Lab-Line 3550 Ambi-Hi-Lo Refrigerated BOD Incubator
The Lab-Line 3550 Ambi-Hi-Lo Refrigerated BOD Incubator is a compact temperature-controlled chamber designed for biochemical oxygen demand testing, microbiology, environmental analysis, water and wastewater laboratories, and other applications requiring stable temperatures above or below normal room conditions. With a 5.5 cu. ft. chamber, operating range of 5°C to 50°C, forced-air circulation, and approximately ±0.5°C temperature uniformity, the Lab-Line 3550 provides a straightforward and dependable platform for routine BOD incubation and other low-temperature laboratory procedures.
Available used and refurbished from American Instrument Exchange, the Lab-Line 3550 is particularly well suited for laboratories that need a dedicated BOD incubator without the size or complexity of a larger programmable environmental chamber. Its compact undercounter-style cabinet provides enough interior capacity for up to 78 standard BOD bottles, while refrigeration allows the incubator to maintain the controlled 20°C conditions commonly required for BOD testing regardless of typical laboratory room temperature.
Key Features
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5.5 cu. ft. refrigerated incubation chamber
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5°C to 50°C operating temperature range
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Approximately ±0.5°C temperature uniformity
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Capacity for up to 78 BOD bottles
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Approximately 6.5 sq. ft. of shelf area
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Forced-air circulation for consistent chamber temperature
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Refrigerated operation for below-ambient incubation
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Three hydraulic thermostats for temperature control and safety
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Independent high- and low-temperature safety thermostats
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Sheathed heating element
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Door-mounted digital temperature display
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Compact undercounter-style configuration
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120V, 60 Hz electrical requirements
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Professionally inspected and temperature tested by American Instrument Exchange
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90-day warranty included
Lab-Line 3550 Ambi-Hi-Lo Overview
The Lab-Line 3550 was designed specifically for laboratory applications requiring dependable temperature control across both below-ambient and elevated conditions. Unlike a conventional general-purpose incubator that can only heat above room temperature, the 3550 incorporates refrigeration and operates from approximately 5°C to 50°C.
That capability is particularly important for biochemical oxygen demand (BOD) testing. Standard BOD procedures commonly require samples to be maintained at a controlled 20°C for several days. In a laboratory where ambient temperature may exceed that setpoint, a conventional warm-air incubator cannot maintain the required conditions. The refrigeration system in the Lab-Line 3550 allows the chamber to actively cool below room temperature and maintain the appropriate incubation environment.
The 5.5 cu. ft. chamber provides approximately 6.5 sq. ft. of shelf area and can accommodate as many as 78 standard BOD bottles. This gives municipal, environmental, industrial, and research laboratories enough capacity for routine sample batches while retaining a relatively compact footprint.
The older Ambi-Hi-Lo platform uses a straightforward electromechanical temperature-control system. Three hydraulic thermostats provide primary temperature regulation along with independent high- and low-temperature safety protection. A sheathed heater provides controlled heat input, while refrigeration handles temperatures below ambient.
Common Applications
The Lab-Line 3550 is particularly well suited for BOD testing in water and wastewater laboratories, including municipal treatment facilities, environmental testing laboratories, industrial wastewater operations, and research facilities. It can also support general microbiological incubation, serum studies, enzyme assays, sample conditioning, environmental testing, and other procedures requiring stable temperatures between 5°C and 50°C.
For water-quality laboratories, the combination of refrigeration and a chamber designed around BOD bottle capacity makes the 3550 considerably more appropriate than a standard microbiological incubator. Samples can remain at a stable controlled temperature throughout multi-day testing without being affected by normal fluctuations in laboratory ambient conditions.
The chamber can also serve broader laboratory applications when dedicated humidity, CO₂, or programmable environmental control is not required. Laboratories performing complementary sample-preparation work may use the 3550 alongside laboratory centrifuges, laboratory refrigerators, laboratory freezers, and other laboratory incubators.
Sample Types & Incubation Recommendations
The Lab-Line 3550 is best viewed as a refrigerated BOD and general-purpose incubator rather than a specialized cell culture or environmental chamber. Its broad temperature range allows it to support a variety of laboratory samples while its chamber configuration is particularly well suited for bottled water and wastewater samples.
Common Samples & Applications
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BOD water samples
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Municipal wastewater samples
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Industrial wastewater samples
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Environmental water samples
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Microbiological cultures
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Serum samples
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Enzyme assay samples
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General laboratory specimens requiring refrigerated incubation
Typical Laboratory Vessels
For laboratories performing routine BOD analysis, the 78-bottle capacity is an especially useful specification. It provides enough room for multiple samples, blanks, controls, and replicate bottles within a single controlled-temperature chamber.
Because the Lab-Line 3550 does not regulate CO₂ or relative humidity, it should not be considered a substitute for a dedicated CO₂ cell culture incubator or humidity chamber. Its strength is reliable refrigerated temperature control for BOD, microbiological, and general laboratory applications.
