Barnstead International MIRAK 725 Series User manual

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
HP72938-60 208 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 • 9/19/02

Safety Information ..............................................................................................................................................3
Alert Boxes ..................................................................................................................................................3
Warnings ......................................................................................................................................................3
Introduction..........................................................................................................................................................5
Unpacking ..........................................................................................................................................................6
Installation ..........................................................................................................................................................8
Principles of Operation........................................................................................................................................9
Operation ..........................................................................................................................................................10
Removing the Clear Plastic Cover..............................................................................................................10
The Power Switch ......................................................................................................................................10
Setting the Stirring Speed ..........................................................................................................................10
Stirring Speed Guide ..................................................................................................................................11
Setting the Temperature..............................................................................................................................11
Controlling Top Plate Temperature ............................................................................................................12
Controlling Solution Temperature ..............................................................................................................12
Calibrating the Probe Temperature Input....................................................................................................13
Using the Probe with the Temperature Display for Stirring-only Applications ............................................14
To Achieve Fast Heat-up of Large Volumes ..............................................................................................15
Heating Small Volumes ..............................................................................................................................15
Heating Metal Vessels and Sand Baths ....................................................................................................15
Heat-up Time Guide....................................................................................................................................16
Operating Specifications ..................................................................................................................................17
Heating Specifications ................................................................................................................................17
Stirring Speed Specifications......................................................................................................................17
General Operating Specifications ....................................................................................................................18
Dimensions- 7" x 7" Models\l 2 ..................................................................................................................18
Dimensions- 12" x 12" Models\l 2 ..............................................................................................................18
Electrical Ratings- 7" x 7" Models\l 2..........................................................................................................18
Electrical Ratings- 12" x 12" Models\l 2......................................................................................................19
Temperature Range for Hot Plates and Stirring Hot Plates........................................................................19
Stirring Speed Range for Stirrers and Stirring Hot Plates ..........................................................................19
Environmental Parameters for all units ......................................................................................................19
Maintenance and Servicing ..............................................................................................................................20
Replacing the Power Board........................................................................................................................20
Replacing the Logic Board ........................................................................................................................21
Replacing the Display Board ......................................................................................................................21
Replacing the Motor....................................................................................................................................22
Replacing the Top Plate Assembly ............................................................................................................23
Set-up Procedure........................................................................................................................................24
Troubleshooting Guide ......................................................................................................................................27
Replacement Parts List ....................................................................................................................................31
Ordering Procedures ........................................................................................................................................33
Warranty ............................................................................................................................................................36
2
Table of Contents

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 con-
formance with local electrical codes.
Warnings
To avoid electrical shock, always:
1. Use a properly grounded electrical outlet of cor-
rect 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, hydro-fluoric 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
3
Safety Information
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.
Alert Signals

plate will remain hot without any visual indica-
tion for some time after power has been
removed.
8. Do not use in highly corrosive atmospheres; cor-
rosive fumes and spill may damage top and
internal components, creating shock hazard.
9. Refer servicing to qualified personnel.
Please note the following WARNINGS:
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 con-
tains refractory ceramic, refractory ceramic fiber or fiber-
glass insulation, which can produce respirable dust or
fibers during disassembly. Dust or fibers can cause irrita-
tion 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 indi-
cate that there is no risk of exposure to dust or respirable
fibers resulting from operation of this product under nor-
mal 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 pro-
tective equipment you can work safely with these insulat-
ing materials and minimize any exposure. Refer to the
appropriate Material Safety Data Sheets (MSDS) for infor-
mation regarding proper handling and recommended pro-
tective equipment. For additional MSDS copies, or addi-
tional information concerning the handling of refractory
ceramic products, please contact the Customer Service
Department at Barnstead International at 1-800-553-0039.
4
SAFETY INFORMATION
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.
Warning
Refer servicing to qualified personnel.

