{"product_id":"castair-d15312hc3-s","title":"Castair D15312HC3-S","description":"\u003cp\u003eThe Castair D15312HC3-S is the largest duplex compressor in the Castair lineup — a 30 HP total (2x15 HP) two-stage system running on 3-phase power with a 120-gallon ASME horizontal tank. This is a production-grade machine designed for shops where compressed air is a critical utility: high-volume automotive shops, fleet maintenance operations, body shops running multiple spray guns and air tools simultaneously, and industrial facilities that need sustained high-CFM output with built-in redundancy.\u003c\/p\u003e\n\n\u003cp\u003eAt 100.4 CFM at 175 PSI (123.4 CFM at 0 PSI), this system delivers more air than most single-unit compressors in its class. The duplex configuration means two independent pump-motor assemblies share one tank — if one unit needs service, the other keeps your shop running. That backup redundancy is the core reason to choose a duplex over a single-unit machine at this power level.\u003c\/p\u003e\n\n\u003cp\u003eCastair builds these in Spicer, Minnesota, family owned since 1991. The duplex line uses the same industrial pump design as their single-unit Industrial Series — cast iron construction, slow RPM operation (795 RPM on the C3 pump), tapered roller bearings, and automotive-type rod insert bearings. These are not budget machines rebranded with a duplex skid; they are purpose-built for continuous shop use.\u003c\/p\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\n\u003ch3\u003ePump Construction — C3 Configuration\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAll Cast Iron Construction:\u003c\/strong\u003e Cast iron cylinders, heads, and crankcase — quiet operation and long service life\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eC3 Pump at 795 RPM:\u003c\/strong\u003e The C3 designation means the slowest-running, heaviest-duty pump Castair offers at this power level — lower RPM means less heat, less wear, quieter operation\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTapered Roller Bearings:\u003c\/strong\u003e Both ends of the crankshaft, providing superior load support and less friction compared to ball bearings\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePrecision Steel Connecting Rods:\u003c\/strong\u003e Automotive-type rod insert bearings at both the crankshaft and wrist pin — serviceable and built to last\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDisc and Spring Valves:\u003c\/strong\u003e Higher efficiency and easier service than reed valves — straightforward to replace when maintenance is due\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e4-Ring Pistons:\u003c\/strong\u003e Better sealing efficiency and reduced oil carry-over into the discharge air compared to 2-ring designs\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCentrifugal Unloader:\u003c\/strong\u003e Loadless start-up every time — the pump starts spinning before compression begins, eliminating the heavy start current spike of loaded starts\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTwo-Stage Compression System\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTwo-Stage Design:\u003c\/strong\u003e First stage compresses to an intermediate pressure; second stage brings it to 175 PSI — more efficient and cooler running than single-stage at high pressure\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e175 PSI Maximum Operating Pressure:\u003c\/strong\u003e Higher than single-stage units (typically 125-150 PSI), meeting requirements for two-stage applications\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCopper Discharge and Unloader Tube or Stainless Steel Braided Flex Line:\u003c\/strong\u003e Castair uses either depending on configuration — both handle the heat and pressure at the discharge port\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTank, Controls, and Electrical\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e120-Gallon ASME Horizontal Tank:\u003c\/strong\u003e Powder-coated steel with channel base supports — ASME certified for pressure vessel safety\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eASME Safety Valves:\u003c\/strong\u003e Installed on both pump discharge lines\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMagnetic Starter — Mounted and Wired:\u003c\/strong\u003e Factory-installed mag starter handles the 3-phase motor switching, provides overload protection, and includes low-voltage release\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDuplex Alternator Control (Standard on C3):\u003c\/strong\u003e Automatically alternates which pump starts first on each cycle, equalizing wear and run hours between the two units\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMetal Belt Guard — Totally Enclosed:\u003c\/strong\u003e OSHA-compliant, keeps debris and hands clear