OHAUS Guardian 3000 User manual

GuardianTM 3000
Hotplate-Stirrer, e-G31
Instruction Manual

GuardianTM Hotplate-Stirrers EN-1
Table of Contents
1. INTRODUCTION..............................................................................................2
1.1. Safety Information...............................................................................2
1.2. Intended Use.......................................................................................3
1.3. Package Contents...............................................................................3
1.4. Installation...........................................................................................4
2. OVERVIEW......................................................................................................5
2.1. Dimensions.........................................................................................5
2.2. Control Panel......................................................................................8
2.3. Display................................................................................................8
3. OPERATION ....................................................................................................9
3.1. Getting Ready.....................................................................................9
3.2. Standby Mode.....................................................................................9
3.3. Controlling the Stirrer........................................................................10
3.4. Controlling the Top Plate Heater.......................................................12
3.5. Using the External Probe..................................................................14
4. THE SETTINGS MENU..................................................................................16
4.1. Accessing / Exiting............................................................................16
4.2. Menu Features..................................................................................17
4.3. Structure & Defaults..........................................................................18
4.4. Using the Single Point Calibration (SPC) Feature.............................19
4.4.1. Start a Single Point Calibration (SPC)..........................................19
4.4.2. Adjust a Calibrated Temperature..................................................22
4.4.3. Clear a Calibrated Temperature...................................................23
4.4.4. Use a Calibrated Temperature .....................................................24
4.5. Enabling / Disabling the Beeper........................................................25
4.6. Changing the Power Recovery Setting.............................................27
4.7. Reset to Factory Default Settings .....................................................29
4.8. Software Version...............................................................................31
4.9. Mode Type........................................................................................32
5. MAINTENANCE .............................................................................................33
5.1 Cleaning............................................................................................33
5.2 Replacing Power Fuse......................................................................34
5.3 Troubleshooting................................................................................35
5.4 Service Information...........................................................................35
6. TECHNICAL DATA.........................................................................................36
7. COMPLIANCE................................................................................................36

EN-2 GuardianTM Hotplate-Stirrers
1. INTRODUCTION
This manual contains installation, operation and maintenance instructions for the
OHAUS GuardianTM 3000 hotplate-stirrer. Please read the manual completely
before using.
1.1. Safety Information
Definition of Signal Warnings and Symbols
Safety notes are marked with signal words and warning symbols. These show
safety issues and warnings. Ignoring the safety notes may lead to personal injury,
damage to the instrument, malfunctions and false results.
WARNING
For a hazardous situation with medium risk, possibly resulting in
severe injuries or death if not avoided.
CAUTION
For a hazardous situation with low risk, resulting in damage to
the device or the property or in loss of data, or minor or medium
injuries if not avoided.
ATTENTION
For important information about the product. May lead to
equipment damage if not avoided.
NOTE
For useful information about the product.
Warning Symbols
General
hazard
Explosion
hazard
Caution, hot
surface
Protective
conductor
terminal
Alternating
current
Electrical shock
hazard
Safety Precautions
WARNING! The protection provided by the unit may be impaired if used
with accessories not provided or recommended by the manufacturer, or
used in a manner not specified by the manufacturer.
•Always operate unit on a level surface for best performance and maximum
safety.
•DO NOT lift unit by the top plate.
•To avoid electrical shock, completely cut off power to the unit by
disconnecting the power cord from the unit or unplugging from the wall outlet.
•Disconnect unit from the power supply prior to maintenance and servicing.
•Spills should be removed promptly, after the unit has cooled down.
•Alkalis spills, hydrofluoric acid or phosphoric acid spills may damage the unit
and lead to thermal failure.
•DO NOT immerse the unit for cleaning.
•DO NOT operate the unit at high temperatures without a vessel/sample on the
top plate.
•DO NOT operate the unit if it shows signs of electrical or mechanical damage.
•Protective earthing of the equipment is achieved via connection of the
provided power cord to a compatible grounded power outlet.