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 con-
trol of temperature and/or stirring speed. Each MIRAK
model includes a digital display for monitoring actual tem-
perature or stirring speed, and the stirring hot plate mod-
els have dual displays so temperature and stirring speed
can be monitored simultaneously. The hot plate is capa-
ble of producing accurately controlled top plate tempera-
tures 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 stain-
less steel immersion probe, or a chemical-resistant 7"
solid Teflon® immersion probe may be ordered separate-
ly. 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 gen-
eral laboratory mixing of solutions, including sample
preparation, heating reagents, melting paraffin, warming
resinous chemicals, content analysis, solvent evapora-
tions, digestions, media preparation and sterilization, titra-
tions, sand baths, and microscale chemistry applications.
5
Introduction

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
International Customer Service at 800-553-0039. Remove
the packaging from underneath the top plate by gently
pulling the packaging material toward you.
6
Unpacking
Note
Aspecial 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.
Note
A12" x 12" 120 volt MIRAK hot plate
and stirring hot plate (HP72935-60,
SP73035-60) is available with a stan-
dard 15-amp, 120 volt cordset. These
models are not CSA-approved.

7
UNPACKING

Set the unit on a flat stable surface at least 12" away from
combustible materials, and plug the cordset into a proper-
ly 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 dis-
play(s) should illuminate. The unit is ready for operation.
8
Installation
Warning
Use a properly grounded electrical
outlet of correct voltage and current
handling capacity.
Do not remove or modify grounded
power plug. Use only properly ground-
ed outlets to avoid shock hazard. Not
rated for use in hazardous atmos-
pheres.
Do not use in the presence of flamma-
ble or combustible materials; fire or
explosion may result. This device con-
tains components which may ignite
such materials.
Do not use in highly corrosive atmos-
pheres; corrosive fumes and spill may
damage top and internal components,
creating shock hazard.
Note
Some misalignment of the motor bear-
ings 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.

Each MIRAK unit utilizes the latest in microprocessor
technology to deliver the most reliable, accurately con-
trolled, ceramic top hot plate, stirrer and stirring hot plate
on the market.
Your MIRAK hot plate or stirring hot plate has an electron-
ic 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 measure-
ment 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 measur-
ing both the top plate temperature, and the solution tem-
perature when using the probe. Both top plate surface
and probe temperature are measured with independent
analog circuits. This provides a significant increase in reli-
ability 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 dam-
aging the ceramic top. However, we recommend that you
do not control the temperature with the probe when heat-
ing 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 dis-
played 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.
9
Principles of Operation

Removing the Clear Plastic
Cover
Your MIRAK unit has a protective plastic cover over the
front control panel. This plastic cover is designed to pro-
tect 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 bot-
tom 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.
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 sep-
arate power switch allows you to turn your MIRAK hot
plate, stirrer or stirring hot plate on or off without disturb-
ing your temperature and/or speed setting. Your last set-
point 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 solu-
tion.) 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
10
Operation
Warning
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 protec-
tion when handling hazardous chemi-
cals.
"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.

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 illumi-
nated. To check your setpoint, move the knob counter-
clockwise 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 auto-
matically return to indicating actual speed and the SET
light will go out. To stop the stirring action without chang-
ing your setpoint press the knob once. To resume stirring
at the set speed, press the knob again. If you want to
ensure that the unit will not start to stir if the knob is inad-
vertently pressed, turn the speed control knob until the
display indicates the word OFF.
11
OPERATION
Stirring Speed Guide
Unit Flask Size Stirbar Size Amt. in Solution Viscosity Max Speed
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 1100 rpm
motor oil
*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 provid-
ed above for the 7" X 7" units. For speed stability and display accuracy please refer to the Operating
Specifications.
Setting the Temperature
Your MIRAK hot plate or stirring hot plate has an electron-
ic closed-loop feedback control which will accurately main-
tain 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 tem-
perature 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 dis-
played for approximately five seconds until the display returns
to indicating the actual temperature.
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'.
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 unground-
ed 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.
The solution probe offers more exact temperature control than
regulating the top plate by the internal sensor. If you need to
12
OPERATION
Note
The temperature display will not indi-
cate 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.
Note
The top plate temperature will be
higher than your solution tempera-
ture.