of the drive belt and pulleys\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHeavy Duty 1725 RPM Industrial Motors:\u003c\/strong\u003e Full 15% service factor or higher — rated for the sustained duty cycles of shop use\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eDuplex Redundancy — The Core Value Proposition\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTwo Independent Pump-Motor Units:\u003c\/strong\u003e Either unit can carry the shop's air demand while the other is serviced or repaired\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNo Production Downtime for Routine Maintenance:\u003c\/strong\u003e Change oil, replace belts, service valves — all while the shop keeps running on the second unit\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAutomatic Failover:\u003c\/strong\u003e If one unit trips on overload or shuts down on low oil (with optional low oil control), the second unit picks up the load automatically\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhat's in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eCastair D15312HC3-S duplex compressor (two 15 HP pump-motor assemblies, 120-gallon ASME tank, common skid)\u003c\/li\u003e\n  \u003cli\u003eMagnetic starter — factory mounted and wired\u003c\/li\u003e\n  \u003cli\u003eDuplex alternator control (standard on C3 configuration)\u003c\/li\u003e\n  \u003cli\u003eASME safety valves (factory installed)\u003c\/li\u003e\n  \u003cli\u003ePressure gauges and controls\u003c\/li\u003e\n  \u003cli\u003eBelt guards (factory installed)\u003c\/li\u003e\n  \u003cli\u003eOwner's manual and service documentation\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003eOptional factory-mounted accessories available — see Available Options section. Ships on freight; call for delivery and rigging requirements.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch2\u003eAvailable Factory-Mounted Options\u003c\/h2\u003e\n\u003cp\u003eCastair offers the following options that can be factory-mounted and wired before shipment:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLow Oil Control (#6304x2M):\u003c\/strong\u003e Shuts down the affected pump on low oil level — protects the pump from running dry\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHour Meters (#HRM75x2M for 230V \/ #HRM460x2M for 460V):\u003c\/strong\u003e Track runtime on each pump independently for accurate service scheduling\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eElectronic Auto Drain (#SDV03M):\u003c\/strong\u003e Timed automatic tank drain — eliminates manual draining and the moisture buildup that causes tank corrosion\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAftercooler (#BGAC2x2M — 100 CFM rated):\u003c\/strong\u003e Cools compressed air before it reaches your distribution system, dramatically reducing moisture in the lines\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBelt Tensioner (#254Dx2M — for 15 HP):\u003c\/strong\u003e Simplifies belt tension adjustment and maintenance\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eVibration Pads (#VP1004 — set of 4):\u003c\/strong\u003e Reduces transmitted vibration to the floor\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRight From The Start Kit (#RFS003D — for 25 and 30 HP):\u003c\/strong\u003e Startup kit with recommended filters, lubricants, and initial service items\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAll Options C3 Package (#AOC3D):\u003c\/strong\u003e Bundle all available options in one order\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIntake Noise Silencers (#SA100x4M — C2\/C3):\u003c\/strong\u003e Additional intake silencing for noise-sensitive environments\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAvailable Configurations — Duplex Lineup\u003c\/h2\u003e\n\u003cp\u003eHere is how the D15312HC3-S fits into the Castair duplex lineup by total HP and tank size:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eD5112HC1-S — 10 HP (2x5), 1-Phase, 120 gal, 35 CFM @ 175 PSI:\u003c\/strong\u003e Entry-level duplex for shops needing single-phase redundancy\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eD5312HC1-S — 10 HP (2x5), 3-Phase, 120 gal, 35 CFM @ 175 PSI:\u003c\/strong\u003e Same output as above on 3-phase power\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eD7312HC1 — 15 HP (2x7.5), 3-Phase, 120 gal, 49.6 CFM @ 175 PSI:\u003c\/strong\u003e Mid-tier duplex, solid for busy shops\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eD10312HC2-S — 20 HP (2x10), 3-Phase, 120 gal, 70 CFM @ 175 PSI:\u003c\/strong\u003e High-output duplex for demanding shops\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eD15312HC3-S (this unit) — 30 HP (2x15), 3-Phase, 120 gal, 100.4 CFM @ 175 PSI — $13,098.85:\u003c\/strong\u003e Top of the duplex lineup at 120 