe.The probe readout calibration is now complete.The calibration must be carried out in the orderspecified above (Hi temp; Low temp).

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MAINTENANCE

Helpful Hints

1. Use on a level surface when stirring,especially when stirring violently. If theunit is not level, the sample containerwill "walk", and could walk right off theplate.

2. Stirring thicker solutions may requireusing a larger stir bar. Generally, themore viscous a solution, the larger thestir bar needed. For best operationoverall, it is recommended that the stirbar match the magnet poles in thestirrer. These are 2 inches apart.

3. Targeting the temperature for the heaterplat can result in an overshoot of thetarget temperature as measured at thesample. This is especially true whenhigh ramp hating rates are used inconjunction with small liquid samples,and when target temperature is close toambient temperature.

For best results with the least overshoot, twomethods can be chosen. First, less overshootoccurs in metal sample containers, but thatdoesn't help those who use glass. Second, ifusing glass, expect a slight temperatureovershoot. If it important not to overshoot, thentarget your temperature 5°C to 10°C below thedesired temperature. When that temperature isreached, the unit will slowly ramp the finaltemperature. This will result in a very minimaltemperature overshoot. Large samples and targettemperatures over 100°C very seldom overshoot.

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Troubleshooting

PROBLEM WHAT TO DO/EXPLANATION

The sample temperature does notrise as rapidly as the programmedramp value.

The probe temperature does notdisplay 100°C or 212°C whenimmersed in boiling water.

The probe temperature readoutdoes not display 0°C or 32°F whenimmersed in an ice bath.

The sample temperature readingremains higher than the targettemperature.

The probe temperature reads 0°Cor 32°F regardless of the targetsetting.

The stir bars are turning at too lowa speed or are revolving erratically.

1. Try heating a smaller sample. Theheating capacity of theDATAPLATE Heater/Stirrer isprobably not adequate to raise thesample temperature at the pro-grammed rate.

1. If you are in a location which is1000 ft. or more above sea level,your boiling point will decrease.

2. Perform the probe calibrationprocedure given on p. 20.

1. Check the purity of the water.Dissolved substances will usuallylower the freezing point of water.

2. Perform the probe calibrationprocedure given on p. 20.

1. Check the ambient temperature.The target temperature may bebelow room temperature.

1. Check to see that the probe plug isseated tightly and making contact.If it is not making contact the read-out will default to 0°C or 32°F.

1. Check to see that the samplecontainers are centered over thestir bar motors.

2. The stir bars may not be able tokeep up with the motors due to theviscosity of the liquid sample.

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9001ISOREGISTERED

Barnstead|Thermolyne2555 Kerper Blvd.P.O. Box 797Dubuque, IA 52004-2241Phone: 319-556-2241 800-553-0039Fax: 319-589-0516E-Mail Address: mkt@barnstead.com