{"product_id":"castair-15-hp-2-stage-iron-bare-pump-with-flywheel-cylinder-w3-c3","title":"Castair 15 HP 2 Stage Iron Bare Pump With Flywheel Cylinder W3 C3","description":"\u003ch2\u003eCastair C3 Cast Iron Air Compressor Pump — 15HP Two-Stage W3 with Flywheel\u003c\/h2\u003e\n\u003cp\u003eThe Castair C3 is a two-stage cast iron bare pump designed for 15HP applications. It uses a W3 (three-cylinder) configuration with a 20.7-3B flywheel and holds 1 gallon of oil. At 485 lbs, this is a heavy-duty industrial pump — it's the foundation for Castair's 15HP industrial compressor units and is sold as a replacement pump or component for custom compressor builds. The price point ($3,715.25) reflects what you're getting: a full cast iron industrial pump, not a light-duty commercial unit.\u003c\/p\u003e\n\n\u003ch2\u003ePump Specifications — From Castair's Published Data\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e C3\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHorsepower Rating:\u003c\/strong\u003e 15HP\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 485 lbs\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompression Stages:\u003c\/strong\u003e Two-stage\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCylinder Configuration:\u003c\/strong\u003e W3 (three-cylinder)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFlywheel OD:\u003c\/strong\u003e 20.7-3B\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOil Capacity:\u003c\/strong\u003e 1 gallon\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 1 year parts only, when properly installed and maintained\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eC3 vs. C3G — Choosing the Right 15HP Pump\u003c\/h2\u003e\n\u003cp\u003eCastair offers two 15HP W3 pumps. The key difference is flywheel size and oil capacity:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eC3:\u003c\/strong\u003e 20.7-3B flywheel, 1-gallon oil capacity, 485 lbs — larger flywheel diameter for standard motor base configurations\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eC3G:\u003c\/strong\u003e 14-3B flywheel, 1.75-gallon oil capacity, 485 lbs — smaller flywheel for configurations where the larger diameter won't fit the belt drive geometry\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIf you're replacing an existing pump, match the flywheel specification exactly. The flywheel OD determines belt length and pulley alignment. A wrong flywheel spec means re-engineering the entire drive system.\u003c\/p\u003e\n\n\u003ch2\u003eCast Iron Pump Construction\u003c\/h2\u003e\n\u003cp\u003eCastair's C-series pumps share a common design philosophy: all cast iron, slow RPM, and precision machined internal components. The C3 is the same pump used in Castair's 15HP industrial compressor units (I15312VC3-S, I15312HC3-S).\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAll cast iron:\u003c\/strong\u003e Cylinders, heads, crankcase — full cast iron throughout\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eW3 three-cylinder layout:\u003c\/strong\u003e Three cylinders in a W configuration — two low-pressure, one high-pressure — handling both compression stages\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTapered roller bearings:\u003c\/strong\u003e Both ends of the crankshaft for superior support and reduced friction\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePrecision steel connecting rods:\u003c\/strong\u003e Automotive-type rod insert bearings at crankshaft, needle bearings at wrist pin\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDisc and spring valves:\u003c\/strong\u003e Service-friendly design, high efficiency, reliable under sustained cycling\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e4-ring pistons:\u003c\/strong\u003e Better sealing efficiency, reduced oil carry-over into compressed air\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMechanical centrifugal unloader:\u003c\/strong\u003e Load-less start — the motor starts unloaded and compression begins as RPM builds\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSlow RPM design:\u003c\/strong\u003e Castair's C3 runs at 795-898 RPM in their assembled compressor lineup — this slow speed is what gives the pump its long service life and quiet operation\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWho Needs This Pump\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePump replacement:\u003c\/strong\u003e Your existing 15HP industrial compressor