Thermo Scientific NESLAB Merlin M33 Recirculating Chiller

Brand : Neslab

Product Code : SKU 1486C CIRC

Quantity

Price Match Policy

Shipping

All products ship from our 30,000 sq. ft. Haverhill, MA warehouse

Thermo Scientific NESLAB Merlin M33 Recirculating Chiller

The Thermo Scientific NESLAB Merlin M33 Recirculating Chiller is a compact refrigerated cooling system designed for laboratory instruments, analytical equipment, and other applications requiring continuous closed-loop heat removal. With approximately ±0.1°C temperature stability, more than 1 kW of refrigeration capacity at a 20°C setpoint, and multiple available circulation-pump configurations, the Merlin M33 provides dependable temperature control in a relatively compact floor-standing package.

Available used and refurbished from American Instrument Exchange, the NESLAB Merlin M33 can be used with analytical instruments, lasers, condensers, vacuum systems, reaction equipment, and other laboratory systems requiring controlled liquid cooling. The Merlin platform was designed for continuous operation, straightforward temperature control, and flexible integration with laboratory and process equipment. A 90-day warranty is included.

Key Features

Thermo Scientific NESLAB Merlin Series recirculating chiller
Approximately ±0.1°C temperature stability
More than 1 kW cooling capacity at a 20°C setpoint
Low-temperature configurations capable of operation down to approximately -15°C
Maximum setpoint temperature approximately +35°C
Compact 1.8 L / 0.5 gal reservoir
R134a refrigerant
Digital temperature controller
User-adjustable high- and low-temperature safety limits
Audible alarm capability
Multiple circulation-pump configurations available within the M33 platform
Closed-loop external equipment cooling
Air-cooled refrigeration system
Compact footprint relative to cooling capacity
Designed for continuous laboratory and process cooling
Used, refurbished, and tested by American Instrument Exchange
90-day warranty included

Overview

The NESLAB Merlin M33 is a refrigerated recirculating chiller designed to continuously remove heat from externally connected laboratory equipment. It succeeded earlier generations of NESLAB process chillers and combines a relatively compact footprint with more than 1 kW of refrigeration capacity at typical laboratory coolant temperatures.

The M33 uses an integrated refrigeration system, reservoir, circulation pump, and digital temperature controller to maintain a controlled supply of heat-transfer fluid. Coolant is pumped through the external instrument or process, absorbs heat, and returns to the chiller where that heat is removed by the refrigeration system.

The Merlin M33 was manufactured in several configurations, including different pump and temperature-range options. This allowed users to select circulation characteristics appropriate for either relatively unrestricted cooling circuits or applications requiring higher pump pressure.

Because these configurations can materially affect performance, buyers of a used Merlin M33 should verify the installed pump and exact electrical and temperature configuration of the individual unit.

Key Specifications

Specification	Details
Manufacturer	Thermo Scientific / NESLAB
Model	Merlin M33
Equipment Type	Refrigerated recirculating chiller
Temperature Range	Configuration dependent; low-temperature versions to approximately -15°C, maximum +35°C
Temperature Stability	Approx. ±0.1°C
Cooling Capacity at 20°C	Approx. 1.1–1.25 kW, depending on configuration/generation
Reservoir Capacity	1.8 L / 0.5 gal
Refrigerant	R134a
Pump Configuration	Verify installed pump
Available Pump Types	MD30, PD1, or PD2 depending on configuration
Temperature Control	Digital
Condenser	Air-cooled
Ambient Operating Range	Approx. +10°C to +35°C
Exterior Dimensions	Approx. 12.6 in. W × 20.9 in. D × 23.5 in. H
Weight	Approx. 119 lb / 54 kg
Electrical Requirements	Verify individual unit nameplate
Warranty	90 days

Common Applications

The Thermo Scientific NESLAB Merlin M33 is suitable for laboratory and process equipment requiring continuous removal of moderate heat loads. Typical applications include analytical instruments, lasers, spectrometers, condensers, vacuum equipment, laboratory reactors, semiconductor equipment, imaging systems, and other temperature-sensitive scientific equipment.

With more than 1 kW of cooling capacity at approximately 20°C, the M33 can support substantially greater thermal loads than small 200–500 W laboratory chillers while remaining considerably smaller than large industrial process chillers.

