The Castair D5324HC1-S is a 10 HP total (2x5 HP) two-stage duplex air compressor running on 3-phase power with a 240-gallon ASME horizontal tank. This is the 3-phase equivalent of the D5124HC1-S — same pumps, same CFM, same tank, different electrical: 3-phase motors run more efficiently, draw less current per phase at equivalent output, and are the right choice for any shop that has 3-phase service available.
Output is 35 CFM at 175 PSI (44 CFM at 0 PSI). The C1 pump configuration runs at 767 RPM. C1 at 767 RPM is the moderate-speed configuration — lighter and lower cost than C2. Both configurations deliver the same CFM output; the difference is operating speed, noise level, and service longevity.
Duplex configuration means two independent pump-motor assemblies on one tank. If one pump needs service, the other carries the shop. Magnetic starter is factory mounted and wired — this ships ready to connect to your electrical service.
Key Features
Pump Construction — C1 Configuration
- All Cast Iron Construction: Cast iron cylinders, heads, and crankcase throughout
- C1 Pump at 767 RPM: Moderate-speed C1 pump — solid performance for typical shop duty
- Tapered Roller Bearings: Both crankshaft ends — better load support than ball bearings
- Precision Steel Connecting Rods: Automotive-type insert bearings at crankshaft and wrist pin
- Disc and Spring Valves: Higher efficiency, easier service than reed valves
- 4-Ring Pistons: Better sealing and reduced oil carry-over
- Centrifugal Unloader: Loadless start every time
Two-Stage Compression
- Two-Stage Design: To 175 PSI in two stages — more efficient and cooler than single-stage at this pressure
- 44 CFM @ 0 PSI / 35 CFM @ 175 PSI: Consistent output
Tank, Controls, and Electrical
- 240-gallon ASME Horizontal Tank: Powder-coated steel with channel base; ASME certified
- Dimensions (L x W x H): 85" x 30" x 64"
- 3-Phase Electrical: More efficient motor operation than single-phase at equivalent HP; lower per-phase current draw; standard for industrial shop installations
- Magnetic Starter — Mounted and Wired: Factory-installed; handles 3-phase motor switching with overload protection
- ASME Safety Valves: Factory installed
- Metal Belt Guard — Totally Enclosed: OSHA-compliant
- Heavy Duty 1725 RPM Industrial Motors: Full 15% service factor
Duplex Redundancy
- Two Independent Pump-Motor Assemblies: Service one while the other runs
- No Production Downtime for Routine Maintenance
What's in the Box
- Castair D5324HC1-S duplex compressor (two 5 HP pump-motor assemblies, 240-gallon ASME tank, skid)
- Magnetic starter — factory mounted and wired
- ASME safety valves (factory installed)
- Pressure gauges and controls
- Belt guards (factory installed)
- Owner's manual
Ships on freight. Weight 1,430 lbs shipped — confirm delivery access and unloading equipment.
Available Factory-Mounted Options
- Low Oil Control (#6304x2M)
- Hour Meters (#HRM75x2M for 230V / #HRM460x2M for 460V)
- Alternator (#ALT230M / #ALT460M): Rotates lead pump each cycle for even wear
- Electronic Auto Drain (#SDV03M)
- Aftercooler (#BGAC1x2M — 70 CFM rated)
- Belt Tensioner (#184Dx2M — 5 HP)
- Vibration Pads (#VP1004 — set of 4)
- Right From The Start Kit (#RFS001D — 10 HP)
- All Options C1 Package (#AOC1D)
Available Configurations — 10 HP 3-Phase Duplex
- D5312HC1-S — 10 HP, 3-Phase, 120 gal, 767 RPM C1 pump: Fastest pump, lower cost, 1,080 lbs shipped
- D5312HC2-S — 10 HP, 3-Phase, 120 gal, 420 RPM C2 pump: Slower, quieter, longer life, 1,270 lbs shipped
- D5324HC1-S — 10 HP, 3-Phase, 240 gal, 767 RPM C1 pump: More tank storage, 1,430 lbs shipped
- D5324HC2-S — 10 HP, 3-Phase, 240 gal, 420 RPM C2 pump: Maximum storage and longevity, 1,620 lbs shipped
When Does a Shop Need This vs. Stepping Up or Down?
The D5324HC1-S fits when:
- You have 3-phase power and want the most efficient 10 HP duplex option
- Your sustained CFM demand is in the 25–35 CFM range
- Redundancy matters — you cannot shut down air to service the compressor
Step up when: CFM demand consistently exceeds 35 CFM — move to the 15 HP duplex (D7312/D7324 series at 49.6 CFM) or 20 HP (D10312/D10324 at 70 CFM).
Consider single-phase versions (D5112/D5124) only if: 3-phase is not available at your location.
Technical Specifications
- Model Number: D5324HC1-S
- Series: Duplex Series
- Horsepower (each / total): 2x5 HP / 10 HP total
- Electrical: 3-Phase
- Pump Configuration: C1
- Pump RPM: 767
- CFM @ 0 PSI: 44
- CFM @ 175 PSI: 35
- Maximum Pressure: 175 PSI
- Tank Capacity: 240 gallons
- Tank Style: ASME horizontal with channel base
- Dimensions (L x W x H): 85" x 30" x 64"
- Shipped Weight: 1,430 lbs
- Magnetic Starter: Included, factory mounted and wired
Why Buy From Air Compressor Factory Direct?
We have specialized in professional-grade shop compressors since 2016. Choosing between C1 and C2 pumps, 120 and 240 gallon tanks, or single-phase and 3-phase configurations is not guesswork — it depends on your actual CFM demand, electrical service, duty cycle, and budget. Call us and we will work through it with you before you order a freight shipment.
- Free Shipping on qualifying orders (freight; site access confirmation required)
- Free Technical Support — 866-217-0063
- Full Manufacturer Warranty — Castair backs their duplex systems
- Honest Configuration Guidance
Call 866-217-0063 for quick answers and help!
