Vapor Degreaser Equipment and Ultrasonic Vapor Degreasers

If you’ve ever been wearing glasses as you walked into an air-conditioned building on a hot summer day, you already have a good understanding of part of how the vapor degreaser process works. (For those in colder climates, walking outside while wearing glasses on a cold winter day is an even better example.)

So, how does a vapor degreaser work? The vapor degreasing process is a cleaning process that uses solvent vapors (boiled solvent) rather than water to clean parts.

A vapor degreaser has two tanks (sumps) of solvent inside. One vapor degreasing tank boils the solvent (boil sump) which creates a vapor or mist of the solvent. The second sump (rinse sump) is heated but not to the boiling point and is used as the second cleaning stage. The vapor degreaser also has bands of cooling coils inside just above the level of the sumps. These coils cause the vapor to return to a liquid state and fall back into the sump. The effect is like small “clouds” of the solvent are formed between the top of the sumps and the cooling tubes.

As parts at room temperature are lowered through the cooling area into the vapor, the vapor from the boil sump condenses on the parts just like moisture in the air does on your glasses in the examples above. This condensation contains the solvent that dissolves the oils on your parts, and the beading action creates droplets which run across the surfaces of the parts and fall back into the boil sump. The parts are then moved to the ultrasonic sump which contains heated but non-boiling solvent. This allows the parts to be lowered into the sump so that any blind holes or internal features are also thoroughly exposed to the solvent.

Finally parts are raised into the cooling coil area to allow the solvent to quickly dry and then raised through a second layer of freeboard coils near the very top of the vapor degreaser that insure complete drying and the recapture of the solvent from the parts.

As the clock runs out on the 3M™ Novec™ phaseout, many manufacturers are wondering how to switch their vapor degreasers to a 3M™ Novec™ replacement solvent such as BestSolv® Engineered Fluids.

Here are the steps to use when converting your vapor degreaser to a new solvent.

Remove Old Solvent

Completely remove the old solvent from the vapor degreaser before adding the new solvent. Any residual old solvent left in the lines may be flushed with the new solvent. Do NOT use water to clean the vapor degreaser or flush the lines. If residual old solvent remains or has turned acid previously, neutralize the degreaser and all surfaces.

Add New Solvent

Review the Safety Data Sheet for the new solvent prior to first use. As always when handling solvents, use appropriate protective equipment as mentioned in the Safety Data Sheet. Since most solvents are designed to evaporate quickly, be careful not to leave the solvent container open any longer than necessary.

Identify Boiling Point of New Solvent

The boiling point on your new solvent may be different from that of the old solvent. Vapor degreaser settings are based on the boiling point of the solvent used, and should be adjusted when a new solvent is used in the degreaser.

Use the Safety Data Sheet, Technical Data Sheet, or other publicly available source to identify the boiling point of the new solvent. For BestSolv® Engineered Fluids, you can find this information through our Technical Data Sheets page.

Adjust Vapor Degreaser Settings

Use the new solvent’s boiling point as a reference for changing the following settings on your vapor degreaser:

For example, a solvent with a boiling point of 165 °F would have a Vapor Up Control (TH-1) set point of 155 °F (165 – 10 = 155).

That’s it! Your vapor degreaser is ready to return to precision cleaning with your new solvent.

NOTE: Vapor degreaser controls differ by manufacturer. Some may not contain all of the settings described.

For further information about vapor degreaser settings, see the reference section below.

