BARNSTEAD|THERMOLYNE CORPORATION
MIRAK™ Hot Plates,
Stirrers and
Stirring Hot Plates
OPERATION MANUAL
AND PARTS LIST
SERIES 725, 726, 727, 728, 729, 730
Model # Voltage Description
HP72620 240 7x7
HP72620-26 220-240 7x7
HP72624 100 7x7
HP72625 120 7x7
S72520 240 7x7
S72520-26 220-240 7x7
S72524 100 7x7
S72525 120 7x7
SP72720 240 7x7
SP72720-26 220-240 7x7
SP72724 100 7x7
SP72725 120 7x7
HP72930 240 12x12
HP72930-26 220-240 12x12
HP72934 100 12x12
HP72935 120 12x12
HP72935-60 120 12x12
HP72938 208 12x12
S72830 240 12x12
S72830-26 220-240 12x12
S72834 100 12x12
S72835 120 12x12
SP73030 240 12x12
SP73030-26 220-240 12x12
SP73034 100 12x12
SP73035 120 12x12
SP73035-60 120 12x12
SP73038 208 12x12
LT727X7 • 9/9 /99 Serial Number: _______________________________
IMPORTANT INFORMATION
This manual contains important operating and safety information. The user must carefully
read and understand the contents of this manual prior to the use of this equipment.
Table of Contents
Safety Information.........................................................................................................................3
Alert Boxes..................................................................................................................................3
Warnings......................................................................................................................................3
Introduction................................................................................................................... ...............5
Unpacking....................................................................................................................................5
Installation............................................................................................................................... .....7
Principles of Operation..................................................................................................................7
Operation...................................................................................................................... ...............8
Removing the Clear Plastic Cover ..............................................................................................8
The Power Switch.....................................................................................................................8
Setting the Stirring Speed.........................................................................................................8
Stirring Speed Guide................................................................................................................9
Setting the Temperature ...........................................................................................................9
Controlling Top Plate Temperature..........................................................................................10
Controlling Solution Temperature ............................................................................................1 0
Calibrating the Probe Temperature Input..................................................................................11
Using the Probe with the Temperature Display for Stirring-only Applications...............................11
To Achieve Fast Heat-up of Large Volumes..............................................................................12
Heating Small Volumes ...........................................................................................................12
Heating Metal Vessels and Sand Baths....................................................................................12
Heat-up Time Guide................................................................................................................12
Operating Specifications .............................................................................................................14
Heating Specifications............................................................................................................14
Stirring Speed Specifications..................................................................................................14
General Operating Specifications.................................................................................................15
Dimensions- 7" x 7" Models\l 2.....................................................................................................15
Dimensions- 12" x 12" Models\l 2.................................................................................................15
Electrical Ratings- 7" x 7" Models\l 2.............................................................................................1 5
Electrical Ratings- 12" x 12" Models\l 2.........................................................................................16
Temperature Range for Hot Plates and Stirring Hot Plates .........................................................16
Stirring Speed Range for Stirrers and Stirring Hot Plates............................................................16
Environmental Parameters for all units......................................................................................1 6
Maintenance and Servicing.........................................................................................................17
Replacing the Power Board.....................................................................................................17
Replacing the Logic Board......................................................................................................18
Replacing the Display Board....................................................................................................18
Replacing the Motor................................................................................................................18
Replacing the Top Plate Assembly...........................................................................................19
Set-up Procedure...................................................................................................................20
Troubleshooting Guide ...........................................................................................................21
Replacement Parts List...............................................................................................................25
Ordering Procedures ..................................................................................................................26
Warranty.....................................................................................................................................2 7
2
Safety Information
Your Thermolyne MIRAK™ stirrer, hot plate, or stirring hot plate has been designed with function,
reliability, and safety in mind. It is your responsibility to install it in conformance with local electrical codes.
Alert Signals
WARNING
Warnings alert you to a possibility of personal injury.
CAUTION
Cautions alert you to a possibility of damage to the equipment.
NOTE
Notes alert you to pertinent facts and conditions.
Warnings
WARNING
To avoid electrical shock, always:
1. Use a properly grounded electrical outlet of correct voltage and current handling capacity.
2. Disconnect from power supply before servicing.
To avoid personal injury:
1. Do not use in the presence of flammable or combustible materials; fire or explosion may result.
This device contains components which may ignite such materials.
2. Keep top surface clean. Use a non-abrasive cleaner. Alkali spills, hydrofluoric acid spills or
phosphoric acid spills may damage top and lead to thermal failure. Unplug unit and remove spills
promptly. Do not immerse unit for cleaning.
3. Replace the top immediately if damaged by etching, scratching or chipping. A damaged top can
break in use.
4. Do not remove or modify grounded power plug. Use only properly grounded outlets to avoid
shock hazard. Not rated for use in hazardous atmospheres.
5. Use caution when heating volatile materials; top surface and element can reach the “Flash Point
Temperature” of many chemicals. These hot plates and stirring hot plates are not explosion proof.
Fire or explosion may result. Unit contains components which may ignite such materials.
6. Use appropriate hand and eye protection when handling hazardous chemicals.
7. "Caution: Hot Surface. Avoid Contact." The hot plate will remain hot without any visual indication
for some time after power has been removed.
8. Do not use in highly corrosive atmospheres; corrosive fumes and spill may damage top and
internal components, creating shock hazard.
9. Refer servicing to qualified personnel.
CAUTION
Space unit 12 inches away from combustible materials under any conditions.
Gross weight of items placed on top of Hot Plates should not exceed 25 lbs. on the 7" X 7"
and 30 lbs. on the 12" X 12" models.
3
Barnstead |Thermolyne • 800-553-0039
Please note the following WARNINGS:
WARNING
This warning is presented for compliance with California Proposition 65 and other
regulatory agencies and only applies to the insulation in this product. This product
contains refractory ceramic, refractory ceramic fiber or fiberglass insulation,
which can produce respirable dust or fibers during disassembly. Dust or fibers
can cause irritation and can aggravate pre-existing respiratory diseases.
