The Castair AC150 Free Standing Aftercooler handles 150 CFM of compressed air discharge from your compressor before it ever reaches the receiver tank. This is the correct aftercooler for 40–50 HP compressor systems — the class of machine that typically serves busy multi-bay auto repair shops, body shops running two spray booths simultaneously, fleet maintenance yards, and light industrial operations where compressed air runs continuously through the shift. If your compressor is putting out 120–150 CFM and you are dealing with wet air, excessive tank condensate, or dryer performance problems, the AC150 is the direct solution.
Hot compressed air — typically 250–350°F at the pump discharge — carries a full load of water vapor in suspension. The moment that air cools, the vapor condenses into liquid water. Where that cooling happens determines where the water ends up. Without an aftercooler, the cooling happens in your receiver tank and downstream air piping — which means water ends up everywhere: in your filters, your tools, your spray equipment, and your refrigerated dryer. With the AC150 in place, the cooling and condensation happen in the aftercooler's heat exchanger, right at the source, before the air enters the tank. One drain point. The rest of the system stays dry.
Why This Equipment Matters Before You Choose Anything Else
Shops invest in refrigerated air dryers to get dry air. The problem: refrigerated dryers are sized and rated for inlet air at or near 70–100°F. When your compressor discharges at 300°F and the tank cools that to 120°F, your dryer is receiving air that is 50°F hotter than its rated inlet condition. It cannot pull moisture out fast enough. The aftercooler fixes that — it brings the air down to within 15°F of ambient before it enters the tank, so the dryer receives air it was designed to handle. Adding an aftercooler to an existing dryer installation often fixes a wet air problem that the dryer alone could not solve.
Key Features of the AC150 Aftercooler
- 150 CFM Capacity: Rated for compressor systems producing up to 150 CFM — covers 40–50 HP two-stage reciprocating and equivalent rotary screw compressors
- 250 PSIG Maximum Pressure: Full pressure compatibility with two-stage reciprocating and industrial rotary screw compressors
- 350°F Maximum Inlet Air Temperature: Built to handle the full discharge temperature range of industrial compressor pumps without degraded performance
- Cools to Within 15°F of Ambient: Brings compressed air from 250–350°F pump discharge down to within 15 degrees of your shop air temperature — critical for downstream dryer and filter effectiveness
- 65% Total Moisture Removal: Removes approximately 65% of the water vapor load from the compressed air stream at the source, before the receiver tank — every 20-degree temperature drop removes 50% of remaining moisture
- 1-1/2 inch NPT Ports: Standard NPT inlet and outlet connections for direct integration into discharge piping
- Fan-Cooled Heat Exchanger: Electric fan pulls ambient air across the heat exchanger core — no water line required, no water treatment, no freeze risk in the cooling circuit itself
- 115V / 1-Phase / 60 Hz Power: Standard single-phase power supply for the cooling fan motor
- Floor or Suspended Mounting: Install on the floor alongside the compressor, or suspend overhead to keep the floor clear
- Horizontal or Vertical Air Flow: Air flow orientation is configurable to match your installation layout
- Dimensions: 43.5 inches H x 14.75 inches W x 46.5 inches D
- Weight: 145 lbs
- Minnesota Manufacturing: Castair builds to industrial-grade standards in Minnesota — these are not import units engineered to a price point
What is in the Box
- Castair AC150 free standing aftercooler unit
- Fan assembly and motor (pre-installed)
- 1-1/2 inch NPT inlet and outlet fittings
- Mounting hardware for floor installation
- Installation documentation
Optional accessories available separately: filter with automatic drain, temperature control valve #86816.