Vapor Degreaser Settings Reference

• Liquid Temperature Control (LTC): Set 7-10 °F above the boiling point of the solvent being used. A 10 °F rise in the boiling point indicates that the boiling sump has accumulated the equivalent oil solution of approximately 30% by weight, along with any other contaminants. Boil down and addition of fresh solvent is recommended.
• High Temperature Control (HTC): Set 10-15 °F above the boiling point of the solvent being used. A 10 °F rise in the boiling point indicates that the boiling sump has accumulated the equivalent oil solution of approximately 30% by weight, along with any other contaminants. Continued operation may be hazardous.
• Low Level Control (LLC): A safety to turn the heat off if the liquid level falls below a safe level.
• Refrigeration Control (RT): Regulates the temperature of the cooling coils. Typically set at 45-50 °F. It is not necessary to change this setting when changing solvents.
• Solvent Vapor Control (SVC): Turns off the heat in the event of high vapor level and must be set at 10 °F below the boiling point of the solvent being used.
• Vapor Up Control (TH-1): Turns on an indicator light when the solvent vapors are up to proper level on the cooling coils. This indicates the equipment is ready to operate. It also inhibits the spray pump(s) when the vapor line is below the normal operating level. The proper temperature setting is 10 °F below the boiling point of the solvent being used.

Manufacturers replacing 3M™ Novec™ or methylene chloride have three main options:

• Drop-in replacements – Engineered fluids that are molecularly identical to Novec™ solvents, allowing processes to continue with little or no revalidation.
• Similar molecule blends – Use a different molecule than 3M™ Novec™ but offer similar properties, at a lower price point.
• PFAS-free alternatives – New solvent formulations that provide strong cleaning performance while meeting the strictest regulatory standards domestically and worldwide.

BestSolv® Engineered Fluids cover each of these categories, helping manufacturers maintain continuity today while preparing for long-term compliance.

Our role goes beyond supplying solvent choices. We guide you through revalidation and material compatibility so you can move forward with confidence. We know how critical process continuity is in mission-driven industries, and we are committed to being a trusted technical partner in your transition.

While vapor degreasing solvents are compatible with metals, plastics and elastomers can react differently. Some may show changes such as surface stress, brittleness, or swelling, depending on the material. Because performance varies, it’s best to test any new solvent with your specific plastics and elastomers to confirm compatibility. Reach out today to one of our Chemical Team members for detailed compatibility information.

Safety and compliance are top priorities when selecting a vapor degreasing solvent. Here are the key considerations:

• Worker Safety: Some legacy solvents, such as methylene chloride and trichloroethylene (TCE), carry significant health hazards and are subject to strict workplace exposure limits. Modern options like BestSolv® Engineered Fluids are nonflammable and designed with lower toxicity profiles to help reduce operator risk.
• Environmental Regulations: With ongoing updates to EPA and EU REACH standards, including measures to reduce high-GWP and PFAS-containing solvents, the need for compliant alternatives grows. BestSolv® fluids, including PFAS-free options, are formulated to align with these evolving regulations while maintaining strong cleaning performance.
• Process Compliance: Aerospace, medical device, and electronics industries require solvents that can pass audits and validation testing. BestSolv® fluids support validated processes.
• Sustainability & Emissions Control: Modern degreasing fluids and solvents are designed for closed-loop recovery systems, minimizing emissions and solvent loss, which reduces both environmental impact and operating costs.

For detailed information on handling, exposure limits, and other safety measures for BestSolv® fluids, please refer to the Safety Data Sheet (SDS) for each fluid.

Selecting a solvent is not just about performance today—it’s about ensuring reliability and supply continuity for years to come. Here are the key factors to consider:

• Supply Chain Stability: Many companies single-sourced their legacy 3M™ Novec™ fluids, creating major vulnerabilities when supply ended. BestSolv® fluids are dual-sourced, giving manufacturers consistent, reliable access to the solvents they need without the risk of disruption. 

• Validation Requirements: Aerospace, medical device, and electronics industries demand extensive revalidation when switching chemistries. BestSolv® offers exact molecular replacements (minimizing requalification), as well as cost-effective similar molecule fluids and PFAS-free fluid options as sustainable alternatives. 

• Performance & Compatibility: The right solvent must deliver effective cleaning, material compatibility, and process efficiency. Our team partners with you to review your soils, materials, and equipment, helping ensure your solvent choice is well-suited for both current and future needs.

At Best Technology, we help you look beyond the immediate change to make a solvent choice that protects your operations and delivers confidence in the long term.