Refractory ceramic and refractory ceramic fibers (after reaching 1000°C) contain
crystalline silica, which can cause lung damage (silicosis). The International
Agency for Research on Cancer (IARC) has classified refractory ceramic fiber
and fiberglass as possible carcinogenic (Group 2B), and crystalline silica as
carcinogenic to humans (Group 1).
The insulating materials can be located in the door, the hearth collar, in the chamber of
the product or under the top plate top. Tests performed by the manufacturer indicate
that there is no risk of exposure to dust or respirable fibers resulting from operation of
this product under normal conditions. However, there may be a risk of exposure to
respirable dust or fibers when repairing or maintaining the insulating materials, or
when otherwise disturbing them in a manner which causes release of dust or fibers
therefrom. By using proper handling procedures and protective equipment you can
work safely with these insulating materials and minimize any exposure. Refer to the
appropriate Material Safety Data Sheets (MSDS) for information regarding proper
handling and recommended protective equipment. For additional MSDS copies, or
additional information concerning the handling of refractory ceramic products, please
contact the Customer Service Department at Barnstead|Thermolyne Corporation at
1-800-553-0039.
REFER SERVICING TO QUALIFIED PERSONNEL.
WARNING
4
Introduction
Please read all the information in this manual before operating the unit.
Your Thermolyne MIRAK™ hot plate, stirrer or stirring hot plate is a general purpose heating and/or stirring
plate designed for laboratory procedures requiring precise control of temperature and/or stirring speed.
Each MIRAK model includes a digital display for monitoring actual temperature or stirring speed, and the
stirring hot plate models have dual displays so temperature and stirring speed can be monitored
simultaneously. The hot plate is capable of producing accurately controlled top plate temperatures from
40°C through 540°C on all 7" x 7" models and the 208 volt and 240 volt models of the 12" x 12" hot plates.
(12" x 12" 100 volt and 120 volt models have a temperature range of 40°C to 370°C.) The temperature
may be controlled at the plate surface by an internal Type K thermocouple sensor, or the solution
temperature may be controlled by utilizing an accessory ungrounded Type K thermocouple probe. A 6" or
10" general purpose stainless steel immersion probe, or a chemical-resistant 7" solid Teflon® immersion
probe may be ordered separately. The stirrer will accurately maintain stirring speeds from 60 rpm up to
1200 rpm. On stirring hot plate models, the accessory probe may also be utilized to display the actual
temperature of heat-sensitive solutions during stirring-only functions. The 7" x 7" or 12" x 12" top plate on
the MIRAK units is solid ceramic, and is suitable for use with glass or metal vessels.
Your MIRAK hot plate, stirrer or stirring hot plate may be used for general purpose heating applications
and/or general laboratory mixing of solutions, including sample preparation, heating reagents, melting
paraffin, warming resinous chemicals, content analysis, solvent evaporations, digestions, media
preparation and sterilization, titrations, sand baths, and microscale chemistry applications.
Unpacking
Remove your MIRAK hot plate, stirrer or stirring hot plate from the carton. Inspect to ensure that the unit
has not been damaged during shipment. If the unit appears to have sustained shipping damage contact
the distributor from whom you purchased this product or Barnstead/Thermolyne Customer Service at 800553-0039. Remove the packaging from underneath the top plate by gently pulling the packaging material
toward you.
NOTE
A special 20-amp cord set is included on the CSA-approved models of
the 12" x 12" 120 volt MIRAK hot plate and stirring hot plate
(HP72935, SP73035). This 20-amp cordset can only be plugged into
a non-standard 20-amp, 120 volt receptacle. If you do not have the
appropriate receptacle, contact a qualified electrician for installation of
a 20-amp 120 volt outlet.
A 12" x 12" 120 volt MIRAK hot plate and stirring hot plate (HP7293560, SP73035-60) is available with a standard 15-amp, 120 volt cordset.
These models are not CSA-approved.
5
Barnstead |Thermolyne • 800-553-0039
20-amp, 120 volt
15-amp, 120 volt
6
Installation
WARNING
Set the unit on a flat stable surface at least 12" away from combustible materials, and plug the cordset into
a properly grounded electrical outlet of correct voltage and current handling capacity. Use your right hand
to locate the ON/OFF power switch which is on the side, near the front right corner as you face the unit.
Press the black ON/OFF power rocker switch into the ON position. The red LED display(s), and the green
power light to the left of the display(s) should illuminate. The unit is ready for operation.
Use a properly grounded electrical outlet of correct voltage and current handling capacity.
Do not remove or modify grounded power plug. Use only properly grounded outlets to avoid
shock hazard. Not rated for use in hazardous atmospheres.
Do not use in the presence of flammable or combustible materials; fire or explosion may
result. This device contains components which may ignite such materials.
Do not use in highly corrosive atmospheres; corrosive fumes and spill may damage top and
internal components, creating shock hazard.
NOTE
Some misalignment of the motor bearings in this product may have occurred during shipping.
Prior to using this product, run the stirrer at maximum speed for ten minutes to realign the
bearings.
Principles of Operation
Each MIRAK unit utilizes the latest in microprocessor technology to deliver the most reliable, accurately
controlled, ceramic top hot plate, stirrer and stirring hot plate on the market.
Your MIRAK hot plate or stirring hot plate has an electronic closed-loop feedback control which will
accurately maintain temperature setpoints from 40°C through 370°C or 540°C, depending on the model.
The top plate surface temperatures are calibrated and verified at the factory using the latest in infrared
temperature measurement. The measurements are made with an infrared camera mounted approximately
26" above the top surface of the hot plate or stirring hot plate. If the temperature measurement of the
ceramic top is made with measurement devices other than infrared, the error of the measuring technique
may be greater than the error of the unit.