GuardianTM Hotplate-Stirrers EN-3
WARNING: unit is not explosion proof. Use caution when unit is on or when
heating volatile materials.
WARNING! DO NOT use the unit in explosive atmospheres or with
materials that could cause a hazardous environment from processing. Keep
in mind the material flash point relative to the target temperature that has
been set.
CAUTION! The top plate can reach 500°C, DO NOT touch the heated
surface. Use caution at all times. Keep the unit away from explosive vapors
and clear of papers, drapery and other flammable materials. Keep the
power cord away from the heater plate.
CAUTION! Beware of the following risks when heating.
-Flammable materials
-Low boiling point combustible substances
-Glass breakage as a result of mechanical shaking power
-Incorrect container size
-Too much medium
-Unsafe condition of container
Earth Ground - Protective Conductor Terminal
Alternating Current
1.2. Intended Use
This instrument is intended for use in laboratories, pharmacies, schools, businesses
and light industry. It must only be used for processing materials as described in
these operating instructions. Any other type of use and operation beyond the limits
of technical specifications, without written consent from OHAUS, is considered as
not intended. This instrument complies with current industry standards and the
recognized safety regulations; however, it can constitute a hazard in use. If the
instrument is not used according to these operating instructions, the intended
protection provided by the instrument may be impaired.
1.3. Package Contents
•Hotplate Stirrer
•Power Cord
•Stir Bar

EN-4 GuardianTM Hotplate-Stirrers
1.4. Installation
Upon receiving the Ohaus Hotplate-Stirrer, check to ensure that no damage has
occurred during shipment. It is important that any damage that occurred in transport
is detected at the time of unpacking. If you do find such damage, the carrier must
be notified immediately.
After unpacking, place the Hotplate-Stirrer on a level bench or table, away from
explosive vapors. Ensure that the surface on which the unit is placed will withstand
typical heat produced by the unit and place the unit a minimum of six (6) inches
from vertical surfaces. Do not position the equipment such that it is difficult to
disconnect the power cord during use. Always place the unit on a sturdy work
surface.
The Hotplate-Stirrer is supplied with a 3 conductor, grounded power cord that
should be plugged into a matching standard grounded outlet. If the cord supplied
does not meet your needs, please use an approved power cord that has ratings
equal or exceeding those of the originally provided cord and that complies with the
local/national regulations of the country in which the equipment is to be used.
Replacement of the plug must be made by a qualified electrician.

GuardianTM Hotplate-Stirrers EN-5
2. OVERVIEW
2.1. Dimensions
Round Top Hotplate-Stirrer
Overall Dimensions (L x W x H)
264 x 163 x 101 mm (10.4 x 6.4 x 4.0'')
Top Plate Dimensions
Ø 13.5 cm (5.3”)
Top Plate Material
Ceramic coated stainless steel
Electrical (50 / 60 Hz)
100 - 120 V ~5A / 220 - 240 V ~ 4 A
Fuses
10 A, 5 x 20 mm, 250 VAC /
6.3 A, 5 x 20 mm, 250 VAC
Temperature Range
Ambient +5°to 380°C
Temperature Stability of Top Plate+
±3% (> 100°C), ±2°C (≤100°C)
Temperature Stability with Temperature
Probe++
± 2% (> 100°C), ±2°C (≤100°C)
Stir Capacity
15 L
Speed Range
80 to 1600 rpm
Speed Stability++
±2%
Weight Capacity
Up to 15 kg (33 lbs)
Net weight
2.5 kg
Gross Weight
3.1 kg
Shipping Dimension
330 x 250 x 140 mm (13.0 x 9.8 x 5.5
inch)
Note:
⚫+ The parameter in the specification table are applicable to 2” (5 cm) diameter
center of the top plate.
⚫++ Conditions permitting. Variations in temperature and speed measurement
processes, vessel, ambient and sample will impact actual performance. To
improve temperature accuracy of the system, use the Single Point
Calibration feature.

EN-6 GuardianTM Hotplate-Stirrers
4x4 Hotplate-Stirrer
Overall Dimensions (L x W x H)
264 x 163 x 110 mm (10.4 x 6.4 x 4.3'')
Top Plate Dimensions
10.2 x 10.2 cm (4 x 4”)
Top Plate Material
Ceramic
Electrical (50 / 60 Hz)
100 –120 V ~5A / 220 –240 V ~ 4 A
Fuses
10 A, 5 x 20 mm, 250 VAC /
6.3 A, 5 x 20 mm, 250 VAC
Temperature Range
Ambient +5°to 500°C
Temperature Stability of Top Plate+
±3% (> 100°C), ±2°C (≤100°C)
Temperature Stability with
Temperature Probe++
± 2% (> 100°C), ±2°C (≤100°C)
Stir Capacity
15 L
Speed Range
80 to 1600 rpm
Speed Stability++
±2%
Weight Capacity
Up to 15 kg (33 lbs)
Net weight
2.5 kg
Gross Weight
3.1 kg
Shipping Dimension
330 x 250 x 140 mm (13.0 x 9.8 x 5.5
inch)
Note:
⚫+ The parameter in the specification table are applicable to 2” (5 cm) diameter
center of the top plate.
⚫++ Conditions permitting. Variations in temperature and speed measurement
processes, vessel, ambient and sample will impact actual performance. To
improve temperature accuracy of the system, use the Single Point
Calibration feature.