Available Configurations — Full Castair Free Standing Aftercooler Lineup
The AC150 sits near the top of the Castair free standing aftercooler range. Match your aftercooler to your compressor's actual CFM output:
- FSAC35: 35 CFM, 3/4 inch NPT — 5–7.5 HP compressors
- FSAC50: 50 CFM, 1 inch NPT — 7.5–10 HP compressors
- FSAC75: 75 CFM, 1 inch NPT — 10–15 HP compressors
- FSAC100: 100 CFM, 1-1/4 inch NPT — 15–25 HP compressors
- AC120: 120 CFM, 1-1/2 inch NPT — 25–40 HP compressors
- AC150: 150 CFM, 1-1/2 inch NPT — 40–50 HP compressors (this unit)
- AC240: 240 CFM, 2 inch NPT — 50–75 HP industrial compressors
- AC300: 300 CFM, 2 inch NPT — 75–100 HP large industrial systems
All models: 250 PSIG maximum, 350°F maximum inlet, cools to within 15°F of ambient, 65% water removal at 250°F inlet. Contact us if you are unsure which size matches your compressor.
Belt Guard Style Aftercoolers — For Lower-CFM Compressors
For compressors under 100 CFM, Castair offers belt guard-mounted aftercoolers that replace the belt guard entirely — compact, no additional floor footprint:
- BGAC1: 35 CFM
- BGAC2: 50 CFM
- BGAC3: 75 CFM
- BGAC4: 100 CFM
At 150 CFM, you need the AC150 free standing unit — the belt guard series does not go to this capacity.
When Does a Shop Need the AC150?
The AC150 is sized for the 40–50 HP compressor range. Shops in this tier are running serious air demands:
- Collision repair and body shops with two or more spray booths — at this volume, wet air is not just an annoyance, it is a direct cost in rework and material waste
- Busy multi-bay auto repair shops with 5–8 lifts running simultaneously and continuous impact wrench, air ratchet, and tire machine use
- Fleet maintenance operations running multiple service bays simultaneously through a full shift
- Light manufacturing with pneumatic tooling, air-actuated clamping, and material handling systems that cannot tolerate moisture contamination
- Operations with refrigerated air dryer problems — if your dryer is not keeping up, add the aftercooler upstream first before blaming the dryer
If your compressor produces under 120 CFM, step down to the AC120. If your system runs above 150 CFM — large industrial compressors, multiple machines on a header — step up to the AC240 or AC300.
Technical Specifications
- Model: AC150
- Manufacturer: Castair (Cast Air) — Minnesota, USA
- Capacity: 150 CFM
- Maximum Working Pressure: 250 PSIG
- Maximum Inlet Air Temperature: 350°F
- Approach Temperature: Within 15°F of ambient air temperature
- Water Removal: Approximately 65% of total moisture load (based on 250°F inlet air)
- Port Size: 1-1/2 inch NPT (inlet and outlet)
- Power Supply: 115V, 1-phase, 60 Hz
- Mounting Options: Floor standing or suspended overhead
- Air Flow Orientation: Horizontal or vertical
- Dimensions: 43.5 inches H x 14.75 inches W x 46.5 inches D
- Weight: 145 lbs
- Performance Basis: Specifications based on 250°F inlet air temperature at rated CFM
Optional Accessories
- Filter with Automatic Drain: Installs at the aftercooler outlet to capture condensate and purge it automatically — eliminates the need for manual drain intervals on a high-duty aftercooler
- Temperature Control Valve #86816: Regulates cooling fan operation to hold a consistent outlet air temperature — important in cold climates where unregulated cooling can push outlet temperature too low in winter and cause moisture to refreeze in downstream fittings
Why Buy From Air Compressor Factory Direct?
Air Compressor Factory Direct has been specializing in commercial and industrial compressed air equipment since 2016. We carry the full Castair aftercooler lineup — from the FSAC35 for small shops to the AC300 for large industrial installations. When you call us, you are talking to someone who can look at your compressor model and actual CFM rating, confirm the right aftercooler size, and walk through installation considerations including drain placement, piping, and accessory selection.
- Free Shipping: The AC150 ships free to the continental US
- Free Pre-Sale Technical Support: Call before ordering — we will verify that the AC150 matches your compressor output and installation requirements
- Full Manufacturer Warranty: All Castair equipment is covered by full factory warranty
- Honest Sizing Guidance: If your compressor puts out 180 CFM, we will tell you the AC150 is too small and point you to the AC240 — we would rather give you the right answer than a quick sale
- Castair Specialist: We know this product line and stock it
Call 866-217-0063 for quick answers and help!