The MIRAK units use a Type K thermocouple for measuring both the top plate temperature, and the
solution temperature when using the probe. Both top plate surface and probe temperature are measured
with independent analog circuits. This provides a significant increase in reliability due to the redundancy of
the circuit. Because of the dual sensors it is possible to heat certain types of metal vessels and sandbaths
on the MIRAK without damaging the ceramic top. However, we recommend that you do not control the
temperature with the probe when heating a metal vessel or a sandbath.
The electronic stirring speed control will maintain the speed setpoint when the unit is loaded at ±2 RPM as
displayed by the LED display on the unit. The motor in the MIRAK stirrers and stirring hot plates produces
maximum stirring torque under normal laboratory load conditions, and is combined with a powerful magnet
to provide exceptional magnetic coupling with a stirbar.
7
Barnstead |Thermolyne • 800-553-0039
Operation
WARNING
Removing the Clear Plastic Cover
Your MIRAK unit has a protective plastic cover over the front control panel. This plastic cover is designed
to protect the control knobs and the display panel from spills, and should remain in place when the unit is
being used. To use the knob(s) while the plastic cover is in place, spin the knob(s) from the bottom where
the knob projects below the plastic cover. This plastic cover can be easily removed for cleaning by
grasping the cover at each bottom corner and gently pulling the sides of the plastic cover away from the
case while lifting the cover toward you. To replace the cover simply slide it back onto the case.
Use caution when heating volatile materials; top surface and element can reach the “Flash
Point Temperature” of many chemicals. These hot plates and stirring hot plates are not
explosion proof. Fire or explosion may result. Unit contains components which may ignite
such materials.
Use appropriate hand and eye protection when handling hazardous chemicals.
"Caution: Hot Surface. Avoid Contact." The hot plate will remain hot without any visual
indication for some time after power has been removed.
CAUTION
To avoid damage to the top plate or heating element, always keep a vessel filled with liquid on
the top plate of a hot plate or stirring hot plate when the unit is heating or cooling.
The Power Switch
Your MIRAK unit has a separate ON/OFF power switch which is a black rocker switch located on the lower
front corner of the right side as you're facing the unit. This separate power switch allows you to turn your
MIRAK hot plate, stirrer or stirring hot plate on or off without disturbing your temperature and/or speed
setting. Your last setpoint will be held in memory even if the unit is unplugged and will reappear on the
display as soon as the unit is powered up again. Whenever the power is on, a green power light illuminates
on the front control panel.
Setting the Stirring Speed
Your MIRAK stirrer or stirring hot plate has an electronic feedback speed control which will maintain a
precise speed setpoint from 60 rpm through 1200 rpm at ±2 rpm. (Maximum speed is dependent on
viscosity of the solution.) The MIRAK stirrers and stirring hot plates are equipped with a strong magnet and
high torque motor which will draw a vortex in up to 1800 ml of water stirred in a 2 liter flask with a new 2" stir
bar.
To set the speed, spin the SPEED CONTROL knob until your desired setting is indicated on the digital
display. As you move the knob, the SET light next to the RPM display will illuminate. Turn the knob
clockwise to increase the speed or counterclockwise to decrease the speed. The unit will not start to stir
until you press the speed control knob. Once the unit begins stirring the display will register ACTUAL
speed and the SET light will no longer be illuminated. To check your setpoint, move the knob
counterclockwise one position. You will feel a click, the SET light will illuminate, and your setpoint will be
displayed again for five seconds. After five seconds the display will automatically return to indicating actual
speed and the SET light will go out. To stop the stirring action without changing your setpoint press the
knob once. To resume stirring at the set speed, press the knob again.
8
If you want to ensure that the unit will not start to stir if the knob is inadvertently pressed, turn the speed
control knob until the display indicates the word OFF.
Stirring Speed Guide
Amount of
Unit Flask Size Stirbar Size
7" x 7" MIRAK 1 liter 2" 800 ml water 1200 rpm
7" x 7" MIRAK 2 liter 2" 1800 ml water 1200 rpm
7" x 7" MIRAK 1 liter 2" 1000 ml Cooking oil 700 rpm
7" x 7" MIRAK 500 ml 2" 350 ml 30 weight
*Maximum speed obtained without the stir bar loosing coupling with the magnet.
The 12" X 12" MIRAK stirrers and stirring hot plates will produce stirring speed results similar to those
provided above for the 7" X 7" units. For speed stability and display accuracy please refer to the Operating
Specifications on page 13.
Solution Viscosity
motor oil
Maximum
Speed*
1100 rpm
Setting the Temperature
Your MIRAK hot plate or stirring hot plate has an electronic closed-loop feedback control which will
accurately maintain temperature setpoints from 40°C through 370°C or 540°C, depending on the model.
An unloaded hot plate will heat to maximum temperature in just 8 minutes. A HOT light on the front panel
will illuminate whenever the top surface temperature exceeds 50°C. The temperature may be controlled
either at the top plate by the internal Type K thermocouple sensor, or in the solution using an accessory
ungrounded Type K thermocouple probe. (A 6" or 10" stainless steel general purpose immersion probe,
or a chemical-resistant 7" Teflon® immersion probe are available through your distributor, or by contacting
Barnstead/Thermolyne, 800-553-0039). Your MIRAK hot plate, stirrer or stirring hot plate will accept any
ungrounded Type K thermocouple probe, however the accuracy of probes other than the ones we've
tested and specified may exceed the probe accuracy rating we've designated.
Your MIRAK hot plate or stirring hot plate will display the temperature in °C. The display will always indicate
'OFF' or your last setpoint, and the 'SET' light will be illuminated until you press the heat control knob to
initiate operation. Once the heat control knob has been pressed the ACTUAL temperature of the top
plate or the probe will be displayed, and the 'SET' light will no longer be illuminated. If you want to check
your setpoint, you do not have to press the knob again, simply turn the knob counterclockwise one click.