The Merlin M33 can also provide a closed-loop alternative to once-through facility-water cooling for compatible instruments. Instead of continuously consuming and discharging tap water, the M33 recirculates a controlled volume of refrigerated heat-transfer fluid.

This can reduce water consumption while providing more consistent coolant temperature and circulation conditions.

Ideal Laboratory Types

The NESLAB Merlin M33 is well suited for analytical laboratories, biotechnology and pharmaceutical facilities, chemistry laboratories, materials-science groups, spectroscopy laboratories, laser research facilities, semiconductor and electronics laboratories, industrial R&D groups, and academic research facilities.

Its combination of compact size and approximately 1.1–1.25 kW cooling capacity makes it particularly useful where meaningful heat removal is required but space does not justify a much larger process chiller.

The M33 may also be attractive for laboratories maintaining older analytical instruments that were originally designed around NESLAB closed-loop cooling systems.

Temperature Control & Stability

The NESLAB Merlin M33 provides approximately ±0.1°C temperature stability under appropriate operating conditions.

Merlin M33 systems were produced in different temperature configurations. Standard configurations typically operated from approximately +5°C to +35°C, while low-temperature configurations extended the lower setpoint to approximately -15°C.

The exact temperature range of the individual chiller should therefore be verified before installation.

Cooling capacity also varies with operating temperature. Manufacturer documentation places M33 cooling performance at more than 1 kW at a 20°C process setpoint, with available refrigeration capacity decreasing as coolant temperature is reduced.

For applications operating near the lower end of the chiller's range, buyers should evaluate the actual process heat load against the available cooling capacity at the required temperature rather than relying only on the nominal capacity measured at 20°C.

Appropriate heat-transfer fluid should be used for subambient operation.

Circulation & Pump Performance

The NESLAB Merlin M33 was available with multiple circulation-pump configurations, making pump identification particularly important when selecting a used unit.

Depending on configuration, M33 systems could be equipped with a magnetic-drive pump or one of several positive-displacement pump options. These pumps provide substantially different combinations of maximum flow and pressure.

A magnetic-drive configuration favors greater flow at relatively modest pressure and can be appropriate for less restrictive cooling circuits. Positive-displacement configurations provide considerably greater pressure for instruments with narrow passages, longer circulation loops, or greater hydraulic resistance.

For this reason, a generic pump specification should not be applied to every Merlin M33.

Customers with defined flow or pressure requirements should contact American Instrument Exchange so the installed pump on the individual unit can be identified and compared with the requirements of the connected equipment.

Refurbishment & Testing

This used Thermo Scientific NESLAB Merlin M33 Recirculating Chiller is refurbished and tested by American Instrument Exchange before shipment. Our technicians inspect the refrigeration system, compressor, circulation pump, reservoir, temperature controller, display, condenser, electrical components, safety controls, and external fluid connections.

Temperature-controlled equipment is tested using NIST-traceable probes and data loggers. The refrigeration system is operated for extended periods to evaluate temperature pull-down, cooling performance, circulation, temperature regulation, controller operation, and overall system stability.

The reservoir and accessible fluid-contact components are cleaned and inspected before shipment.

Customers with specific coolant-temperature, thermal-load, flow, or pressure requirements are encouraged to provide those conditions before shipment. When practical, American Instrument Exchange can incorporate customer-requested operating conditions into final testing.

A 90-day warranty is included with this refurbished NESLAB Merlin M33.

Choosing the Right Recirculating Chiller

The NESLAB Merlin M33 occupies a useful position between small laboratory chillers and substantially larger process cooling systems.

With more than 1 kW of refrigeration capacity at approximately 20°C, it can support applications that exceed the capabilities of compact 200–500 W chillers without requiring the footprint, electrical service, or cooling capacity of a multi-kilowatt process chiller.

Pump configuration should be considered just as carefully as cooling capacity. Because the M33 was available with different circulation pumps, buyers should determine whether their application favors high flow at modest pressure or requires a higher-pressure positive-displacement system.

Temperature requirements are another consideration. Low-temperature M33 configurations can operate substantially below ambient temperature, while standard versions have a higher minimum setpoint.