BestSolv® Engineered Fluids do not turn acidic on their own because they contain no water. If your solvent appears cloudy, discolored, or shows unusual behavior, it usually indicates that water or contaminants, such as particulates or metal shavings, are entering the vapor degreaser from an external source.

• Test the pH of the solvent

• Common Contamination Intrusion:
  • Water-based oils or fluids
  • Coil condensation Temperature
  • Cooling system leaks
  • Water Separator Issues
  • Metal particulate build-up in the tank

If your vapor degreaser becomes acidic, address it promptly to prevent corrosion of joints, welds, and other components.

At Best Technology, we help customers troubleshoot issues like this to maintain solvent integrity, process reliability, and audit readiness. If you suspect contamination, our team can walk you through step-by-step checks or recommend further testing to keep your system running safely and efficiently.

BestSolv® Engineered Fluids are stable and do not require stabilizer additives, unlike older solvents such as n-propyl bromide (nPB). However, regular equipment maintenance is essential to protect solvent integrity and ensure consistent cleaning performance. Key best practices include:

• Regular maintenance of water sump (boil sump / water separator)
• Preventing microbial growth
• Refrigerant / cooling system checks
• Sludge removal

Maintaining your vapor degreasing system on this schedule helps prevent unnecessary solvent disposal, reduces operating costs, and ensures consistent, validated cleaning performance.

At Best Technology, we partner with customers not only to supply high-quality solvents but also to guide equipment care and troubleshooting, helping you extend fluid life and protect your critical processes.

Some soils, such as no-clean fluxes, heavy machining oils, or baked-on residues, are too stubborn for a single-solvent vapor degreaser. In these cases, co-solvent or bi-solvent processes can provide the cleaning power needed:

• Co-Solvent Process: Uses a blend of a solvating agent and a fluorocarbon rinse agent. Parts are immersed in a boiling sump with the blended co-solvent to dissolve soils, then rinsed in a separate sump with pure, distilled fluorocarbon to remove any remaining contaminants, and finally dried in the degreaser’s vapor zone. This ensures strong cleaning action while leaving a residue-free, fast-drying finish.
• Bi-Solvent Process: Cleans difficult soils by using two different solvents in a three-step process: a preliminary soak in heated solvent for initial cleaning, followed by a vapor rinse in a traditional two-sump degreaser using a different, lower-boiling point solvent, and finally drying the parts in the degreaser’s vapor zone.
• Key Benefits: Both approaches deliver enhanced solvency for tough soils while maintaining the safety, nonflammability, and low-emission advantages of vapor degreasing.

To learn more about bi-solvent or co-solvent processes, see our page Bi-Solvent and Co-Solvent Vapor Degreasers.

At Best Technology, our engineers help you evaluate whether a co-solvent or bi-solvent process is the right fit, and guide you through validation so your cleaning system stays effective and efficient.

Cleaning and drying efficiency in vapor degreasing can be significantly improved by several process adjustments:

• Fixturing & Basket Design: Use open, properly spaced baskets or racks to avoid shadowing and allow vapors to reach all surfaces. Avoid stacking parts too tightly. 
• Dwell Time: Ensure parts remain in the vapor zone long enough for full condensation and rinse—but not so long that excess solvent re-condenses inside cavities. 
• Ultrasonics: Adding ultrasonics can dislodge particles and assist in cleaning blind holes, threads, and complex geometries. 
• Vapor Line Control: Maintaining a stable vapor line with well-calibrated cooling coils prevents solvent carry-over and ensures consistent drying. 
• Drying Efficiency: Slow removal of parts from the vapor zone allows complete evaporation and minimizes spotting or retained solvent.

BestSolv® Engineered Fluids are formulated with low surface tension and fast evaporation rates, which support thorough cleaning and rapid, residue-free drying.

At Best Technology, we help manufacturers fine-tune both chemistry and equipment settings so every part—from precision aerospace assemblies to medical implants—comes out clean, dry, and ready for use or further processing.