Your setpoint will be displayed for approximately five seconds until the display returns to indicating the
actual temperature.
NOTE
If you want to ensure that the unit will not heat if the knob is inadvertently pressed, turn the temperature
control knob until the display indicates the word 'OFF'.
The temperature display will not indicate a temperature less than 40°C. If the actual
temperature is less than 40°C, the word 'LO' will be indicated until the actual temperature
reaches 40°C.
9
Barnstead |Thermolyne • 800-553-0039
Controlling Top Plate Temperature
Your MIRAK hot plate or stirring hot plate will control the top plate, and the display will indicate top plate
temperature WHENEVER THE PROBE IS NOT PLUGGED IN. When the unit is displaying the top plate
temperature the word TOP on the front panel will be illuminated.
Controlling Solution Temperature
To control your solution temperature simply plug an ungrounded Type K thermocouple probe into the
probe receptacle located on the back of the unit, and place the probe in your solution. The display will
indicate the actual temperature of the solution as measured by the probe, and the word PROBE on the
front panel will be illuminated.
NOTE
The solution probe offers more exact temperature control than regulating the top plate by the internal
sensor. If you need to maintain a precise setpoint we recommend using a probe to control the solution
temperature instead of controlling the top plate temperature.
When using a probe with your MIRAK hot plate or stirring hot plate it is recommended that you use a clamp
on a support rod to hold the probe in your solution.
To ensure accurate probe readings, as much of the probe sheath as possible should be immersed in your
solution. If the probe is plugged into your hot plate or stirring hot plate while the heat control is operating
but is not in solution, the temperature display will continue to indicate an ambient temperature. Because
the set point cannot be reached the element will continue to supply heat to the top plate, and the
maximum top plate temperature of 540°C may be reached.
The top plate temperature will be higher than your solution temperature.
WARNING
If the probe is plugged into your stirring hot plate while the heat control is operating but is not
in solution, the temperature display will continue to indicate an ambient temperature.
Because the setpoint cannot be reached, the element will continue to supply heat to the top
plate, and the maximum top plate temperature of 540°C may be reached. Any type K
thermocouple probe used must be an ungrounded type.
NOTE
To obtain an accurate reading when you are using the probe and stirring your solution, make sure the
probe is immersed in the liquid and is not located in air in the center of the stirring vortex. Drafts and other
temperature fluctuations will affect temperature accuracy.
The top plate temperature will not exceed the 540°C maximum.
10
Calibrating the Probe Temperature Input
NOTE
To verify the temperature reading of the probe, insert a calibrated thermometer into a solution you are
heating on the stirring hot plate. When the thermometer reading has stabilized, record the temperature
readings given by both the thermometer and by the probe as indicated on the MIRAK display.
To calibrate the probe:
1. Unplug unit, turn unit upside down and remove screws from bottom.
2. Open unit. Locate the logic board. (See illustration of interior of unit or the exploded view). Move the
3. Replace the bottom of the unit and turn the unit over.
4. Calculate the necessary correction for the probe using the following equation:
The following procedure can be performed only on units with serial numbers greater than the
following:
7" Hot Plates .... 726931000000 7" Stirring Hot Plates ... 727931000000
12" Hot Plates ...729931000000 12" Stirring Hot Plates ... 730931000000
jumper from position J11 to position J1. For 100 and 120 volt units, you must remove jumper J3 if it
exists.
Probe Error= (displayed temperature) - (actual temperature measured by other source)
Correction= 350 - Probe Error (if the error is negative, the correction is >350)
NOTE
5. Turn the unit on. The display will show "888" and then "000". The HOT, PROBE, SET and TOP
6. Turn the heat knob clockwise until the display shows the correction calculated above. Push the heat
7. Unplug unit, turn unit upside down and remove screws from bottom. Move jumper J1 to one pin of
8. Replace the bottom of the unit.
Using the Probe with the Temperature Display for Stirring-only Applications
On the stirring hot plate model, the probe can also be utilized to monitor the actual temperature of your
solution when you want to stir the solution without heating. To use the probe without heating the solution,
turn the knob until the display indicates "OFF" and press the knob to initiate operation. The element will
not supply heat to the top plate. The display will indicate 'LO' if your solution temperature remains at less
than 40°C, or the actual temperature of your solution if it is above 40°C.
The maximum error is ±10. Thus the correction must be between 340 and 360.
LED's will be on. Push the heat knob once. The digit on the far right side will get brighter.
knob again. The SET, TOP, and PROBE LED's will go out. The correction will remain on the display.
J11. For 100 and 120 volt units, replace jumper J3 if necessary.
11
Barnstead |Thermolyne • 800-553-0039
To Achieve Fast Heat-up of Large Volumes
With a Probe When heating large volumes of solution preheat the top plate at maximum temperature to
allow the plate to heat the solution quickly before plugging your probe in to the probe receptacle in the
back of the unit. As the top plate heats, monitor your solution temperature with a standard laboratory
thermometer until your solution is approximately 15 degrees below your desired setpoint. Now plug your
probe in to the unit, change the setpoint to your desired solution temperature, and place the probe in
your solution.
Without a Probe If you are heating larger volumes and do not intend to use the probe to maintain a
precise solution temperature, faster heating can be achieved by turning the heat control knob to maximum
temperature until the solution starts to heat, and then turning the setpoint back to your desired top plate
temperature.
NOTE
Heating Small Volumes
To heat small volumes quickly it should not be necessary to preheat the solution at a higher temperature.
By not preheating small volumes you avoid the potential for the temperature to overshoot your desired
setpoint. If you plan to control the solution temperature of a small volume sample with the probe, initiate
heating with the probe in the solution; no preheating should be required.
If you allow the top plate to reach the maximum temperature of 540°C while preheating and
then turn the control down to a setpoint less than 200°C, the temperature of the top will drop
rapidly to 200°C. Because of the natural cooling characteristics of ceramic, the temperature of
the top will drop much more gradually after the top plate temperature reaches 200°C.
