{"product_id":"castair-15hp-2x7-5-duplex-duplex-air-compressor-120gal-d7312hc1","title":"Castair 15HP (2x7.5) Duplex Duplex Air Compressor 120Gal - D7312HC1","description":"\u003cp\u003eThe Castair D7312HC1-S is a 15HP (2×7.5HP) three-phase duplex air compressor on a 120-gallon horizontal ASME tank with twin C1 cast iron pumps running at 895 RPM. If your shop has three-phase electrical service, this is where the Castair duplex lineup makes the most economic sense. Three-phase motors run at lower amperage for the same horsepower output, generate less heat, and last longer under sustained duty than single-phase equivalents. You get the same 49.6 CFM at 175 PSI as the single-phase version at 1,210 lbs. — the lightest 7.5HP duplex in the Castair catalog.\u003c\/p\u003e\n\n\u003cp\u003eThe duplex architecture means two complete, independent compressor units sharing one tank. When one pump is serviced, the other keeps running. For shops where the compressor is mission-critical — production facilities, fleet maintenance operations, full-time body shops — this redundancy is not optional. It is how you stay in business when hardware fails.\u003c\/p\u003e\n\n\u003ch2\u003eWho Needs the D7312HC1-S\u003c\/h2\u003e\n\u003cp\u003eAny three-phase facility that needs duplex reliability in the 7.5HP class. Auto repair shops, tire centers, collision repair facilities, manufacturing operations. At 49.6 CFM at 175 PSI, this unit handles three to four air tool operators simultaneously without significant pressure drop. Three-phase power means lower monthly electrical costs compared to running the same HP on single-phase because three-phase motors draw current more efficiently and generate less heat doing it.\u003c\/p\u003e\n\n\u003cp\u003eIf your building already has three-phase service, there is no reason to run single-phase compressor motors. The D7312HC1-S takes advantage of that electrical infrastructure to deliver the same output at lower operating cost and lower motor stress.\u003c\/p\u003e\n\n\u003ch2\u003eCastair C1 Pump Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAll cast iron construction:\u003c\/strong\u003e Cylinders, crankcase, and valve plates are cast iron throughout — not aluminum. Cast iron is quieter under load, more dimensionally stable across temperature cycles, and more durable in continuous duty applications.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e895 RPM operating speed:\u003c\/strong\u003e The C1 pump runs at 895 RPM, roughly half the speed of many imported pump assemblies. Lower RPM generates less heat per hour of operation and extends the service life of bearings, rings, and valves proportionally.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTapered roller bearings:\u003c\/strong\u003e Both crankshaft ends run on tapered roller bearings for superior support under the combined radial and axial loads of reciprocating operation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrecision steel connecting rods:\u003c\/strong\u003e Automotive-type rod insert bearings at the crankshaft journal and bearings at the wrist pin for long service life under sustained duty cycles.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDisc and spring valves:\u003c\/strong\u003e More efficient and more durable than reed valves under continuous operation. When valves wear, you replace the valve components — not the pump head.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e4-ring pistons:\u003c\/strong\u003e Four compression rings per piston for better sealing and lower oil carry-over into the air supply. This matters if you are running spray equipment or precision air tools where oil contamination causes problems.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCentrifugal unloader:\u003c\/strong\u003e Every startup is unloaded — the pump reaches operating speed before compression load engages, protecting both motor windings and pump internals at each cycle.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTank, Motor, and Control Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e120-gallon horizontal ASME tank:\u003c\/strong\u003e Powder-coated steel with channel base. ASME certified pressure vessel construction.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eASME safety valves:\u003c\/strong\u003e Certified pressure relief hardware — factory-original, not aftermarket replacements.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFully enclosed metal belt guard:\u003c\/strong\u003e Meets OSHA requirements and protects the drive system from shop debris.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCopper discharge and unloader tube or stainless-steel braided flex line:\u003c\/strong\u003e No plastic fittings in the discharge path where heat and pressure combine.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeavy-duty 1725 RPM three-phase industrial motors:\u003c\/strong\u003e Full 15% service factor or higher. Three-phase motors run at lower amperage for the same horsepower output and generate less heat than single-phase equivalents — an inherent advantage of three-phase electrical service.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnetic starter mounted and wired (-S models):\u003c\/strong\u003e Factory-installed and pre-wired magnetic motor starters. You connect your three-phase electrical service to the panel — the internal wiring is complete.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eThree-Phase vs. Single-Phase: The Real Difference\u003c\/h2\u003e\n\u003cp\u003eFor the same 7.5HP per motor, three-phase motors draw lower amperage, run cooler, start more smoothly, and last longer than single-phase motors. A three-phase motor does not rely on start capacitors or centrifugal switches for startup — it starts cleanly every time. For a duplex compressor that starts multiple times per day over years of operation, those motor advantages compound into meaningfully longer motor life and lower electrical operating costs.\u003c\/p\u003e\n\u003cp\u003eIf your facility has three-phase service, use it. The D7312HC1-S weighs 30 lbs. less than its single-phase C1 equivalent (1,210 lbs. vs. 1,240 lbs.) and costs less to run per operating hour.\u003c\/p\u003e\n\n\u003ch2\u003eFactory-Mounted Options Available\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow Oil Control (#6304x2M):\u003c\/strong\u003e Automatic shutdown before oil starvation damages pump internals. Essential for high-duty applications.