Critical Factors When Buying OHAUS Guardian Hotplate Stirrers
Compare the Guardian 2000 to 7000 Series hotplate stirrers, explore all OHAUS smart technologies, and find the best top plate material for your applications.
Adding OHAUS Guardian Series hotplate stirrers to your lab is a smart way to modernize and enhance your lab processes. They provide a balanced combination of function and performance, and they excel through the use of intelligent monitoring systems that automate safety.
Use this guide to explore the capabilities of the entire lineup, from the advanced 7000 Series models down to the basic 2000 Series units, and make the right decision in upgrading your lab.
How Does Each OHAUS Guardian Series Stand Out?
Here's a closer look at the complete Guardian Series to help you select the most suitable OHAUS hotplate stirrer for your applications.
Guardian 7000 Series
The Guardian 7000 Series is the flagship of the line and is the only one to be equipped with the entire suite of OHAUS Smart Technologies, especially SmartLink™ and SmartPresence™. It is ideal for use in regulated industries like pharmaceuticals and biotech, organic synthesis, and any application where unattended operation is a necessity.
The 7000 Series features a temperature range of Ambient + 5℃ to 500℃ and stirring speeds from 60 to 1,600 rpm. It allows you to store up to five multi-step programs, and features a USB port for easy data logging and a hardened glass front panel that can withstand chemical splashes.
Guardian 5000 Series
The Guardian 5000 Series offers versatility and high-end performance. Even without some of the advanced features of the 7000 Series, the 5000 Series offers digital precision ideal for university research labs, quality control testing, and general chemistry applications.
The hotplate stirrers in this series come with the SafetyHeat™, SmartHeat™, SmartRate™, and SmartHousing™ features. They maintain a stirring capacity of up to 22 L and offer temperature stability of ±1%. The OHAUS Guardian 5000 models feature three distinct temperature control modes and support three-point calibration of both the plate and the optional probe.
Guardian 3000 Series
The Guardian 3000 Series brings digital control into a more affordable tier. While it lacks certain advanced programming found in the 7000 Series and 5000 Series hotplate stirrers, it retains core safety and durability features, such as SmartHeat™ and SmartHousing™.
The OHAUS Guardian 3000 Series offers a digital LCD display for temperature and speed control, stirring up to 1,600 rpm with a 15 L capacity. It also includes a single-point calibration feature, which is a welcome inclusion, given its entry-level status among digital hotplate stirrers. With affordability and reliability combined, the 3000 Series is recommended for advanced high school and undergraduate labs, as well as budget-conscious industrial environments.
Guardian 2000 Series
The Guardian 2000 Series is OHAUS's most basic offering. The series models are analog and feature basic overheat protection, but still have a rugged metal housing, which is sufficient to protect the unit during sample preparation, boiling, and analog demonstrations in educational settings.
These hotplate stirrers stir samples at speeds from 200 to 1,600 rpm and reach temperatures up to 500℃ on units with a ceramic top. When the surface temperature is above 40℃, even with heating turned off, the Hot Top indicator light remains active.
OHAUS Guardian Series Overview
| Guardian 7000 | Guardian 5000 | Guardian 3000 | Guardian 2000 | |
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| Control Type | Digital | Digital | Digital | Analog |
| Functions | Heat & Stir | Heat, Stir, Heat & Stir | Heat & Stir | Heat, Stir, Heat & Stir |
| Max Temperature Range | Up to 500°C | Up to 550°C | Up to 500°C | Up to 500°C |
| Speed Range | 60 - 1600 rpm | 60 - 1600 rpm | 80 - 1600 rpm | 200 - 1600 rpm |
| Stir Capacity | Up to 20 L | Up to 22 L | 15 L | 15 L |
| Plate Material | Ceramic, Aluminum | Ceramic, Resin, Aluminum | Ceramic, Ceramic Coated Steel | Ceramic, Resin, Ceramic Coated Steel |
| Overheat Protection | Yes | Yes | Yes | Yes |
| SafetyHeat™ | Yes | Yes | Yes | - |
| SmartHousing™ | Yes | Yes | - | |
| SmartPresence™ | Yes | - | ||
| SmartRate™ | Yes (Temperature & Speed) | - | ||
| SmartHeat™ | Yes | - | ||
| SmartLink™ | Yes | - | ||
| Programmability | Yes | - | ||
| Calibration | 5-Point | 3-Point | 1-Point | - |
Which OHAUS SMART Technologies Do You Need?
Before diving into the different Guardian Series models, it is essential to understand the various technologies found in the wide range of OHAUS hotplates and stirrers.
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SafetyHeat™: This internal protection system features dual sensors that constantly check the unit's health and will shut down the heater if it detects a malfunction, eliminating the risk of thermal runaway.
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SmartHeat™: This allows users to set maximum temperature limits, preventing sensitive samples from overheating. It also ensures that the unit will not exceed the predefined temperature limit, even if a user enters a higher set point or accidentally turns the dial.
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SmartRate™: This lets users control the unit's heating and stirring ramp rates until it reaches its setpoint. For stirring, it prevents magnetic stir bars from decoupling or spinning out when trying to move high-viscosity liquids. For heating, it protects delicate reactions from overshooting temperatures.
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SmartPresence™: This IR sensor-based safety feature automatically shuts off the unit's heater once it detects no one is nearby within a user-defined timeframe.
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SmartLink™: This adds another layer of security, using Bluetooth connectivity as its means of detecting nearby movements. It requires pairing the unit with a mobile device and relies on the connection strength to determine if the user has moved out of range. Upon detection, it automatically stops the unit's heating function.
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SmartHousing™: This special housing is chemical-resistant and features a sloped shape, which channels spills away from the internal electronics and control knobs. This design protects the unit's important components from corrosion and short-circuits.
Which Guardian Top Plate Material Suits Your Tasks?
When selecting your Guardian series unit, you will choose from one of the following five materials based on your application needs:
#1 Ceramic
Ceramic tops offer the highest level of chemical resistance, are very easy to clean, and have a bright white surface that serves as an excellent background for observing subtle color changes in your samples. However, ceramic is a thermal insulator, meaning it takes longer to heat up and cool down, and it can be susceptible to thermal shock.
#2 Aluminum
Aluminum is known for being an outstanding thermal conductor, which ensures that the entire surface reaches the target temperature quickly and maintains that temperature across the surface. While it is durable and won't crack or chip like ceramic, it is more prone to scratching and corrosion from strong acids.
#3 Ceramic-Coated Aluminum
Ceramic-coated aluminum offers aluminum's fast, uniform heating properties, but with an added layer of ceramic protection on the surface. This coating provides better chemical resistance than bare metal while maintaining much higher thermal conductivity than a solid ceramic plate.
#4 Ceramic-Coated Stainless Steel
Ceramic-coated stainless steel is ideal for units that are likely to be subjected to rougher handling or more aggressive processing. Stainless steel provides physical durability and impact resistance, while the ceramic coating protects the metal from chemical reactions.
#5 Resin
Resin tops are recommended for low-temperature applications and are often used in life science applications or sensitive stirring tasks. They allow samples to remain at or near ambient temperatures without any risk of contamination from the plate material itself.
Have you decided which OHAUS Guardian hotplate stirrer you’ll be getting? If you still need guidance, The Lab Depot team can help you find the models that best match your lab needs. Contact us at 1-800-733-2522, email, or through live chat on our website.