GuardianTM Hotplate-Stirrers EN-7
7x7 Hotplate-Stirrer
Overall Dimensions (L x W x H)
318 x 223 x 112 mm (12.5 x 8.8 x 4.4'')
Top Plate Dimensions
17.8 x 17.8 cm (7 x 7”)
Top Plate Material
Ceramic
Electrical (50 / 60 Hz)
100 - 120 V ~ 10 A / 220 - 240 V ~ 7 A
Fuses
15 A, 5 x 20 mm, 250 VAC /
10 A, 5 x 20 mm, 250 VAC
Temperature Range
Ambient +5°to 500°C
Temperature Stability of Top Plate+
±3% (> 100°C), ±2°C (≤100°C)
Temperature Stability with
Temperature Probe++
± 2% (> 100°C), ±2°C (≤100°C)
Stir Capacity
15 L
Speed Range
80 to 1600 rpm
Speed Stability++
±2%
Weight Capacity
Up to 15 kg (33 lbs)
Net weight
3.9 kg
Gross Weight
4.6 kg
Shipping Dimension
390 x 290 x 160 mm (15.4 x 11.4 x 6.3
inch)
Note:
⚫+ The parameter in the specification table are applicable to 2” (5 cm) diameter
center of the top plate.
⚫++ Conditions permitting. Variations in temperature and speed measurement
processes, vessel, ambient and sample will impact actual performance. To
improve temperature accuracy of the system, use the Single Point
Calibration feature.

EN-8 GuardianTM Hotplate-Stirrers
2.2. Control Panel
1. Display Screen
2. Left Knob: Controls temperature and settings menu.
3. Standby Switch
4. Heater Indicator: Illuminates when heater is running.
5. Hot Top Caution Indicator: Illuminates once the heater temperature reaches
40 °C.
6. Speed Indicator: Illuminates when stirrer is running.
7. Right Knob: Controls speed.
8. External RTD Probe Port
9. Power Entry Module (PEM)
10. Fuse
11. Accessory Rod Mounting Hole
Note: The top plates are of different dimension and material. Please refer to the
actual product for detail.
2.3. Display
1. Heater Temperature: Switches to external probe temperature when the probe
is plugged in and external probe icon is illuminated.
2. Heat Setting Indicator: Switches heater temperature to heat setting when
illuminated.
3. Single Point Calibration Icon
4. External Probe Icon: Illuminates when the external probe is plugged in.
5. Speed Setting Indicator: Illuminates until stirrer reaches the speed setting.
6. Stir Speed
4
5
3
6
2
1
7
8
10
9
11
1
2
3
4
5
6

GuardianTM Hotplate-Stirrers EN-9
3. OPERATION
3.1. Getting Ready
To get ready:
1. Plug the female end of the provided power cord into Power Entry Module
(PEM) on the rear side of the unit.
2. Plug the male end of the power cord into a matching standard grounded outlet.
3. The unit will beep once and the screen will illuminate with the following
displays:
a) The first will display all the icons on the screen. In addition, the Heater
Indicator , the Speed Indicator and the Hot Top Caution
Indicator on the control panel will light up.
b) The second will display the unit type (left) and the software version
(right).
c) The third will display the unit’s electrical voltage (left) and frequency
(right).
d) The forth will display the unit’s main operating screen.
Note: If the fourth screen displays OFF, the unit is in standby mode.
3.2. Standby Mode
The standby switch on the front side of the unit controls standby mode.