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 solu-
tion, 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.
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 cen-
ter of the stirring vortex. Drafts and other temperature
fluctuations will affect temperature accuracy.
Calibrating the Probe
Temperature Input
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 illustra-
tion of interior of unit or the exploded view).
Move the jumper from position J11 to position
J1. For 100 and 120 volt units, you must remove
jumper J3 if it exists.
3. Replace the bottom of the unit and turn the unit
over.
13
OPERATION
Warning
If the probe is plugged into your stir-
ring 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
The top plate temperature will not
exceed the 540°C maximum.
Note
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

4. Calculate the necessary correction for the probe
using the following equation:
Probe Error= (displayed temperature) - (actual
temperature measured by other source)
Correction= 350 - Probe Error (if the error is
negative, the correction is >350)
5. Turn the unit on. The display will show "888"
and then "000". The HOT, PROBE, SET and
TOP LED's will be on. Push the heat knob once.
The digit on the far right side will get brighter.
6. Turn the heat knob clockwise until the display
shows the correction calculated above. Push the
heat knob again. The SET, TOP, and PROBE
LED's will go out. The correction will remain on
the display.
7. Unplug unit, turn unit upside down and remove
screws from bottom. Move jumper J1 to one pin
of J11. For 100 and 120 volt units, replace
jumper J3 if necessary.
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 uti-
lized 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 temper-
ature remains at less than 40°C, or the actual tempera-
ture of your solution if it is above 40°C.
14
OPERATION
Note
The maximum error is ±10. Thus the
correction must be between 340 and
360.

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 approximate-
ly 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 solu-
tion.
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.
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.
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
15
OPERATION
Note
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 natu-
ral cooling characteristics of ceramic,
the temperature of the top will drop
much more gradually after the top
plate temperature reaches 200°C.

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 tempera-
tures. 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.
16
OPERATION
Heat-up Time Guide
Unit Temperature Flask Size Amount of Solution Time to
Setpoint Vigorous Boil
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.
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.

Heating Specifications
Top Plate Surface - Solid Ceramic
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. 40°C to 370°C
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). ± 1.0°C
Controlled by the top plate at 70°C setpoint (solution maintained at 30°C).
Controlled by the Barnstead|Thermolyne recommended immersion probe ± 1.0°C
at 70°C setpoint (solution maintained at 70°C).
Accuracy of the temperature display vs the actual temperature at the center of the ± 4.0°C
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 ± 2.0°C
by the stainless steel or Teflon® immersion probe (setpoint 70°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
Top Plate Size Max Recommended Flask Size Max Weight on Top Plate
7" x 7" 4 liters 25 lbs
12" x 12" 6 liters 30 lbs
17
Operating Specifications

Dimensions- 7" x 7" Models
Model Numbers HP72620 SP72720 S72520
HP72620-26 SP72720-26 S72520-26
HP72624 SP72724 S72524
HP72625 SP72725 S72525
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 SP73030
HP72930-26 SP73030-26
HP72934 SP73034 S72830
HP72935 SP73035 S72830-26
HP72935-60 SP73035-60 S72834
HP72938 SP73038 S72835
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)
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General Operating Specifications
Electrical Ratings- 7" x 7" Models
Model No. Volts Amps Watts Freq. Phase
HP72620 220-240 4.6 1100 50/60 1
HP72620-26 220-240 4.6 1100 50/60 1
HP72624 100 11.0 1100 50/60 1
HP72625 120 9.2 1100 50/60 1
S72520 220-240 0.14 19.4 50/60 1
S72520-26 220-240 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 220-240 4.7 1119 50/60 1
SP72720-26 220-240 4.7 1119 50/60 1
SP72724 100 11.3 1117 50/60 1
SP72725 120 9.5 1119 50/60 1

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GENERAL OPERATING SPECIFICATIONS
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
HP72935-60 120 13.5 1620 50/60 1
HP72938 208 13.9 2900 50/60 1
S72830 220-240 0.22 30 50/60 1
S72830-26 220-240 0.22 30 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 100 16.8 1671 50/60 1
SP73035 120 13.8 1642 50/60 1
SP73035-60 120 13.8 1642 50/60 1
SP73038 208 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" stirrers are suit-
able for use in a 37°C non-condensing
incubator or in a cold room at -4°C

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.
Maintenance and Servicing
Warning
Disconnect from power supply before
servicing.
Keep top surface clean. Use a non-
abrasive cleaner. Alkali spills, hydro-
fluoric 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 dam-
aged by etching, scratching or chip-
ping. A damaged top can break in use.
Refer servicing to qualified personnel.
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