American Instrument Exchange can help identify the configuration of an available Merlin M33 and compare it with your required coolant temperature, thermal load, flow, pressure, and electrical service.

Related Equipment

American Instrument Exchange stocks a range of laboratory circulators, including Thermo Scientific and NESLAB recirculating chillers, refrigerated/heated circulators, compact laboratory chillers, and high-capacity process cooling systems. Laboratories using the NESLAB Merlin M33 may also require reactors and fermenters, evaporators and extractors, laboratory water baths, or other refurbished laboratory equipment.

Thermo Scientific NESLAB Merlin M33 Frequently Asked Questions

What is the temperature range of the NESLAB Merlin M33?

The exact range depends on configuration. Standard Merlin M33 systems typically operate from approximately +5°C to +35°C, while low-temperature configurations can extend the minimum setpoint to approximately -15°C.

How much cooling capacity does the Merlin M33 provide?

Manufacturer literature places M33 cooling capacity at more than 1 kW at a 20°C process temperature, with published figures varying somewhat by generation and configuration.

How stable is the temperature?

The NESLAB Merlin M33 provides temperature stability of approximately ±0.1°C under appropriate operating conditions.

What is the reservoir capacity of the Merlin M33?

The M33 has a compact 1.8 L, or approximately 0.5 gallon, internal reservoir.

What type of pump does the Merlin M33 use?

The M33 was offered with multiple pump options, including magnetic-drive and positive-displacement configurations. The pump installed in the individual chiller should be verified when an application has specific flow or pressure requirements.

Can the Merlin M33 replace tap-water cooling?

In many compatible applications, yes. The Merlin M33 provides refrigerated closed-loop cooling that can reduce continuous facility-water consumption while providing controlled coolant temperature and circulation.

What refrigerant does the NESLAB Merlin M33 use?

The Merlin M33 uses R134a refrigerant.

Is the Merlin M33 suitable for analytical instruments?

Yes. Its compact design and more than 1 kW of cooling capacity make it suitable for many analytical instruments, lasers, vacuum systems, reaction equipment, and other laboratory systems requiring continuous liquid cooling.

Does this refurbished NESLAB Merlin M33 include a warranty?

Yes. This used Thermo Scientific NESLAB Merlin M33 is refurbished and tested by American Instrument Exchange and includes a 90-day warranty.

Testing Procedures for Used and Refurbished Laboratory Equipment

Ensure Accuracy, Safety, and Dependable Performance Across Applications

At American Instrument Exchange, all used and refurbished laboratory equipment undergoes a rigorous, multi-point testing protocol to ensure optimal performance, operational safety, and long-term reliability. Whether the equipment is destined for research, diagnostics, quality control, or production environments, our thorough inspection and testing process is designed to meet the highest standards of laboratory excellence.

Why Testing Used Lab Equipment Is Essential

Before any refurbished laboratory equipment is returned to service, it must be carefully tested to verify:

• Functional integrity and operational performance
• Setpoint accuracy and repeatability (where applicable)
• User interface responsiveness and control features

Proper testing reduces the risk of equipment failure, measurement inaccuracies, or user hazards—helping to ensure consistent results in clinical, academic, biotech, and industrial labs.

Our standardized lab equipment testing procedures are tailored to each equipment type, ensuring every unit meets manufacturer specifications and industry benchmarks.

Key Testing Procedures for Refurbished and Used Laboratory Equipment

1. Initial Visual Inspection

• Examine equipment housing for signs of wear, corrosion, or damage
• Check ports, power cords, and exterior components for tampering or deterioration
• Verify that internal and external parts (racks, shelves, connectors, accessories) are present and undamaged

2. Functional Startup and Operational Testing

• Power on the equipment and verify startup diagnostics
• Confirm functionality of displays, buttons, switches, and control panels
• Run basic functions to confirm proper response and behavior under standard operating conditions

3. Testing and Performance Verification

• Test internal sensors or control systems using industry-standard tools
• Perform operational tests to validate accuracy and consistency
• Verify key performance specifications such as temperature control, timing, speed, or measurement outputs, depending on equipment type

