Neslab Merlin M25 circulator

Brand : Neslab

Product Code : SKU 1486B CIRC

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Thermo Scientific NESLAB Merlin M25 Recirculating Chiller

The Thermo Scientific NESLAB Merlin M25 Recirculating Chiller is a compact laboratory cooling system designed to provide reliable closed-loop temperature control for analytical instruments, lasers, research equipment, condensers, and other heat-generating laboratory systems. With a -15°C to +35°C setpoint range, approximately ±0.1°C temperature stability, 741 W of cooling capacity at +20°C, and a compact 1.8 L reservoir, the Merlin M25 provides substantial cooling performance in a relatively small footprint.

Designed specifically for external equipment cooling, the Merlin M25 combines mechanical refrigeration, a plate heat exchanger, recirculating pump, polyethylene reservoir, and microprocessor temperature controller in a self-contained system. Its closed-loop design allows laboratories to maintain consistent coolant temperature while reducing or eliminating dependence on continuous tap-water cooling.

Available used and refurbished from American Instrument Exchange, this NESLAB Merlin M25 is inspected and tested for reliable refrigeration, circulation, temperature regulation, and controller performance. A 90-day warranty is included.

Key Features

-15°C to +35°C setpoint temperature range
Approximately ±0.1°C temperature stability
741 W cooling capacity at +20°C
Approximately 2,528 BTU/hr cooling capacity at +20°C
Compact 1.8 L reservoir
Integrated mechanical refrigeration
R134a refrigerant
Closed-loop external circulation
Microprocessor temperature controller
Plate heat exchanger
Positive-displacement pump configuration
Air-cooled refrigeration system
Pulse-width-modulated refrigeration control
Designed to reduce compressor cycling
Suitable for analytical instruments and laboratory equipment
115 V, 60 Hz configurations available
Used, refurbished, and tested by American Instrument Exchange
90-day warranty included

Overview

The NESLAB Merlin M25 is the compact entry in the Merlin family of dedicated recirculating chillers. Rather than functioning as an open circulating water bath, the M25 is designed primarily to provide temperature-controlled coolant to compatible external laboratory and technical equipment.

Coolant is pumped from the Merlin through the connected equipment, where it absorbs process heat. The warmed fluid then returns to the M25, where an integrated refrigeration system and plate heat exchanger remove the accumulated heat before the fluid is recirculated.

This closed-loop arrangement provides several advantages over once-through facility water. Coolant is reused rather than continuously discharged, temperature can be controlled independently of seasonal tap-water conditions, and the laboratory gains a dedicated cooling source for sensitive equipment.

The Merlin M25 also uses a microprocessor-based temperature controller and modulated refrigeration control rather than relying entirely on repetitive compressor on/off cycling. This helps the system respond to changing cooling loads while maintaining stable coolant conditions.

Key Specifications

Specification	Details
Manufacturer	Thermo Scientific / NESLAB
Series	Merlin
Model	M25
Equipment Type	Refrigerated recirculating chiller
Setpoint Temperature Range	-15°C to +35°C
Ambient Operating Range	+10°C to +35°C
Temperature Stability	±0.1°C
Cooling Capacity at +20°C, 60 Hz	741 W
Cooling Capacity at +20°C	Approx. 2,528 BTU/hr
Reservoir Capacity	1.8 L / 0.5 gal
Refrigerant	R134a
Refrigeration	Air-cooled
Heat Exchanger	Plate type
Temperature Controller	Microprocessor
Circulation	Closed-loop external circulation
Pump	Positive-displacement; verify installed configuration
Dimensions	Approx. 12.6 in. W × 20.9 in. D × 23.5 in. H
Weight	Approx. 118 lb, configuration dependent
Electrical	115 V, 60 Hz available; verify unit nameplate
Warranty	90 days

Common Applications

The NESLAB Merlin M25 is suitable for laboratory and technical applications requiring continuous removal of moderate heat loads. Common uses include analytical instrument cooling, laser cooling, condenser cooling, vacuum equipment, spectroscopy systems, semiconductor equipment, medical equipment, small reaction systems, imaging equipment, and other devices designed for an external liquid-cooling loop.

Its approximately 741 W cooling capacity makes the M25 particularly useful as a dedicated chiller for individual laboratory instruments.

The Merlin M25 can also replace once-through tap-water cooling in compatible applications. Instead of continually drawing fresh water and discharging it to a drain, the Merlin recirculates the same heat-transfer fluid through the equipment and refrigeration system.

This can substantially reduce water consumption while providing more consistent coolant temperature.

Ideal Laboratory Types

The NESLAB Merlin M25 is well suited for biotechnology facilities, pharmaceutical laboratories, analytical laboratories, chemistry research groups, medical research facilities, materials-science laboratories, semiconductor research environments, laser laboratories, industrial R&D departments, and academic research facilities.

Its compact footprint is particularly useful when a dedicated chiller is needed for one analytical instrument or experimental system.

The M25 may also be an attractive replacement for laboratories already operating equipment originally configured around NESLAB or Thermo Scientific Merlin chillers.

Cooling Performance & Temperature Stability

The NESLAB Merlin M25 provides a setpoint range of approximately -15°C to +35°C with temperature stability of approximately ±0.1°C.

At a +20°C process temperature, Thermo Scientific specifies approximately 741 W of cooling capacity, equivalent to approximately 2,528 BTU/hr.

These performance figures are based on defined test conditions. Manufacturer specifications were obtained using a 50/50 ethylene glycol/water mixture at a +20°C process setpoint and +20°C ambient temperature at nominal operating voltage.

