Condensate Treatment & Product Selection
Compare Quincy QOCS and Atlas Copco OSC oil-water separators by system airflow, operating conditions and filtration media. Then distinguish condensate treatment from upstream water separation and drainage.
Start With the Correct Product Type
These components solve different problems and are installed at different points in a compressed air system.
Treats discharged condensate
Receives oily condensate collected from compressors, receivers, filters and dryers. Its filtration media captures oil so the remaining water can be handled according to applicable disposal requirements.
Removes bulk liquid from air
Removes entrained liquid water from the compressed-air stream before it reaches downstream equipment. Atlas Copco WSD separators are not substitutes for oil-water condensate treatment.
Automatically discharges liquid
Discharges collected condensate from a compressor, receiver, separator, filter or dryer. The discharged liquid may still require treatment by an oil-water separator.
Quick Selection Tool
Enter the total compressor capacity and select the climate. The tool applies the published Quincy climate correction factors and recommends the first QOCS/OSC capacity band that meets the corrected requirement.
Planning estimate: Confirm final sizing against the current manufacturer data, compressor type, lubricant, humidity, temperature, operating hours and local discharge requirements.
Your corrected requirement is 100 CFM. Select a nominal capacity of at least 106 CFM.
Quincy and Atlas Copco
The capacity comparison below uses the manufacturers' published mild-climate ratings with dryers and filtration. Match capacity first, then verify the operating correction factors.
| Capacity band | Quincy QOCS | Atlas Copco OSC | Condensate inlet | Water outlet |
|---|---|---|---|---|
| 25 CFM | QOCS 25 | OSC 12 CLAY | 1/4 in. | 3/8 in. |
| 53 CFM | QOCS 53 | OSC 25 CLAY | 1/4 in. | 3/8 in. |
| 106 CFM | QOCS 106 | OSC 50 CLAY | 2 × 1/2 in. | 1/2 in. |
| 180 CFM | QOCS 180 | OSC 85 CLAY | 2 × 1/2 in. | 1/2 in. |
| 360 CFM | QOCS 360 | OSC 170 CLAY | 2 × 3/4 in. | 3/4 in. |
| 636 CFM | QOCS 636 | OSC 300 CLAY | 2 × 3/4 in. | 3/4 in. |
| Approximately 1,325 CFM | QOCS 1325* | OSC 625 CLAY | 2 × 3/4 in. | 3/4 in. |
| Approximately 2,650 CFM | QOCS 2650* | OSC 1250 CLAY | 2 × 3/4 in. | 3/4 in. |
| Approximately 5,300 CFM | QOCS 5300* | OSC 2500 CLAY | Up to 4 × 3/4 in. | Up to 2 × 3/4 in. |
*QOCS 1325, 2650 and 5300 are shown in the manufacturer capacity table but were not present in the current online accessory assortment supplied for this guide.
Available Online
Compare the currently available Quincy QOCS and Atlas Copco OSC models by capacity, then open the product page for current price and availability.
Q
CFM capacity band
CFM capacity band
CFM capacity band
CFM capacity band
CFM capacity band
CFM capacity band
A
CFM with dryer and filters
CFM with dryer and filters
CFM with dryer and filters
CFM with dryer and filters
CFM with dryer and filters
CFM with dryer and filters
CFM with dryer and filters
CFM with dryer and filters
CFM with dryer and filters
Sizing Conditions
Separator capacity is affected by the volume of condensate and oil load entering the unit. A nameplate CFM match is not always sufficient.
Quincy correction factors
Divide system CFM by the applicable factor to estimate the required nominal capacity.
Atlas Copco reference conditions
Higher humidity, temperature or daily operating hours can reduce effective capacity.
Filtration media
Standard multi-stage systems use polypropylene with final polishing media. Atlas Copco describes activated carbon for a broad range of oils and organoclay options for stronger emulsions.
Discharge requirements vary. Both brochures describe outlet oil content as low as approximately 5 ppm under applicable conditions, but local wastewater rules and permit requirements determine whether and how treated water may be discharged.
Complete the Condensate Path
A water separator removes bulk liquid from the compressed-air stream. A condensate drain moves that liquid out of the equipment. An oil-water separator then treats the discharged condensate.
Technical Review & Sources
This guide was reviewed by the AirCompressors.com Air Expert Insights Team and last updated September 16, 2026. Capacity bands, connection sizes, operating conditions and service guidance were compiled from current manufacturer product literature supplied for the Quincy QOCS and Atlas Copco OSC product families.
Specification notice: Manufacturer ratings can change. Confirm final sizing, connection dimensions, lubricant compatibility and discharge requirements against the current product data sheet before purchase or installation.
Frequently Asked Questions
Our compressed-air specialists can help you compare separator capacity, filtration media, operating conditions and installation requirements.