4. Mechanical and Electrical System Testing

• Evaluate motors, pumps, fans, or other moving parts for smooth operation
• Inspect and test wiring, relays, fuses, and circuit boards for safety and reliability
• Test power delivery and grounding compliance

5. Safety and Compliance Checks

• Ensure equipment is grounded and insulated to meet laboratory safety standards
• Test alarms, interlocks, emergency stops, or safety shutdown systems if applicable

6. Final Quality Assurance and Documentation

• Perform extended runtime testing
• Document operational logs, testing results, and any repairs or adjustments made
• Complete a final inspection, thorough cleaning, and packaging for delivery

Trusted Quality from American Instrument Exchange

With over 50 years of experience in laboratory equipment refurbishment, American Instrument Exchange is committed to delivering certified, lab-ready instruments backed by expert testing. Our testing protocols ensure that each piece of equipment—regardless of type—is safe, accurate, and dependable from day one.

Whether you're equipping a startup lab or expanding a high-throughput facility, you can count on our refurbished laboratory equipment to perform with precision and reliability.

Refurbishment Protocol for Used Laboratory Equipment from American Instrument Exchange

At American Instrument Exchange, every piece of used laboratory equipment we offer undergoes a multi-step refurbishment process. Whether it's an analytical balance, centrifuge, freezer, oven, or any other essential lab instrument, our goal is to restore each unit to peak performance—ensuring accuracy, safety, and long-term reliability in scientific, clinical, industrial, and academic environments.

Why Choose Refurbished Lab Equipment from American Instrument Exchange?

• Thoroughly tested for performance, precision, and safety
• Backed by a warranty
• A cost-effective alternative to new equipment
• Environmentally sustainable through equipment reuse and waste reduction
• Serviced by expert technicians with decades of laboratory equipment experience

Step-by-Step Refurbishment Protocol

Every instrument and system refurbished at American Instrument Exchange follows a detailed, industry-aligned process:

1. Initial Intake & Inspection

• Complete visual and structural inspection for cosmetic damage, wear, or corrosion
• Mechanical assessment of hinges, seals, fasteners, motors, and moving parts
• Missing components and damaged items are documented for repair or replacement

2. Cleaning and Decontamination

• Full internal and external cleaning using non-abrasive, lab-safe solutions
• Removal of biological, chemical, or particulate contamination
• Disassembly and cleaning of removable parts such as trays, shelves, and filters

3. Mechanical and Electrical Repair

• Replacement or repair of worn or broken mechanical parts
• Evaluation and servicing of control panels, sensors, switches, and displays
• Testing and repair of electrical wiring, fuses, circuit boards, and power supplies

4. Functional System Testing

• Assessment of all major functions specific to the equipment type (e.g., speed, temperature, force, weight, timing)
• Operation of control interfaces, programming menus, and digital displays
• Verification of stabilization time, responsiveness, and user input reliability

5. Testing and Performance Verification

• Testing of internal sensors, controllers, and measurement systems using certified tools
• Multi-point testing to ensure repeatability, accuracy, and performance consistency
• Confirmation of user-defined setpoints, timing sequences, or programmable cycles

6. Safety and Compliance Checks

• Testing of safety interlocks, alarms, and over-limit protection systems (as applicable)
• Electrical safety inspections, including grounding and insulation verification

7. Final Quality Assurance and Documentation

• Full operational testing under simulated lab conditions
• Completion of performance benchmarks, testing results, and repair logs
• Final cleaning and visual inspection

Trust the Experts at American Instrument Exchange

With over 50 years of experience in the laboratory equipment industry, American Instrument Exchange is a trusted leader in high-quality refurbished lab instruments. Our refurbishment protocols ensure that every piece of equipment we sell is lab-ready—offering the precision, performance, and durability your team can count on.

Whether you’re outfitting a new lab or expanding an existing operation, choose American Instrument Exchange for tested, warrantied, and cost-effective laboratory equipment.

Warranty Information

All used equipment sold by American Instrument Exchange is refurbished/reconditioned, tested to meet specifications, cleaned, and comes with a 90-day warranty from the date of shipment unless otherwise specified. New products include a warranty from the manufacturer. Your warranty is only valid if you have paid your invoice. If your invoice is over 30 days old, warranty work will not be performed until your invoice is paid in full. American Instrument Exchange is not liable for any special or consequential damages that result from the use of, or the inability to use, the materials on this site or the performance of the products,

Exceptions include international sales and items that are agreed to be sold with a lesser warranty or items that are agreed to be sold “as is.”