gallons\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eD15324HC3-S — 30 HP (2x15), 3-Phase, 240 gal, 100.4 CFM @ 175 PSI — $14,509.00:\u003c\/strong\u003e Same output, double the tank storage for shops with high peak demand\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\u003cp\u003e\u003cstrong\u003eThe D15312HC3-S is the right machine when:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eYour shop runs multiple spray guns, large air tools, or high-CFM equipment simultaneously and needs 100+ CFM at sustained pressure\u003c\/li\u003e\n  \u003cli\u003eYou have 3-phase power available — 3-phase motors run more efficiently and with less electrical stress than equivalent single-phase at this power level\u003c\/li\u003e\n  \u003cli\u003eDowntime is not an option — the duplex configuration means maintenance happens without shutting down production\u003c\/li\u003e\n  \u003cli\u003eYou need 175 PSI two-stage pressure for all connected equipment\u003c\/li\u003e\n  \u003cli\u003eThe 120-gallon tank is sufficient for your usage pattern — if you have very high peak demand with short intervals, the 240-gallon D15324HC3-S is worth the additional investment\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eStep down if:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eYour CFM demand is under 70 CFM — the 20 HP (D10312HC2-S) or 15 HP (D7312HC2-S) duplex units cost significantly less and will cover you\u003c\/li\u003e\n  \u003cli\u003eYou do not have 3-phase power — go to the D10124HC2-S or D7124HC2-S single-phase duplex instead\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eStep up if:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eYour peak demand exceeds the 120-gallon tank's ability to recover fast enough — go to the D15324HC3-S with the 240-gallon tank\u003c\/li\u003e\n  \u003cli\u003eYou need more than 100 CFM — at that point you are looking at a custom industrial system or multiple Castair units in parallel\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eModel Number:\u003c\/strong\u003e D15312HC3-S\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSeries:\u003c\/strong\u003e Duplex Series\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHorsepower (each \/ total):\u003c\/strong\u003e 2x15 HP \/ 30 HP total\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eElectrical:\u003c\/strong\u003e 3-Phase\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePump Configuration:\u003c\/strong\u003e C3\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePump RPM:\u003c\/strong\u003e 795\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCFM @ 0 PSI:\u003c\/strong\u003e 123.4\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCFM @ 175 PSI:\u003c\/strong\u003e 100.4\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaximum Pressure:\u003c\/strong\u003e 175 PSI\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTank Capacity:\u003c\/strong\u003e 120 gallons\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTank Style:\u003c\/strong\u003e ASME horizontal with channel base\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDimensions (L x W x H):\u003c\/strong\u003e 94\" x 28\" x 62\"\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eShipped Weight:\u003c\/strong\u003e 2,005 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\u003eAlternator Control:\u003c\/strong\u003e Standard on C3 configuration\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h2\u003e\n\u003cp\u003eWe have specialized in professional-grade shop compressors since 2016. A 30 HP duplex system at this price point deserves more than a web order — call us and we will walk through your shop's CFM requirements, discuss whether 120 or 240 gallons fits your usage pattern, review factory option packages, and confirm your electrical service can handle the load before you order. We have done this for shops of every size and we give straight answers.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFree Shipping\u003c\/strong\u003e on qualifying orders (freight delivery; call to confirm site requirements)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFree Technical Support\u003c\/strong\u003e — 866-217-0063, speak to someone who knows this equipment\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFull Manufacturer Warranty\u003c\/strong\u003e — Castair stands behind their duplex systems; we back it up\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHonest Configuration Guidance\u003c\/strong\u003e — if the 120-gallon tank is the wrong choice for your shop, we will tell you before you order\u003c\/li\u003e\n\u003c\/ul\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":53342538793173,"sku":"D15312HC3","price":29036.16,"currency_code":"USD","in_stock":true}],"url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-d15312hc3-s","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}