Temperature Control & Environmental Stability
The Lab-Line 3550 combines refrigeration, controlled heating, and forced-air circulation to maintain temperatures from approximately 5°C to 50°C. This allows the chamber to operate both below and above typical laboratory ambient conditions.
Forced-air circulation continuously moves conditioned air through the chamber, helping reduce temperature gradients between samples located on different shelves. Temperature uniformity is approximately ±0.5°C, providing consistent conditions for BOD testing and other procedures where samples must remain within a relatively narrow temperature range.
The Ambi-Hi-Lo design incorporates three hydraulic thermostats. One serves as the primary temperature controller, while separate high- and low-temperature safety thermostats provide backup protection against excursions outside acceptable limits. This straightforward control arrangement reflects the vintage of the equipment but provides an important layer of protection for samples during extended incubation.
A digital thermometer mounted on the door provides convenient chamber-temperature monitoring without requiring users to open the incubator. Minimizing unnecessary door openings helps reduce environmental disturbances during multi-day testing.
For BOD testing in particular, refrigeration is critical. A target temperature such as 20°C may be below the surrounding laboratory temperature during much of the year. The Lab-Line 3550 can actively remove heat rather than relying on ambient conditions, helping maintain the consistent environment required throughout the incubation period.
The combination of refrigerated operation, forced-air circulation, independent safety thermostats, and compact BOD-focused capacity makes the Lab-Line 3550 a practical older-generation incubator for laboratories that need reliable temperature control without sophisticated programmable features.
Lab-Line 3550 Ambi-Hi-Lo Specifications
| Specification |
Details |
| Manufacturer |
Lab-Line Instruments |
| Model |
3550 Ambi-Hi-Lo |
| Equipment Type |
Refrigerated BOD Incubator |
| Chamber Capacity |
5.5 cu. ft. |
| Temperature Range |
5°C to 50°C |
| Temperature Uniformity |
±0.5°C |
| Refrigeration |
Yes |
| Heating |
Sheathed heating element |
| Air Circulation |
Forced-air |
| Temperature Control |
Hydraulic thermostat |
| Safety Controls |
Independent high- and low-temperature thermostats |
| Temperature Display |
Digital thermometer |
| BOD Bottle Capacity |
Up to 78 bottles |
| Shelf Area |
Approximately 6.5 sq. ft. |
| Shelving |
Adjustable |
| Interior Dimensions (W × D × H) |
19.5" × 15" × 22" |
| Exterior Dimensions (W × D × H) |
24" × 24" × 34.5" |
| Electrical Requirements |
120V, 60 Hz |
| Approximate Current |
4–4.5 A, configuration dependent |
| Approximate Power |
480 W |
| Approximate Shipping Weight |
115 lb. |
Specifications can vary slightly according to production date and individual unit configuration. Confirm electrical requirements, shelving, accessories, and other specifications for the individual incubator before purchase.
Lab-Line 3550 Ambi-Hi-Lo Frequently Asked Questions
What is the Lab-Line 3550 primarily used for?
The Lab-Line 3550 is particularly well suited for biochemical oxygen demand (BOD) testing, including water and wastewater analysis. Its refrigerated temperature control also makes it useful for microbiology, serum studies, enzyme assays, and other laboratory procedures requiring temperatures from 5°C to 50°C.
Why is refrigeration important for BOD testing?
BOD testing commonly requires samples to be incubated at 20°C for an extended period. Because normal laboratory temperatures can exceed 20°C, a refrigerated incubator can actively cool the chamber to maintain the required test conditions rather than relying on room temperature.
How many BOD bottles can the Lab-Line 3550 hold?
The Lab-Line 3550 is designed to accommodate up to approximately 78 standard BOD bottles within its 5.5 cu. ft. chamber, making it suitable for laboratories processing multiple samples, controls, and replicates simultaneously.
What does Ambi-Hi-Lo mean on the Lab-Line 3550?
The Ambi-Hi-Lo designation reflects the chamber's ability to operate across temperatures below and above normal ambient conditions along with its high- and low-temperature safety controls. Refrigeration provides below-ambient operation, while the heating system allows temperatures up to approximately 50°C.
Is the Lab-Line 3550 a CO₂ incubator?
No. The Lab-Line 3550 is a refrigerated BOD/general-purpose incubator and does not regulate CO₂ concentration. Laboratories performing conventional mammalian cell culture should use a dedicated CO₂ incubator instead.
Is this Lab-Line 3550 refurbished?
Used Lab-Line 3550 incubators offered by American Instrument Exchange are inspected, cleaned, and tested prior to shipment. Temperature-controlled equipment is tested using calibrated monitoring equipment to verify temperature accuracy and performance, while refrigeration, heating, circulation, safety controls, and other functions are evaluated as applicable. Refurbished equipment includes a 90-day warranty.