uses a C3 pump — the pump needs replacement or overhaul and you want a factory-new unit versus a rebuild\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCustom compressor builds:\u003c\/strong\u003e You have an existing ASME tank (120-gallon or larger is typical for 15HP industrial use) and a 15HP industrial motor and are building or restoring a compressor\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eEquipment dealers and rebuilders:\u003c\/strong\u003e Shops that service and rebuild commercial and industrial compressors\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIf you need a complete assembled 15HP compressor, the Castair I15312VC3-S (vertical, 120-gallon, 61.7 CFM @ 0 PSI, 50.2 CFM @ 175 PSI, 1,185 lbs) or I15312HC3-S (horizontal equivalent) are complete factory-built units.\u003c\/p\u003e\n\n\u003ch2\u003eInstallation Requirements\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eBare pump with flywheel — does not include motor, tank, belt guard, pressure switch, or controls\u003c\/li\u003e\n  \u003cli\u003eFill with Castair CAST-LUBE compressor oil before first operation — break-in oil change required within the first 8 hours\u003c\/li\u003e\n  \u003cli\u003eRight From the Start Kit #RFS002 is recommended — includes break-in oil (2x GA30W gallon), vibration pads, ball valve, flex hose, and air filter elements\u003c\/li\u003e\n  \u003cli\u003eRequires compatible motor, motor base, belt, and pulleys for your specific RPM and drive configuration\u003c\/li\u003e\n  \u003cli\u003eCentrifugal unloader requires a compatible pressure switch and unloader plumbing\u003c\/li\u003e\n  \u003cli\u003eAt 485 lbs, you need a hoist, engine crane, or forklift for installation\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eRelated Castair Pump Models\u003c\/h2\u003e\n\u003ctable\u003e\n  \u003ctr\u003e\n\u003cth\u003ePart #\u003c\/th\u003e\n\u003cth\u003eHP\u003c\/th\u003e\n\u003cth\u003eStage\u003c\/th\u003e\n\u003cth\u003eCylinder\u003c\/th\u003e\n\u003cth\u003eFlywheel\u003c\/th\u003e\n\u003cth\u003eOil Cap.\u003c\/th\u003e\n\u003cth\u003eWeight\u003c\/th\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eC1\u003c\/td\u003e\n\u003ctd\u003e4-7.5\u003c\/td\u003e\n\u003ctd\u003eTwo\u003c\/td\u003e\n\u003ctd\u003eInline 2\u003c\/td\u003e\n\u003ctd\u003e16.875-2B\u003c\/td\u003e\n\u003ctd\u003e2 qt\u003c\/td\u003e\n\u003ctd\u003e225 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eC2\u003c\/td\u003e\n\u003ctd\u003e7.5-10\u003c\/td\u003e\n\u003ctd\u003eTwo\u003c\/td\u003e\n\u003ctd\u003eV4\u003c\/td\u003e\n\u003ctd\u003e19.0-2B\u003c\/td\u003e\n\u003ctd\u003e2 qt\u003c\/td\u003e\n\u003ctd\u003e320 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eC3\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003e15\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eTwo\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eW3\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003e20.7-3B\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003e1 gal\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003e485 lbs\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eC3G\u003c\/td\u003e\n\u003ctd\u003e15\u003c\/td\u003e\n\u003ctd\u003eTwo\u003c\/td\u003e\n\u003ctd\u003eW3\u003c\/td\u003e\n\u003ctd\u003e14-3B\u003c\/td\u003e\n\u003ctd\u003e1.75 gal\u003c\/td\u003e\n\u003ctd\u003e485 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eC4\u003c\/td\u003e\n\u003ctd\u003e15-25\u003c\/td\u003e\n\u003ctd\u003eTwo\u003c\/td\u003e\n\u003ctd\u003eV4\u003c\/td\u003e\n\u003ctd\u003e13-3B\u003c\/td\u003e\n\u003ctd\u003e1 gal\u003c\/td\u003e\n\u003ctd\u003e800 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h2\u003e\n\u003cp\u003eWe stock Castair pumps and have been supplying commercial and industrial air equipment since 2016. We can help you match this pump to your motor, motor base, belt and pulleys, and confirm the oil and accessories you'll need for installation. Free shipping on qualifying orders. Free tech support at 866-217-0063. Full manufacturer warranty.\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":53342527226069,"sku":"C3","price":6851.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0622\/8466\/0949\/files\/CAST-IRON-BARE-PUMPS-WITH-FLYWHEEL_new_09bbb062-aa90-4971-ba96-92b4e1294af0.jpg?v=1772652604","url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-15-hp-2-stage-iron-bare-pump-with-flywheel-cylinder-w3-c3","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}