Should there be visible shipping damage to packaging or concealed shipping damage to item(s) supplied, buyer must communicate such damage to the delivering entity or carrier upon receipt first and to American Instrument the same day item is accepted / signed for. Failure to do so voids warranty. Customer decision to involve / procure third party or OEM service other than American Instrument or AIE assigned vendors to resolve in-warranty instrument failure or defect without first placing a service call to American Instrument voids warranty.

Return & Cancellation Policy

American Instrument Exchange will authorize the return of and issue a full refund for any equipment that is not working as represented and could not be replaced or repaired to the customer’s satisfaction by AIE or a representative of AIE during the warranty period. Returns without prior authorization and an RMA number will not be accepted.

Customers are responsible for proper packaging of the equipment and all included accessories. American Instrument will pay for insurance and shipping costs. Non-inventory items bought specifically to fill customer orders may possibly be returned, but on a case by case basis.

Customers who cancel orders after refurbishing has begun or after delivery where there are no equipment performance issues may be subject to a Restocking/Cancellation Fee of 20% or more and responsible for shipping costs for both the delivery and return.

Ongoing and Extended Support Options

American Instrument Exchange is able to provide additional repair and support services outside the warranty terms for most products that sell.

For biosafety cabinets, clean benches, chemical fume hoods, and other clean air products our team at AIE Laboratory Services can provide certifications, repairs, decontaminations, and other services for customers throughout New England, and guidance and limited technical assistance for any customers in the US and Canada for new or refurbished biosafety cabinets purchased from American Instrument Exchange.

For all other products, the repair service team at American Instrument Exchange can provide both field and depot repair evaluations. We can easily schedule and coordinate the pick-up and transportation of your malfunctioning equipment. By offering hourly rates lower than most OEM service providers and eliminating travel time for technicians, we help reduce repair costs. Furthermore, our lab depot repair service minimizes or eliminates scheduling delays. Our experienced service technicians are qualified to restore your equipment to factory specifications.

Please contact our team at info@americaninstrument.com for more details.

FAQ

Does the equipment come with a warranty?

Yes, all equipment from American Instrument Exchange comes with a warranty.
Used/reconditioned/refurbished equipment is tested to make sure it operates to the manufacturer's specifications and comes with a 90-day warranty (unless otherwise noted). New equipment comes with a warranty from the manufacturer.

How do you test and recondition the equipment?

Testing requirements vary across all the equipment categories we sell. Temperature controlled units are tested with NIST traceable probes and data loggers. Gaskets, external housing, glass, handles, controls and control screens are all thoroughly inspected for integrity and functionality.
We test all equipment using the manufacturer's parameters and specifications to confirm that the unit operates properly.

How do products ship from American Instrument Exchange?

We can ship products both nationally and internationally using a well-established network of transporters. Smaller items will ship via UPS. Larger equipment will be palletized and shipped either LTL or air-ride, depending on the specific equipment and/or delivery requirements.

Return and order cancellation policy

American Instrument Exchange will accept the return of any product that is not working as represented and could not be replaced or repaired to the customer's satisfaction during the warranty period. Customers who cancel orders after refurbishing has begun will be subject to a cancellation and restocking fee of between 20% and 40%.

Are discounts available for educational or non-profit institutions, or for bulk purchases?

Yes – call or email us today with a list of equipment you're looking for and we can potentially put together a quote that includes a discount.

How does your price matching policy work?

We strive to keep our pricing competitive and reasonable. If you find comparable items for sale at a lower price from other vendors please send us a link and or quote for the item and we'll do our best to match or beat the price.

Can I see the equipment in person before committing to a purchase?

Customers are welcome to make an appointment to view equipment in our warehouse. Given our workload we may not be able to test or clean the equipment prior to your arrival if you have not committed to an order.

1023 Western Avenue is a working warehouse, not a showroom, and customers should dress appropriately and wear closed toe shoes.

Can I ship products that I purchased elsewhere to American Instrument for repair?

Yes – please see our repair services page for more information.