The Castair D10124HC2-S is a 20 total horsepower duplex two-stage air compressor on a 240-gallon horizontal ASME tank, running on single-phase electricity. It is the same 2x10HP HC2 pump package as the D10112HC2-S, but with double the tank capacity — 240 gallons instead of 120. The result is a unit that handles high peak demand applications where a smaller tank would cycle the pumps constantly or allow pressure to sag between cycles. At 1,820 lbs and with a magnetic starter mounted and wired from the factory, this is a production-grade machine for shops that run continuous or near-continuous air demand on a single-phase service.
Why 240 Gallons Matters
Tank size determines how long the compressor can supply demand before the pumps kick in, and how severe the pressure swings are during high-draw periods. With a 240-gallon receiver, a shop pulling 50-60 CFM for spray painting or sandblasting will see much steadier output pressure and less pump cycling compared to a 120-gallon system. Fewer cycles means less motor start stress, longer pump life, and a more consistent air supply to the tool.
The tradeoff is size and weight: the D10124HC2-S is 85" x 30" x 64" and weighs 1,820 lbs — 350 lbs heavier than the D10112HC2-S and 4" wider and 7" taller. You need a floor that can support it and a doorway large enough to move it in.
Pump and Motor Specifications
- Configuration: Duplex (two pumps, two motors)
- Total HP: 20 HP (2 x 10 HP)
- Phase: Single-phase
- Pump RPM: 758 (HC2 pump)
- CFM at 0 PSI: 90 CFM combined
- CFM at 175 PSI: 70 CFM combined
- Max Pressure: 175 PSI
- Stage: Two-stage
Tank and Physical Specs
- Tank Capacity: 240 gallons, horizontal ASME
- Dimensions (LxWxH): 85" x 30" x 64"
- Weight: 1,820 lbs
- Tank Finish: Powder coated
- Safety Valve: ASME rated, installed
- Magnetic Starter: Mounted and wired (factory installed)
Cast Iron Pump Features
- All cast iron construction for long service life and quiet operation
- Slow RPM design (758 RPM HC2) reduces heat and extends valve life
- Tapered roller bearings at both crankshaft ends
- Precision steel connecting rods with automotive-type rod insert bearings
- Disc and spring valves for easy service and reliability
- 4-ring pistons for efficiency and reduced oil carry-over
- Centrifugal unloader for loadless starts
Configuration Comparison — 2x10HP Single-Phase
- D10112HC2-S — 120gal, HC2 758 RPM, 85x28x57, 1,470 lbs — lighter, smaller footprint
- D10124HC2-S — 240gal, HC2 758 RPM, 85x30x64, 1,820 lbs — double storage (this unit)
- D10112HC3-S — 120gal, HC3 570 RPM, 94x28x57, 1,800 lbs — slower/quieter pump
- D10124HC3-S — 240gal, HC3 570 RPM, 94x30x64, 2,150 lbs — max storage + slowest RPM
When Does a Shop Need This
The D10124HC2-S is the right choice when: Your shop runs spray painting, sandblasting, plasma cutting, or other high-draw continuous processes that would exhaust a 120-gallon tank too quickly; you are on single-phase power; and you need the duplex reliability of two independent pump/motor sets.
Step down to D10112HC2-S if your air usage is more intermittent — tool impact wrenches, tire inflation, spot blowguns — and 120 gallons provides adequate buffer between pump cycles.
Step up to D10124HC3-S if you also want the slower-running, quieter HC3 pump in the 240-gallon package.
Consider three-phase (D10324HC2-S) if three-phase service is available — more efficient motor operation at this horsepower level.
Technical Specifications Summary
- Model: D10124HC2-S
- Manufacturer: Castair (Cast Air, Inc.) — Spicer, Minnesota
- Total HP: 20 HP (2 x 10 HP)
- Phase: Single-phase
- Pump RPM: 758 (HC2)
- CFM @ 0 PSI: 90
- CFM @ 175 PSI: 70
- Tank: 240 gallon, horizontal, ASME, powder coated
- Dimensions (LxWxH): 85" x 30" x 64"
- Weight: 1,820 lbs
- Magnetic Starter: Included, factory mounted and wired
- Safety Valve: ASME rated, installed
Why Buy From Air Compressor Factory Direct?
We have been selling industrial compressors since 2016. At this price point, the tank size and pump configuration decision matters — we can help you choose between 120 and 240 gallons based on your actual CFM demand and duty cycle. Free shipping, free technical support at 866-217-0063, full Castair manufacturer warranty.
Call 866-217-0063 for quick answers and help!