Cleanliness validation is essential in industries where performance and safety depend on residue-free parts. Here are the most common methods:

• Gravimetric Testing: Weighing parts before and after cleaning to measure the total nonvolatile residue (NVR) left behind.
• FTIR Analysis: Using infrared spectroscopy to detect organic residues at trace levels.
• Water Break Test: Ensuring no hydrophobic films remain by checking how water sheets or beads on a surface.
• Dyne Testing: Measuring surface energy to confirm readiness for coatings, adhesives, or bonding.
• SIR (Surface Insulation Resistance): Common in electronics to confirm that no ionic residues remain that could lead to conductivity issues.

BestSolv® Engineered Fluids are designed for high solvency and fast drying, making them ideal for meeting these validation standards.

At Best Technology, we don’t just supply the solvent — we work with you to ensure your parts consistently meet the standards required for aerospace, medical device, and electronics manufacturing.

Desiccants are used to absorb the water found in humid conditions to reduce or eliminate condensation. It can also be added directly to liquids to absorb the water content from the fluid.  We are used to seeing the small white bags of desiccant found in packaging for everything from shoes to electronic equipment.  Most of this desiccant is silica – typically in gel form.  Other common substances used as desiccants are activated charcoal and calcium chloride.

The desiccant used in vapor degreasers is 3 Angstrom Molecular Sieve, small pellets of zeolite clay. Like all desiccants, the zeolite clay adsorbs water from the solvent, and may be reused by baking it dry. Desiccants are most often used in a vapor degreaser if the solvent contains an alcohol. This is often the case with solvents used for defluxing processes on soldered boards and leads. Water found in the separator extracts the alcohol from the solvent and in turn the water and alcohol are absorbed by the zeolite clay. If a degreaser is operated in a very humid environment, a desiccant may be needed to effectively remove the water from the solvent.

Complex part geometries can trap solvent, leading to spotting, residues, or longer cycle times. To improve drying and ensure parts are ready for use, consider these adjustments:

• Part Orientation: Angle parts to encourage solvent drainage from blind holes, threads, or capillaries. Vertical orientation often allows vapors and condensate to escape more efficiently.
• Basket & Fixture Design: Use open, perforated fixtures that allow free vapor circulation. Avoid designs that trap liquid in pockets or shield vapor flow.
• Withdrawal Speed: Raise parts slowly through the vapor zone so condensation has time to evaporate, minimizing solvent retention and spotting.
• Ultrasonics & Agitation: Gentle ultrasonics or controlled agitation help release solvent and contaminants from intricate features.
• Secondary Drying Aids: Warm nitrogen blow-off, vacuum drying, or extended dwell time above the vapor line can be used for especially challenging geometries.

BestSolv® Engineered Fluids are formulated with low surface tension and high volatility, allowing them to wick into—and then quickly evaporate from—tight spaces.

At Best Technology, we work with you to evaluate part design and solvent choice so your process delivers clean, dry, and validation-ready parts, even for the most complex assemblies.

Minimizing solvent consumption lowers operating costs and reduces environmental impact. Key strategies include:

• Modern Equipment Design: New vapor degreasers use secondary cooling coils, freeboard extensions, and sliding covers to capture vapors and cut solvent loss.

• Closed-Loop Recovery: Many systems are engineered for continuous solvent distillation and recycling, reducing waste and keeping emissions low.

• Optimized Loading Practices: Proper basket design and avoiding fast motion of parts when transferring loads reduces drag-out and improves efficiency.

• Reduce or Eliminate Air Flows: Air movement such as HVAC returns, draft hoods and air vents can act like a chimney, pulling solvent vapors out of the degreaser.

• Maintenance & Monitoring: Regular checks of seals and gaskets help maintain efficiency and extend fluid life.

To learn more about reducing solvent loss, see our page How to Minimize Solvent Losses from Vapor Degreasers.

At Best Technology, we not only supply fluids but also help you optimize equipment, processes, and solvent choice to achieve the lowest possible emissions without sacrificing cleaning performance.