Castair T10112HC2-S — 10 HP Single-Phase Tandem Air Compressor, 120-Gallon, 420 RPM
The Castair T10112HC2-S is a 10 horsepower, single-phase, two-stage tandem air compressor with a 120-gallon horizontal ASME tank and slow 420 RPM pump speed. The C2 designation identifies the slower pump configuration — at 420 RPM, this is one of the quietest 10 HP compressors available. Cast iron pumps at 420 RPM run cooler, quieter, and with significantly less wear per cycle than the same capacity unit running at faster RPM. If your shop is in an enclosed building, near customer areas, or anywhere that compressor noise is a genuine problem, the C2 configuration is worth the premium over the C1.
Like all Cast Air tandem units, the T10112HC2-S runs two separate cast iron pumps off a single motor on a shared 120-gallon tank. Single-phase power means no three-phase electrical upgrade is required — this unit runs on standard single-phase service at the voltage appropriate for your area (230V single-phase).
Technical Specifications
- Model: T10112HC2-S
- Horsepower: 10 HP
- Phase: Single-phase (1-phase)
- Configuration: Tandem — 2 pumps, 1 motor
- Stage: Two-stage compression
- Pump RPM: 420 RPM (slowest in the 10 HP tandem lineup)
- Tank: 120-gallon horizontal, ASME-certified
- Dimensions (LxWxH): 85 x 28 x 57 inches
- Weight: 1,305 lbs
- Motor Speed: 1,725 RPM industrial with 15% service factor
- Price: $7,478.05
Cast Iron Pump Construction — Why It Matters
Castair has been building compressors since 1991 with one core principle: cast iron pumps, not aluminum. Cast Air pumps are oil-lubricated, not oil-less, and run at very slow RPMs. This combination means quieter operation, better heat dissipation, and a service life measured in decades rather than years. Here is what is inside every Castair tandem pump:
- All cast iron construction: Cylinders, heads, crankcase, and valve plates — cast iron throughout for superior heat dissipation and durability
- Slow RPM operation: Operating at 420 or 767 RPM depending on configuration — far slower than competitive units. Less heat, less noise, less wear per cycle
- Tapered roller bearings: At both ends of each crankshaft for superior load support and reduced friction under the continuous operation these machines see
- Precision steel connecting rods: Automotive-type rod insert bearings at the crankshaft and needle bearings at the wrist pin — designed for long service intervals
- Disc and spring valves: Stainless steel disc and spring valves provide approximately 10x the service life of standard reed valves — easier to service and more efficient under load
- 4-ring pistons: Better sealing, higher compression efficiency, and less oil carry-over into the air supply
- Centrifugal unloader: Load-free startup every time — the compressor never has to start against tank pressure
Tank, Motor, and Controls
- Powder-coated ASME-certified tank: Horizontal configuration with channel base mounting
- ASME safety valves: Code-compliant pressure relief
- Totally enclosed metal belt guard
- Copper discharge and unloader tubes
- Heavy-duty 1,725 RPM industrial motor with full 15% service factor
- Magnetic starter included (S designation): Motor control fully wired and mounted from the factory
What's Included
- Complete tandem compressor unit (pumps, tank, motor, controls)
- Magnetic motor starter — mounted and wired
- Cast Air "Right from the Start" Kit — everything needed for initial setup and first-day operation
- ASME safety valve(s)
- Copper discharge and unloader tubing
Why a Tandem vs. a Single-Pump Compressor
A tandem compressor runs two separate pump assemblies from a single motor on a shared tank. This design offers real operational advantages that a comparably rated single-pump unit cannot match:
- Higher combined CFM output: Two pumps filling the same tank simultaneously means faster recovery and more sustained air delivery under continuous demand
- Built-in redundancy: If one pump needs service, the other continues operating — a single-pump compressor is either running or completely down
- Lower heat per pump: Neither pump runs at maximum stress continuously — the shared workload runs cooler and extends pump life
- Extended pump service intervals: Runtime hours are split across two pumps — maintenance intervals per pump are effectively doubled
Shipping and Lead Time
These units ship within two weeks of order placement. Note that shipping means leaving the warehouse within two weeks — freight delivery times vary by location and are in addition to the lead time. All orders receive a courtesy call to confirm application requirements and verify the correct unit has been selected for your shop.
C1 vs. C2 Pump Speed — 767 RPM vs. 420 RPM
The C1 configuration (T10112HC1-S) runs at 767 RPM. The C2 configuration (this unit) runs at 420 RPM. Here is what that difference means in practice:
- Noise: Lower RPM means measurably less noise — if your shop is in a building where compressor sound is an issue, the C2 is the correct choice
- Heat: Slower pump speed generates less heat per compression cycle — the pumps run cooler, which extends seal, valve, and ring life
- Air volume per stroke: At 420 RPM, each stroke is slower but the compression ratio per stroke is optimized differently — the pumps are physically larger to compensate for the slower speed while maintaining the rated CFM output
- Weight: The C2 unit weighs 1,305 lbs vs. 1,115 lbs for the C1 — the larger pump assemblies add mass
- Price: The C2 commands a $918 premium over the C1 for the same tank and HP rating
10 HP Tandem Lineup — Configuration Reference
- T10112HC1-S — 10 HP, 1-phase, 120 gal, 767 RPM ($6,560.05)
- T10112HC2-S (this unit) — 10 HP, 1-phase, 120 gal, 420 RPM ($7,478.05)
- T10124HC1-S — 10 HP, 1-phase, 240 gal, 767 RPM ($8,023.75)
- T10124HC2-S — 10 HP, 1-phase, 240 gal, 420 RPM ($9,012.30)
- T10312HC1-S — 10 HP, 3-phase, 120 gal, 767 RPM ($5,660.75)
- T10312HC2-S — 10 HP, 3-phase, 120 gal, 420 RPM ($6,579.60)
- T10324HC1-S — 10 HP, 3-phase, 240 gal, 767 RPM ($7,194.15)
When Does a Shop Need the T10112HC2-S
This unit is the right choice when:
- You have single-phase power and need 10 HP capacity with the quietest possible pump operation
- Your shop is in an enclosed space, adjacent to offices, or in any location where compressor noise is a documented issue
- You prioritize long pump life over the lower purchase price of the C1 configuration
- You are running equipment that benefits from the lower vibration signature of a slower pump
Choose the T10112HC1-S instead when: The noise difference is not a concern and the $918 price difference is significant for your budget.
Step up to the T10124HC2-S when: You need the slow-pump configuration with a 240-gallon tank for higher air storage capacity.
Why Buy From Air Compressor Factory Direct?
- Authorized Cast Air dealer since 2016 — we know the lineup and can help you choose the right tank size, phase, and pump speed for your specific shop
- Free shipping on this order — freight included to your location
- Free technical support at 866-217-0063 — call before ordering to confirm phase requirements, tank sizing, and CFM needs for your application
- Full Cast Air manufacturer warranty on every component
- Honest buying guidance: If a different HP or configuration is a better fit, we will tell you before you order a $6,000+ compressor
Call 866-217-0063 for quick answers and help!