Heating Metal Vessels and Sand Baths
Metal vessels and sand baths cannot be heated on most solid ceramic tops because of the tendency for
the metal and the sand to reflect heat back into the top, eventually exceeding the maximum temperature
rating for a ceramic top, which causes it to break. Because the advanced electronic control in the MIRAK is
capable of precisely regulating the top plate temperature, metal vessels and sand baths may be heated
safely without the danger of the ceramic top breaking.
When heating metal vessels and sand baths however, we recommend that you DO NOT use the probe to
control the temperature. Because of the heating and cooling properties of metal and sand, the sample
temperatures fluctuate, which will result in unstable top plate temperatures. We achieved better results
controlling the top plate temperature, which allowed us to maintain a constant level of heat to the sand
bath or metal vessel. The top plate setpoint should be set approximately 100° above the temperature
required for your sample, and the sample temperature may be monitored with a standard laboratory
thermometer.
Heat-up Time Guide
Temperature
Unit
7" x 7" MIRAK 540°C 1 liter 1000 ml (water) 17 min.
7" x 7" MIRAK 540°C 2 liter 1800 ml (water) 19 min.
7" x 7" MIRAK 540°C 4 liter 4000 ml (water) 25 min.
12" x 12" 120 volt MIRAK 370°C 1 liter 1000 ml (water) 26 min.
12" x 12" 120 volt MIRAK 370°C 2 liter 1800 ml (water) 32 min.
12" x 12" 120 volt MIRAK 370°C 4 liter 4000 ml (water) 46 min.
Setpoint Flask Size
Amount of
Solution
Time to Vigorous
Boil
12
12" x 12" 240 volt MIRAK 540°C 1 liter 1000 ml (water) 17 min.
12" x 12" 240 volt MIRAK 540°C 2 liter 1800 ml (water) 21 min.
12" x 12" 240 volt MIRAK 540°C 4 liter 4000 ml (water) 25 min.
Variability in heat-up times will be observed with different types of containers due to container shape and
the thickness of the container wall. For temperature accuracy and stability information please refer to the
Operating Specifications on page 13.
13
Barnstead |Thermolyne • 800-553-0039
Operating Specifications
Top Plate Surface............................................................................................Solid Ceramic
Heating Specifications
Temperature range
All 7" x 7" models and the 208 and 240 volt models of the 12" x 12" models.
40°C to 540°C
100 and 120 volt 12" x 12" models.
Heat-up time to maximum temperature (unloaded top plate). 8 minutes
Temperature stability at the center of the top plate surface (@ 70°C). ± 2.0°C
Stability of the solution temperature (400 ml of water in a 1000 ml glass flask).
Controlled by the top plate at 70°C setpoint (solution maintained at
30°C).
Controlled by the Barnstead|Thermolyne recommended immersion
probe at 70°C setpoint (solution maintained at 70°C).
Accuracy of the temperature display vs the actual temperature at the center of
the top plate (setpoint 70°C). (Top plate temperature was verified with an
infrared camera mounted approx. 26" above the center of the top plate surface;
temperature accuracy at the edges of the top plate may vary from the stated
accuracy.)
Accuracy of the temperature display vs the actual solution temperature as
measured by the stainless steel or Teflon® immersion probe (setpoint 70°C).
40°C to 370°C
± 1.0°C
± 1.0°C
± 4.0°C
± 2.0°C
Stirring Speed Specifications
Speed Range 60 to 1200 RPM
(Maximum speed is dependent on the viscosity of the solution)
Stability of the stirring speed setpoint (600 ml of water in a 1000 ml glass flask) ± 2.0 RPM
Accuracy of the speed display with the actual stirring speed ± 2.0 RPM
Max. Recommended
Top Plate Size
7" x 7" 4 liters 25 lbs
12" x 12" 6 liters 30 lbs
Flask Size Max. Weight on Top Plate
14
General Operating Specifications
Dimensions- 7" x 7" Models
Model Numbers HP72620
HP72620-26
HP72624
HP72625
Overall Width 8.250 (20.96) 8.250 (20.96) 8.250 (20.96)
Overall Height 5.750 (14.61) 5.750 (14.61) 5.50 (13.97)
Overall Depth 12.250 (31.12) 12.250 (31.12) 12.250 (31.12)
Top Plate Width 7.375 (18.73) 7.375 (18.73) 7.375 (18.73)
Top Plate Height — — —
Top Plate Depth 7.375 (18.73) 7.375 (18.73) 7.375 (18.73)
Weight lbs. (kg) 8.44 (3.81) 10.33 (4.67) 9.25 (4.20)
Dimensions- 12" x 12" Models
Model Numbers HP72930
HP72930-26
HP72934
HP72935
HP72935-60
HP72938
Overall Width 13.500 (34.29) 13.500 (34.29) 13.500 (34.29)
Overall Height 6.750 (17.15) 6.750 (17.15) 6.438 (16.35)
Overall Depth 16.625 (42.23) 16.625 (42.23) 16.625 (42.23)
Top Plate Width 12.375 (31.43) 12.375 (31.43) 12.375 (31.43)
Top Plate Height — — —
Top Plate Depth 12.375 (31.43) 12.375 (31.43) 12.375 (31.43)
Weight lbs. (kg) 18.10 (8.21) 21.28 (9.65) 17.68 (8.02)
SP72720
SP72720-26
SP72724
SP72725
SP73030
SP73030-26
SP73034
SP73035
SP73035-60
SP73038
S72520
S72520-26
S72524
S72525
S72830
S72830-26
S72834
S72835
Electrical Ratings- 7" x 7" Models
Model No. Volts Amps Watts Freq. Phase
HP72620 240 4.6 1100 50/60 1
HP72620-26 23 0 4.6 1100 50/60 1
HP72624 100 11.0 1100 50/60 1
HP72625 120 9.2 1100 50/60 1
S72520 240 0.14 19.4 50/60 1
S72520-26 23 0 0.14 19.4 50/60 1
S72524 100 0.28 16.5 50/60 1
S72525 120 0.31 18.8 50/60 1
SP72720 2 40 4.7 1119 50/60 1
SP72720-26 230 4.7 1119 50/60 1
SP72724 1 00 11.3 1117 50/60 1
SP72725 1 20 9.5 1119 50/60 1
15
Barnstead |Thermolyne • 800-553-0039
