Castair I10112HC3-S

Castair I10112HC3-S — 10 HP Single-Phase Industrial Air Compressor, 120-Gallon Horizontal Tank, Slow-Speed C3 Pump with Mounted Starter

The Castair I10112HC3-S is the premium 10 HP single-phase option in the Cast Air Industrial lineup. Where the C2 version of this compressor runs its pump at 758 RPM, this C3 model runs at 570 RPM — 25% slower. Same 10 HP motor, same 120-gallon horizontal tank, same 45.0 CFM at 0 PSI and 35.0 CFM at 175 PSI output. The slower pump speed means less heat generated per cycle, less mechanical wear per hour of operation, and a noticeably quieter machine. The trade-off is weight — 1,040 lbs versus 875 lbs for the C2 — and price. If your shop is buying one compressor to last 20 or 25 years, the C3 is the right pump.

Like all '-S' models, the magnetic motor starter is factory-mounted and wired. Your electrician connects the incoming power — the overload protection and proper motor control are already done.

Cast Iron Pump Engineering — Why This Matters for Shop Longevity

Every Castair Industrial Series compressor is built around their oversized cast iron pump. Here is what separates these from lighter-duty machines:

• All cast iron construction — cylinder heads, crankcase, and cylinders are cast iron throughout. Cast iron manages heat better than aluminum and wears far more slowly under continuous load.
• Tapered roller bearings at both ends of the crankshaft — not ball bearings. Tapered rollers handle both radial and thrust loads simultaneously, which is exactly what a reciprocating pump crankshaft sees in operation.
• Precision steel connecting rods with automotive-type insert bearings — at both the crankshaft journal and the wrist pin. These are the same bearing design used in automotive engines. They are replaceable when worn — not a throwaway assembly.
• Disc and spring valves — simpler to service than reed valves, more efficient at high discharge pressures, and more reliable over years of cycling.
• 4-ring pistons — two extra rings versus typical 2-ring piston designs. Better compression sealing, significantly less oil carry-over into the air stream.
• Centrifugal unloader — the pump starts unloaded on every cycle without exception. This reduces motor starting current, reduces wear on the motor and belts, and eliminates the hard-start problem common in compressors that attempt to restart against pressure.

What the C3 Pump Adds

• 570 RPM pump speed — versus 758 RPM on the C2. This is a significant difference in operating temperature and wear rate over 10,000+ hours of shop use.
• Heavier cast iron construction — the C3 pump is physically larger and heavier than the C2. This is not just marketing weight — it is more iron absorbing more heat, more crankshaft mass maintaining smoother rotation, and more bearing surface area handling the load.
• Same output — 45.0 CFM at 0 PSI, 35.0 CFM at 175 PSI. The slower speed does not reduce output; it just gets there with less stress on the components.

Tank, Motor, and Controls

• ASME-coded steel tank — powder-coated for corrosion resistance. ASME certification means the tank was designed and tested to a recognized pressure vessel standard, not just stamped with a number.
• ASME safety valve — factory-installed.
• Metal belt guard, totally enclosed — not a plastic cover.
• Copper discharge and unloader tubing or stainless-steel braided flex line — not plastic hose or rubber.
• Heavy-duty 1,725 RPM industrial motor with a minimum 15% service factor. This means the motor can sustain loads above its nameplate rating without tripping. In a shop where the compressor runs all day, the service factor is not a marketing number — it is the difference between a motor that lasts a decade and one that burns up in two years.

Who Should Buy the C3 Over the C2

• Shops planning to keep this compressor for 15 or more years
• Operations running continuous duty — the compressor is on and cycling most of the business day
• Shops where noise level matters — machine shops, customer-facing areas, attached offices
• Buyers who want the lowest long-term cost of ownership and are willing to pay more upfront for slower wear rates

When to Step Down to the C2

• Budget is a primary constraint and 10-15 year service life is acceptable
• Light to moderate duty use — the compressor is not running continuously
• Weight is a concern — 1,040 lbs requires a solid floor and proper equipment to move

What's in the Box

• Castair I10112HC3-S compressor assembly (pump, motor, tank, all factory-assembled and tested)
• Factory-mounted and wired magnetic motor starter
• ASME safety valve (installed)
• Pressure switch (installed)
• Metal belt guard (installed)
• Copper discharge and unloader tubing or stainless-steel braided flex line (installed)
• Operator documentation

Factory-installed options available on this unit include: low oil shutdown control (#6304M), hour meter (#HRM75M for 230V or #HRM460M for 460V), air-operated auto drain (#ADVSM), electronic auto drain (#SDV03M), dual controls (#DC2 for C2 pumps), intake noise silencer (#SA100x2M for C2/C3), belt tensioner (#215DM for 10 HP), time delay (#TD100M for 230V), vibration isolation pads (#VP1004), beltguard aftercooler (#BGAC1M — 35 CFM, appropriate for 10 HP), and Right from the Start Kit (#RFS001 for C1/C2). Ordering all asterisk-marked options qualifies for 10% discount on options. Ask us about pre-configured option packages.

Technical Specifications

• Model: I10112HC3-S
• Horsepower: 10 HP
• Phase: 1-phase (single-phase)
• Tank capacity: 120 gallons
• Tank orientation: Horizontal (channel base)
• Pump type: C3 (two-stage cast iron, slow-speed)
• Pump RPM: 570
• CFM at 0 PSI: 45.0
• CFM at 175 PSI: 35.0
• Max working pressure: 175 PSI
• Motor speed: 1,725 RPM
• Motor service factor: 15% minimum
• Dimensions (L x W x H): 69 x 24 x 50 inches
• Weight: 1,040 lbs
• Tank certification: ASME
• Starter: Factory-mounted magnetic motor starter (included)
• Manufacturer: Castair (Cast Air Inc., Spicer, MN)

Available Configurations — Cast Air Industrial 10 HP Single-Phase Lineup

Three-phase versions (I10312-series) are available with identical output specs. If your facility has three-phase power, use it — three-phase motors run cooler, start easier, and last longer under continuous load.

Why Buy From Air Compressor Factory Direct?

We have been selling industrial air compressors since 2016 and carry the full Cast Air Industrial Series lineup. When you call us, you reach someone who can tell you whether the C2 or C3 pump is right for your application, what electrical service you need, which options are worth adding, and whether horizontal or vertical tank orientation fits your floor plan. We offer free shipping on qualifying orders, full manufacturer warranty support, and straight talk about which unit fits your shop — not a push toward the most expensive option.

Call 866-217-0063 for quick answers and help!