EN-10 GuardianTM Hotplate-Stirrers
1. When the unit is switched off:
a) All heating, stirring, and timing functions will turn off.
b) The screen will display OFF.
In addition, If the heater temperature is above 40°C , the on the control
panel will remain illuminated as well as the word HOt on the screen.
2. When the unit is switched on:
a) All heating and stirring functions will remain off.
b) The main operating screen will return to display the previous heating and
stirring settings.
c) The unit is ready for normal use.
3.3. Controlling the Stirrer
1 Rotate the right knob to control the speed setting.
a) Clockwise rotation will increase the speed setting.
b) Counterclockwise rotation will decrease the speed setting.
2 To turn on the stirrer, press and hold the right knob until the unit beeps and the
on the control panel illuminates.
a) The unit will beep once to confirm the stirrer has been turned on.
b) The will blink to indicate that the stirrer is on and ramping to the
target speed.


GuardianTM Hotplate-Stirrers EN-11
c) Once the stirrer has reached the target speed, the Speed Setting
Indicator will disappear from the screen and the will stop
blinking and remain illuminated.
Note: the unit will only display the target speed during the process.
3 To change the speed setting while the stirrer is on:
a) Rotate the right knob clockwise or counterclockwise to the new speed
setting.
The speed number on the screen will blink to indicate that the speed
setting is not confirmed.
b) Briefly press the right knob to confirm the new speed setting.
The speed number on the screen will stop blinking once the new setting
is confirmed.
Note: If the speed setting screen remains idle without confirmation for 6
seconds, it will reset to the current setting.
4 To turn off the stirrer, press and hold the right knob until the unit beeps and the
lights off.
a) The unit will beep once to confirm the stirrer has been turned off.
b) The on the control panel will go off.
c) The on the screen will illuminate.
STIRRING OPERATING TIPS
The stirrer increases speed at a steady rate until the setpoint is reached. If the
stirrer is not reaching its setpoint: 1) the stir bar may be too large, 2) the liquid may
be too viscous, 3) the setpoint speed may need to be reduced. Additionally, the
magnetic strength of stir bars reduce over time and may need to be replaced. Apart
from that, the bottom surface of the vessel can affect the stirring performance of the
magnetic stir bar. Adjust the vessel being used or change the stir bar to optimize
mixing in the sample.



EN-12 GuardianTM Hotplate-Stirrers
When heating and stirring a reaction vessel within an oil bath or similar set-up, the
stirring function will stir up to approximately one inch (2.5 cm) from the top plate.
The stirring speed will vary according to liquid viscosity, spin bar length, and
distance from top plate. Adjust one or all of these to achieve the desired stirring
speed. For example: the closer the reaction vessel is to the top plate, the strong the
magnetic connection between the unit and the stir bar.
3.4. Controlling the Top Plate Heater
1 Rotate the left knob to control the heat setting.
a) Clockwise rotation will increase the heat setting.
b) Counterclockwise rotation will decrease the heat setting.
2 To turn on the heater, press and hold the left knob until the unit beeps and the
illuminates.
a) The unit will beep once to confirm the heater has been turned on.
b) The on the control panel will illuminate to indicate that the heater is
running.
c) During heating, the current heater temperature and the set target
temperature along with the Heat Setting Indicator will be alternately
displayed on the screen, while the will blink.
d) When temperature is reached stably, the screen will display the current
heater temperature and the will stay illuminated.
e) When the heater temperature is above 40°C , the on the control
panel will be illuminated.


GuardianTM Hotplate-Stirrers EN-13
3 To change the heat setting while the heater is on:
a) Rotate the left knob clockwise or counterclockwise to the new heat
setting.
The heating temperature on the screen will blink to indicate that the heat
setting is not confirmed when heating is active. The will stay
illuminated on the screen.
b) Briefly press the left knob to confirm the new heat setting.
The heating temperature on the screen will stop blinking once the new
setting is confirmed.
If the setting temperature remains idle without confirmation for 6 seconds,
it will reset to the current setting.
4 To turn off the heater, press and hold the left knob until the unit beeps and the
lights off.
a) The unit will beep once to confirm the heater has been turned off.
b) The on the control panel will go off.
CAUTION: THIS DOES NOT MEAN THAT THE TOP PLATE IS SAFE
TO TOUCH.
c) Once the heater's temperature cools below 40°C , the on the control
panel will disappear.