Actual cooling performance can change with process temperature, ambient temperature, heat-transfer fluid, altitude, voltage, pump configuration, and external hydraulic resistance.

This is especially important at subambient temperatures. Cooling capacity generally decreases as the required coolant temperature falls, so the 741 W figure at +20°C should not be interpreted as 741 W of available cooling throughout the entire -15°C to +35°C range.

For demanding applications, chiller selection should therefore be based on the required heat-removal capacity at the actual intended coolant temperature.

Circulation & Pump Performance

The NESLAB Merlin M25 was available with a positive-displacement circulation pump designed to provide reliable coolant flow through external equipment.

Positive-displacement pumping can be particularly useful when coolant must pass through equipment with restrictive internal passages or other significant hydraulic resistance.

Actual circulation performance depends on the pump installed in the individual M25 as well as tubing diameter, tubing length, fittings, coolant viscosity, operating temperature, elevation, and restrictions within the connected equipment.

Because pump configuration can affect both flow characteristics and chiller performance, customers requiring a specific minimum flow or pressure should provide those requirements before purchase.

American Instrument Exchange can evaluate the individual M25 configuration and help determine whether it is appropriate for the intended cooling circuit.

Refrigeration & Control System

The Merlin M25 uses an air-cooled mechanical refrigeration system with R134a refrigerant.

A plate heat exchanger transfers heat from the circulating process fluid to the refrigeration system, while the microprocessor controller regulates coolant temperature.

The Merlin design uses a pulse-width-modulated valve to adjust refrigeration in response to cooling demand. Instead of relying solely on repeated compressor starts and stops, the system can modulate refrigeration according to the amount of heat being removed from the process.

This approach supports stable temperature control while reducing unnecessary compressor cycling.

Adequate ventilation around the chiller remains important because heat removed from the connected equipment is ultimately rejected into the surrounding room through the air-cooled condenser.

Refurbishment & Testing

This used Thermo Scientific NESLAB Merlin M25 Recirculating Chiller is refurbished and tested by American Instrument Exchange before shipment. Our technicians inspect the compressor, condenser, refrigeration circuit, plate heat exchanger, circulation pump, reservoir, microprocessor controller, display, fluid connections, electrical components, housing, and applicable safety systems.

Temperature-controlled equipment is tested using NIST-traceable probes and data loggers. The Merlin M25 is operated under simulated laboratory conditions to evaluate temperature pull-down, refrigeration performance, circulation, temperature regulation, controller operation, and overall system reliability.

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

Customers requiring the Merlin M25 for a particular instrument or process are encouraged to provide the desired coolant temperature, approximate heat load, minimum flow, pressure requirements, and intended heat-transfer fluid. 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 M25.

Choosing the Right Recirculating Chiller

The NESLAB Merlin M25 is particularly well suited for laboratories that need a compact dedicated chiller for moderate heat loads.

Its approximately 741 W cooling capacity at +20°C places it well above small 200–300 W benchtop chillers while remaining substantially smaller than multi-kilowatt process cooling systems.

The -15°C lower setpoint also provides flexibility for applications requiring coolant below the freezing point of water, provided an appropriate heat-transfer fluid is used.

Cooling capacity is only one part of chiller selection. Buyers should also consider required coolant temperature, temperature stability, pump flow and pressure, external circuit resistance, fluid compatibility, ambient conditions, and electrical service.

For an analytical instrument, the manufacturer's required coolant specifications are particularly valuable. Matching both the heat load and circulation requirements can prevent insufficient cooling or inadequate fluid flow.

American Instrument Exchange can help compare available used and refurbished recirculating chillers based on these requirements.

Related Equipment

American Instrument Exchange stocks a range of laboratory circulators, including Thermo Scientific and NESLAB recirculating chillers, refrigerated/heated circulators, immersion coolers, and process temperature-control systems. Laboratories considering the Merlin M25 may also want to compare available laboratory water baths, reactors and fermenters, evaporators and extractors, and other refurbished laboratory equipment.

NESLAB Merlin M25 Frequently Asked Questions

What is the temperature range of the NESLAB Merlin M25?

Thermo Scientific specifies a setpoint temperature range of approximately -15°C to +35°C. Subzero operation requires an appropriate heat-transfer fluid rather than plain water.

How stable is the Merlin M25?

The manufacturer specifies temperature stability of approximately ±0.1°C.

How much cooling capacity does the Merlin M25 provide?

The M25 provides approximately 741 W, or 2,528 BTU/hr, of cooling capacity at a +20°C process temperature under specified test conditions.

What is the reservoir capacity?

The Merlin M25 has an approximately 1.8 L, or 0.5 gal, internal coolant reservoir.

What refrigerant does the Merlin M25 use?

The M25 uses R134a refrigerant.

Can the Merlin M25 replace laboratory tap-water cooling?

For compatible equipment within its cooling and circulation capabilities, yes. Its closed-loop design continuously recirculates coolant rather than consuming fresh water during operation.

Can the Merlin M25 operate below 0°C?

Yes. Its setpoint range extends to approximately -15°C. An appropriate glycol/water mixture or other manufacturer-compatible heat-transfer fluid must be used for subzero operation.

Is the Merlin M25 a water bath?

No. The M25 is primarily a closed-loop recirculating chiller designed to provide coolant to external equipment rather than an open bath intended for direct sample immersion.

What information should I provide when determining whether an M25 will cool my instrument?

The most useful information includes the required coolant temperature, estimated heat load, minimum flow rate, pressure requirements, coolant specification, and electrical requirements of the installation.

Does this refurbished NESLAB Merlin M25 include a warranty?

Yes. This used NESLAB Merlin M25 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.

Sku 1486b circ Open