Electrical Ratings- 12" x 12" Models
Model No. Volts Amps Watts Freq. Phase
HP72930 220-240 12 3100 50/60 1
HP72930-26 220-240 12 3100 50/60 1
HP72934 100 16.5 1650 50/60 1
HP72935 120 13.5 1620 50/60 1
HP72935-60 12 0 13.5 1620 50/60 1
HP72938 208 13.9 2900 50/60 1
S72830 220-240 0.22 3 0 50/60 1
S72830-26 220-240 0.22 3 0 50/60 1
S72834 100 0.32 21 50/60 1
S72835 120 0.33 22 50/60 1
SP73030 220-240 12 3130 50/60 1
SP73030-26 220-240 12 3130 50/60 1
SP73034 1 00 16.8 1671 50/60 1
SP73035 1 20 13.8 1642 50/60 1
SP73035-60 120 13.8 1642 50/60 1
SP73038 2 08 14.1 2926 50/60 1
Temperature Range for Hot Plates and Stirring Hot Plates
104°F - 1004°F (40°C - 540°C)
Exception: 100V & 120V 12"x 12" models — maximum temperature 698°F (370°C)
Stirring Speed Range for Stirrers and Stirring Hot Plates
60 - 1200 rpm
Environmental Parameters for all units
Ambient Temperature: 17°C - 27°C (63°F - 81°F) (Exception: stirrers. See Note.)
Relative Humidity: 20% - 80% (non-condensing)
NOTE
7" x 7" and 12" x 12"
cold room at -4°C
stirrers
are suitable for use in a 37°C non-condensing incubator or in a
16
Maintenance and Servicing
WARNING
Replacing the Power Board
1. Unplug unit, turn unit upside down and remove screws from bottom.
2. Open unit. Locate power board at the back of the unit.
3. Note the position and color of wires and cable connected to the board.
4. Remove the wires and nuts.
5. Replace board and reconnect wires and cable as noted in step 3.
6. Replace the bottom and secure it with screws.
Disconnect from power supply before servicing.
Keep top surface clean. Use a non-abrasive cleaner. Alkali spills, hydrofluoric acid spills or
phosphoric acid spills may damage top and lead to thermal failure. Unplug unit and remove
spills promptly. Do not immerse unit for cleaning.
Replace the top immediately if damaged by etching, scratching or chipping. A damaged top
can break in use.
Refer servicing to qualified personnel.
Power board for hot plate detailing correct placement of wires and cables.
Power board for stirring hot plate detailing correct placement of wires and cables.
17
Barnstead |Thermolyne • 800-553-0039
Power board for stirrer detailing correct placement of wires and cables.
Replacing the Logic Board
1. Unplug unit, turn unit upside down and remove
screws from bottom.
2. Open unit. Locate logic board in the center of the
unit.
3. Note the position and color of wires and cables
connected to the board.
4. Remove the wires, cables and the 2 nuts on the
mounting bracket.
5. Replace board and mount on bracket, adjusting the
encoder wheel so that it freely rotates through the
black slot (optical pickup) on the logic board. The
black slot on the logic board should project no
further than the holes in the outer perimeter of the
encoder wheel.
6. Reconnect wires and cables as noted in step 3.
7. Proceed to Set-up Procedure.
Replacing the Display Board
1. Unplug unit, turn unit upside down and remove screws from bottom.
2. Open unit. Locate display board behind the front panel of the unit.
3. Note the position of the blue stripe running along the bottom of the cable connected to the board.
4. Disconnect the cable from the board.
5. Loosen the nuts and remove board from front panel.
6. Replace board, reconnecting cable as noted in step 3.
important for proper functioning.
7. Replace the bottom and secure it with screws.
Correct positioning of blue stripe on cable is
Replacing the Motor
1. Unplug unit, turn unit upside down and remove screws from bottom.
2. Open unit. Note position and color of wires and cables connected to the logic and display boards.
3. Remove logic board as described above.
4. Remove the wires and cable from the power board. (It is not necessary to remove the power board
from the metal plate it is mounted to.)
5. Remove the display board as described above.
6. Remove encoder wheel from motor.
18
7. Remove the screws holding the top plate onto the case. (4 screws on 7" x 7" models, 6 screws on
12" x 12" models.) Remove the clamp holding the element lead down.
8. Flip top plate over.
9. Note the distance of the magnet assembly from the baffle plate.
10. Remove the magnet assembly.
11. Remove the two screws holding the motor and replace the motor.
12. Replace the magnet assembly.
13. Flip plate over, making sure thermocouple wire comes through the plate. Reinsert screws and
tighten. (
14. Replace encoder wheel. This will need adjusting in the next step.
15. Replace logic board. Adjust encoder wheel so that it freely rotates through slot (optical pickup) on
logic board. The black slot on the logic board should project no further than the holes in the outer
perimeter of the encoder wheel.
16. Reconnect wires as noted in step 2.
17. Replace the display board and reconnect wires as noted in step 2.
18. Replace bottom and secure with screws.
Stirrers
do not have thermocouple wires.)
Replacing the Top Plate Assembly
1. Unplug unit, turn unit upside down and remove screws from bottom.
2. Open unit. Note position and color of wires and cables connected to all three boards.
3. Remove logic board as described above.
4. Remove wires and cables from the power and display boards.
5. Remove the screws holding the metal plate onto the case. (4 screws on 7" x 7" models, 6 screws on
12" x 12" models.)