EN-14 GuardianTM Hotplate-Stirrers
HEATING OPERATING TIPS
Overshoot:
The unit may overshoot the temperature up to 10°C before stabilizing at the
setpoint. The two methods to minimize overshoot are:
1. Metal containers minimize overshoot.
CAUTION! When heating metal containers on a ceramic top plate, it is
recommended to use the lowest temperature setting possible to limit
thermal stress to the ceramic top plate.
2. If a glass vessel is used, anticipate overshoot. Start with a temperature
setpoint 5 to 10°C below the desired temperature. When the temperature
stabilizes at this lower setting, increase the heater to the final temperature.
Overshoot is then reduced to about 1°C.
The temperature display on the unit represents the estimated top plate temperature,
not the sample temperature.
When external probe is in use, the temperature display on the unit represents the
sample temperature. The vessel contents being heated may be at a lower
temperature depending on the size and thermal conductivity of the vessel.
It may be beneficial to monitor the temperature of the vessel contents and adjust
the setpoint temperature accordingly. If you need precise control, use the Ohaus
External Temperature Probe.
Typical Time to Boil Water
The chart below is an example of an approximate time to boil for the specified
amount of water in a specific vessel. These values are only approximate and can
vary from unit to unit. Values are based on 23°C water in an ambient environment
of 23°C.
Unit Size
Heater Temp. Limit
Volume of Water
Typical Time to Boil
Round Top
400°C
500mL in 1L beaker
≈25 min
7×7
500°C
500mL in 1L beaker
≈18 min
4×4
500°C
500mL in 1L beaker
≈30 min
3.5. Using the External Probe
1. Connect the Ohaus External Temperature Probe to the External RTD
Probe Port on the rear panel of the unit.
Once the Ohaus External Temperature Probe is connected, the External
Probe Icon on the screen will illuminate.
External RTD Probe Port

GuardianTM Hotplate-Stirrers EN-15
2. The display will now show the temperature of the external probe instead of the
heater. An example is as the following:
The will still illuminate once the heater temperature reaches 40°C .
Note: When using the Ohaus External Temperature Probe, the temperature
setpoint should be adjusted to the desired sample temperature. If the
temperature setpoint is higher than the sample can achieve, an E7 will occur
(see the Troubleshooting section). Reduce sample volume or temperature
setpoint value. For Example: Water has a theoretical temperature limit of
100°C (boiling). A temperature setpoint greater than 100°C will cause an E7
error.
3. If the external temperature probe is inserted into the external RTD probe port
while the heater is running:
a) The heater will shut off.
b) The unit will display an E7 error.
c) The unit will beep 10 times.
4. If the external temperature probe is removed from the external RTD probe port
while the heater is running:
a) The heater will shut off.
b) The unit will display an E4 error.
c) The unit will beep 10 times.
Note: To clear an E4 or E7 error, flip the standby switch off and back on. The
unit will be ready for normal use.
30°C
50°C


EN-16 GuardianTM Hotplate-Stirrers
4. THE SETTINGS MENU
4.1. Accessing / Exiting
1. To access the settings menu, press and hold the left knob until mMEN U
appears on the screen.
a) Continue to hold the left knob after the unit beeps and the on the
control panel illuminates.
b) The heater will not turn on unless the left knob is released before mMEN U
appears.
c) The settings menu cannot be accessed while the heater or the stirrer is
running.
d) mMEN U will appear briefly then proceed to the top level of the settings menu.
2. Rotate the left knob to navigate the different menu options and briefly press
the left knob to select / enter / edit the displayed setting.
3. To exit the menu from the top level, rotate the left knob clockwise until ESC is
displayed and briefly press the left knob. The unit will return to the main
operating screen.
Note:
To exit the menu at any time, flip the standby switch off and back on. The unit
will be ready for normal use.
Turning off the unit will not reset / change the settings.





GuardianTM Hotplate-Stirrers EN-17
4.2. Menu Features
The top level of the settings menu has the following features:
1. CAL –Single Point Calibration
Single Point Calibration (SPC) improves the accuracy of the heater at user-
selected temperature points. Up to 1 point (Plate) and 1 point (Probe) can be
stored.
2. SYS –System Settings
System Settings allows the user set additional features, such as enabling /disabling
the Beeper, changing the Power Recovery Setting, and resetting to Factory
Default Settings.
3. ESC
The unit will save the current settings and return to the main operating screen.

EN-18 GuardianTM Hotplate-Stirrers
4.3. Structure & Defaults