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHour Meter (#HRM75x2M for 230V, #HRM460x2M for 460V):\u003c\/strong\u003e Track actual operating hours per pump for maintenance scheduling. Critical for high-use shops.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAlternator (#ALT230M or #ALT460M):\u003c\/strong\u003e Automatic load alternation between the two pump units on each cycle to equalize long-term wear.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eElectronic Auto Drain (#SDV03M):\u003c\/strong\u003e Timer-controlled condensate drain. Eliminates the maintenance failure of not draining the tank regularly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDual Control (#DC1x2M for C1 pumps):\u003c\/strong\u003e Enables continuous unloaded operation during high-demand periods. Reduces motor starts per hour, which directly reduces both electrical cost and motor wear. Note: Dual control is standard on C3 units but optional on C1 and C2.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIntake Noise Silencers (#SA100x2M for C1 duplex):\u003c\/strong\u003e Inlet silencers on each pump head reduce intake noise without restricting airflow.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBelt Tensioner (#215Dx2M for 7.5-10HP):\u003c\/strong\u003e Spring-loaded belt tensioning for consistent drive geometry as belts stretch over time.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRight From the Start Kit (#RFS001D for 10HP):\u003c\/strong\u003e Consolidated maintenance kit for first service interval.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVibration Pads (#VP1004):\u003c\/strong\u003e Isolation pads to reduce floor vibration transmission from the unit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBelt Guard Aftercooler (#BGAC1x2M, 70 CFM for 10-20HP units):\u003c\/strong\u003e Reduces moisture in the air system by cooling compressed air before it enters the tank.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAll Options Bundle (#AOC1D for C1):\u003c\/strong\u003e Order all asterisk options together for 10% off the options total.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAvailable Configurations — 7.5HP Three-Phase Duplex\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eD7312HC1-S (this unit):\u003c\/strong\u003e 2×7.5HP, three-phase, C1 pump (895 RPM), 120-gal, 49.6 CFM@175 PSI, 1,210 lbs. — starter included.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eD7312HC2-S:\u003c\/strong\u003e 2×7.5HP, three-phase, C2 pump (585 RPM), 120-gal, 56.2 CFM@175 PSI, 1,400 lbs. — more CFM, heavier pump, same tank.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eD7324HC1-S:\u003c\/strong\u003e 2×7.5HP, three-phase, C1 pump (895 RPM), 240-gal, 49.6 CFM@175 PSI, 1,560 lbs. — same pump output with larger air storage.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eD7324HC2-S:\u003c\/strong\u003e 2×7.5HP, three-phase, C2 pump (585 RPM), 240-gal, 56.2 CFM@175 PSI, 1,750 lbs. — maximum CFM output on maximum tank in three-phase.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhen Does a Shop Need This vs. Stepping Up or Down\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eStep down (single-pump three-phase industrial):\u003c\/strong\u003e If your shop does not need backup redundancy and 35-49 CFM from a single pump covers your demand, the Castair Industrial Series I7312HC2-S (single-pump, three-phase, 120-gal) is a simpler, lower-cost option.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThis unit (D7312HC1-S):\u003c\/strong\u003e Three-phase facility, three to four simultaneous air tool operators, need for backup redundancy. The most economical three-phase duplex entry point in the 7.5HP class. Lighter than the C2 version, slightly lower CFM.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStep up (C2 pump or larger tank):\u003c\/strong\u003e If you need 56 CFM instead of 49.6, the D7312HC2-S uses the same 120-gallon frame with the C2 pump upgrade. If your demand cycle is sustained enough to justify a larger tank, the D7324HC1-S delivers the same C1 pump output on a 240-gallon tank.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eModel:\u003c\/strong\u003e D7312HC1-S\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConfiguration:\u003c\/strong\u003e Duplex (2 pumps, 2 motors)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMotor:\u003c\/strong\u003e 2×7.5HP, 15HP total\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePhase:\u003c\/strong\u003e Three-phase\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePump Series:\u003c\/strong\u003e C1 (cast iron)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePump RPM:\u003c\/strong\u003e 895\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCFM @ 0 PSI:\u003c\/strong\u003e 64.8\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCFM @ 175 PSI:\u003c\/strong\u003e 49.6\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTank:\u003c\/strong\u003e 120-gallon horizontal ASME\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions (L×W×H):\u003c\/strong\u003e 85 × 28 × 57 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 1,210 lbs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMagnetic Starter:\u003c\/strong\u003e Included, factory-mounted and wired\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMax Pressure:\u003c\/strong\u003e 175 PSI\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h3\u003e\n\u003cp\u003eWe have been selling and supporting professional-grade air compressors since 2016. We stock the full Castair duplex catalog — both pump series, all tank sizes, single-phase and three-phase, with and without starters. Free shipping on all orders. Free tech support at 866-217-0063 — call before you order if you want help comparing the C1 and C2 pump options, calculating your actual CFM requirement, or determining whether 120 or 240 gallons of tank storage fits your shop's demand profile. Full manufacturer warranty. Honest guidance — if a different configuration fits better, we will say so.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCall 866-217-0063 for quick answers and help!\u003c\/strong\u003e\u003c\/p\u003e","brand":"Cast Air","offers":[{"title":"Default Title","offer_id":53342542659797,"sku":"D7312HC1","price":14218.46,"currency_code":"USD","in_stock":true}],"url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-15hp-2x7-5-duplex-duplex-air-compressor-120gal-d7312hc1","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}