6. Remove metal plate and then unscrew top plate assembly.
7. Replace top plate assembly and reattach top plate assembly to the case.
8. Replace metal plate, making sure thermocouple and element wires come through metal plate. Then
insert screws and tighten.
9. Replace logic board and mount on bracket. Adjust encoder wheel so that it freely rotates through slot
(optical pickup) on logic board. The black slot on the logic board should project no further than the
holes in the outer perimeter of the encoder wheel.
10. Reconnect wires and cables to all three boards as noted in step 2.
11 . Proceed to Set-up Procedure.
NOTE
The set-up procedure should be followed whenever the top plate assembly or the logic board
is replaced in your MIRAK hot plate or stirring hot plate. The set-up procedure is not
necessary when replacing the top plate or the logic board in the stirrers.
19
Barnstead |Thermolyne • 800-553-0039
Logic Printed Circuit Board
Set-up Procedure
1. Place a 500 ml flask with 300 ml of water on the top plate. Place a standard laboratory thermometer
(do not use the probe for this procedure) 1/2" above the bottom of the flask.
2. Turn the unit on and set the temperature at 70°C. Allow the unit to operate at this temperature for five
hours.
3. At the end of five hours, note the temperature measurement on the thermometer. (Ideally, the
thermometer should read between 41°C and 47°C.) Subtract 44 degrees from the thermometer
reading. (If your thermometer reading is greater than 44°C, your difference will be a negative
number.) Record this difference; you may need to refer to it in step #9. If the difference is zero ±3
your unit is within tolerance and you do not need to continue. If your difference exceeds zero ±3
(i.e., if it is ±4, ±5, ±6, etc.) continue with steps 4 through 13. If this difference is greater than ±20,
return the unit to Barnstead/Thermolyne for evaluation.
4. Turn the unit off, unplug the cordset from the power source, and allow the top plate to cool.
5. Once the top plate is cool, turn the unit over and remove the bottom cover. If your unit is a stirring hot
plate you should also unscrew the logic board bracket from the metal plate at this time. (Refer to the
instructions in this manual for disassembling and removing the logic board). On hot plate models you
can easily access the logic board without removing the board from it's position on the metal plate.
6. Locate the black plastic jumper on the logic board at position J11. (See the illustration on page 16).
This black plastic jumper is secured on only one pin at that location. (Do not use the jumper located
directly next to this jumper at position Jz3, which is secured by two pins). If the black plastic jumper is
not at position J11 it may be located at position J1 on your model. Remove the jumper and secure it
across both pins at position J1. If you cannot locate the jumper, contact Barnstead|Thermolyne.
7. Reattach the logic board bracket on your stirring hot plate model and realign the pickup slot with the
encoder wheel (refer to the instructions in this manual for reassembling the logic board with the
encoder wheel). Screw the bottom cover back on, plug the unit into the power source and turn the
power switch to the ON position.
NOTE
8. Push the heat knob once. The digit on the far right side of the temperature display will get brighter.
The temperature display will read 888 and then 000. The PROBE, SET, TOP and HOT lights
will all be illuminated.
This display may read something other than zero. The HOT light may be on or off which indicates
whether the number on the display is positive or negative. The number on the display is positive if
the HOT light is on. If the HOT light is off the number on the display is negative.
20
9. Refer to the difference that you recorded in step #3. If that difference was greater than +3, turn the
knob CLOCKWISE, counting each click of the knob until you have advanced the knob the same
number of positions as the difference you calculated in step #3,
click
. (The knob is detented so you can feel a click at each one degree position on the knob. Do not
turn the knob a full rotation). If the difference you recorded in step #3 was less than -3, turn the knob
COUNTERCLOCKWISE, counting each click of the knob until you have advanced the knob the
same number of positions as the difference you calculated in step #3,
10. Push the heat knob again. The PROBE, SET and TOP lights will no longer be illuminated.
11. Turn the power switch to the OFF position, unplug the cordset from the power source, and allow the
top plate to cool completely.
12. Remove the bottom cover again and move the black plastic jumper on the logic board so it is attached
to only one pin at position J1.
13. Replace the bottom again. The unit is now within tolerance and no further adjustment is necessary
until the top plate assembly or the logic board is removed again.
then turn the knob one additional
and then one additional click.
Troubleshooting Guide
Problem Solution
Unit is not operating at all. Check power.
Replace circuit breaker on power switch.
Unit is stirring or heating, but no lights are lit
on the display.
Only the power light is lit on the display. Check ribbon cable connection from the power board to the
Some digits of the display are not lit. Replace display board.
Display does not increase or decrease
when knob turned.
Speed or temperature display does not
change when knob is pushed.
Unit does not stir. Check to see if something is interfering with the motor
Unit does not heat. Check heating element. If resistance across element is greater
Display is reading erratic top plate
temperature and/or the unit takes a long
time to boil liquid without a probe.
Display is reading erratic solution
temperature.
Check cable to the display board.
logic board. It may be upside down.
Replace display board.
Check ribbon cable from knob to logic board.
Replace ribbon cable from knob to logic board.
Replace logic board.
Replace encoder switch(es) on knob(s).
Check ribbon cable from knob to logic board.
Replace logic board.
preventing it from spinning.
Replace power board or logic board.
Replace motor.
than 100 Ω, replace element.
Check connection of wires from element to power board.
Check triac located on bottom cover of unit.
Replace power board or logic board.
Replace top plate assembly.
Replace probe.
21
Barnstead |Thermolyne • 800-553-0039
Exploded View: Stirrers
22
Exploded View: Stir Plates
23
Barnstead |Thermolyne • 800-553-0039
Exploded View: Hot Plates
24
Replacement Parts List
To insure your safety and for proper operation, the ceramic top plates for hot plates and stir plates are only
sold as complete assemblies. This assembly includes the ceramic top, element, thermocouple, insulation,
baffle plate, and 2 ceramic top holders.
Key Number Part Number Unit Size Unit Voltage Item Description
1 EL727X1B 7" 120V Stir Plate or Hot Plate Top Assembly
EL727X2B 7" 220-240V Stir Plate or Hot Plate Top Assembly
EL727X3B 7" 100V Stir Plate or Hot Plate Top Assembly
EL730X1B 12" 120V Stir Plate or Hot Plate Top Assembly
EL730X2B 12" 220-240V Stir Plate or Hot Plate Top Assembly
EL730X3B 12" 100V Stir Plate or Hot Plate Top Assembly
EL730X4B 12" 208V Stir Plate or Hot Plate Top Assembly
PT467X1 7 " 100-240V Stirrer Top Plate Only
PT472X1 12" 100-240V Stirrer Top Plate Only
2 CV727X2 7" 100-240V Clear Plastic Cover
CV730X2 12" 100-240V Clear Plastic Cover
3 KB727X1A 7" & 12" 100-240V "Heat" Knob for heating units
KB727X2A 7" & 12" 100-240V "Stir" Knob for stirring units
4 MT727X1A 7" 100-120V Motor
MT727X2A 7" 220-240V Motor
MT730X1A 1 2" 100-120V Motor
MT730X2A 1 2" 208-240V Motor
5 Display Printed Circuit Boards: (Front of Unit)
PC725X4A 7" & 12" 100-240V Stirrers
PC726X1A 7" & 12" 100-240V Hot Plates
PC727X3A 7 " 100-240V Display PC Board Stir Plates
PC730X1A 12" 100-240V Display PC Board Stir Plates
6 Logic Printed Circuit Boards: (Center of Unit)
PC725X5A 7" & 12" 100-240V Stirrers
PC726X5A 7 " 100-240V Hot Plates
PC727X2A 7 " 100-240V Stir Plates
PC729X2A 12" 100-120V Hot Plates
PC730X4A 12" 100-120V Stir Plates
PC729X1A 12" 208-240V Hot Plates
PC730X2A 12" 208-240V Stir Plates
25
Barnstead |Thermolyne • 800-553-0039
7 Power Supply Printed Circuit Boards: (Back of Unit)
PC725X1A 7" & 12" 120V Stirrers
PC725X2A 7" & 12" 220-240V Stirrers
PC725X3A 7" & 12" 100V Stirrers
PC726X2A 7" & 12" 220-240V Hot Plates
PC726X3A 7" & 12" 100V Hot Plates
PC726X4A 7" & 12" 120V Hot Plates
PC727X1A 7" & 12" 120V Stir Plates
PC727X4A 7" & 12" 100V Stir Plates
PC727X5A 7" & 12" 220-240V Stir Plates
PC730X3A 12" 208V Stir Plates & Hot Plates
Not listed on Additional Replacement Parts
exploded Part Number Unit Size Unit Voltage Item Description
view SWX140 7" & 12" 100-240V Front Switch
SWX104 7" & 12" 100-240V Circuit Breaker Switch Stirrers
SWX141 7" & 12" 100-240V Circuit Breaker Switch Hot Plates and Stir
Plates.
Accessory Thermocouple Probes: (Used with all voltages)
TC727X2 7.874"
Sheath
TC732X1 6.000"
Sheath
TC732X2 10.000"
Sheath
Teflon For corrosive solutions
Stainless
Steel
Stainless
Steel
For general purpose use
For general purpose use
Ordering Procedures
Please refer to the Specification Plate for the complete model number, serial number, and series number
when requesting service, replacement parts or in any correspondence concerning this unit.
All parts listed herein may be ordered from the Barnstead|Thermolyne dealer from whom you purchased
this unit or can be obtained promptly from the factory. When service or replacement parts are needed we
ask that you check first with your dealer. If the dealer cannot handle your request, then contact our
Customer Service Department at 319-556-2241 or 800-553-0039.
Prior to returning any materials to Barnstead |Thermolyne Corp., please contact our Customer Service
Department for a “Return Goods Authorization” number (RGA). Material returned without a RGA number will
be refused.
26
Barnstead|Thermolyne
One Year Limited Warranty
Barnstead|Thermolyne Corporation warrants that if a product manufactured by
Barnstead|Thermolyne and sold by it within the continental United States or Canada proves to be
defective in material or construction, Barnstead|Thermolyne will provide you, without charge, for a
period of ninety (90) days, the labor, and a period of one (1) year, the parts, necessary to remedy any
such defect. Outside the continental United States and Canada, the warranty provides, for one (1) year,
the parts necessary to remedy any such defect. The warranty period shall commence either six (6)
months following the date the product is sold by Barnstead|Thermolyne or on the date it is purchased
by the original retail consumer, whichever date occurs first.
All warranty inspections and repairs must be performed by and parts obtained from an authorized
Barnstead|Thermolyne dealer or Barnstead|Thermolyne (at its own discretion). Heating elements,
however, because of their susceptibility to overheating and contamination, must be returned to our
factory, and if, upon inspection, it is concluded that failure is not due to excessive high temperature or
contamination, warranty replacement will be provided by Barnstead|Thermolyne. The name of the
authorized Barnstead|Thermolyne dealer nearest you may be obtained by calling 1-800-446-6060 or
writing to:
Barnstead|Thermolyne
P.O. Box 797
2555 Kerper Boulevard
Dubuque, IA 52004-0797
USA
FAX: (319) 556-0516
E-MAIL ADDRESS: mkt@barnstead.com
Barnstead|Thermolyne's sole obligation with respect to its product shall be to repair or (at its own
discretion) replace the product. Under no circumstances shall it be liable for incidental or consequential
damage.
THE WARRANTY STATED HEREIN IS THE SOLE WARRANTY APPLICABLE TO
BARNSTEAD|THERMOLYNE PRODUCTS. BARNSTEAD|THERMOLYNE EXPRESSLY DISCLAIMS
ANY AND ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR USE.
27
Barnstead |Thermolyne • 800-553-0039
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