{"product_id":"castair-c3g","title":"Castair C3G","description":"\u003ch2\u003eCastair C3G Cast Iron Air Compressor Pump — Two-Stage W3 Cylinder (15HP)\u003c\/h2\u003e\n\u003cp\u003eThe Castair C3G is a heavy-duty two-stage cast iron bare pump built for 15HP compressor applications. It uses a W3 cylinder configuration with a 14-3B flywheel and holds 1.75 gallons of oil — distinguishing it from the standard C3 pump (which uses a 20.7-3B flywheel and 1-gallon oil capacity). The C3G is a replacement pump or a build-your-own compressor component, sold as a bare pump with flywheel. If you're replacing a worn pump in an existing 15HP compressor or building a custom unit on an existing tank, this is a Castair factory-direct component.\u003c\/p\u003e\n\n\u003ch2\u003eC3G vs. C3 — What's the Difference?\u003c\/h2\u003e\n\u003cp\u003eBoth the C3 and C3G are 15HP two-stage cast iron pumps in a W3 (3-cylinder configuration). The key differences:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFlywheel:\u003c\/strong\u003e C3G uses a 14-3B flywheel; the standard C3 uses a 20.7-3B flywheel\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOil capacity:\u003c\/strong\u003e C3G holds 1.75 gallons; C3 holds 1 gallon\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e Both weigh 485 lbs\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e The C3G is suited for configurations where the smaller flywheel diameter is required for the motor base geometry or belt drive layout\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIf you're replacing a C3G pump, match the flywheel spec carefully — a 14-3B versus 20.7-3B is a significant size difference that affects belt length, pulley alignment, and motor base positioning.\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 C3G\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 14-3B\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOil Capacity:\u003c\/strong\u003e 1.75 gallons\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\u003eCast Iron Pump Construction\u003c\/h2\u003e\n\u003cp\u003eCastair designs all of their C-series pumps for the same core principles: slow RPM operation for long life, all cast iron for thermal stability and durability, and disc-and-spring valves for reliable service access. The C3G is part of the same lineage as the C3 and C4 pumps used across Castair's industrial and commercial compressor lineup.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAll cast iron:\u003c\/strong\u003e Cylinders, heads, crankcase\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTwo-stage compression:\u003c\/strong\u003e W3 cylinder layout handles both low-pressure and high-pressure stages\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTapered roller bearings:\u003c\/strong\u003e Both ends of the crankshaft — superior crankshaft support and lower friction than ball bearings\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 Easy service access, high efficiency, good durability under high cycle counts\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e4-ring pistons:\u003c\/strong\u003e Improved sealing, less oil carry-over\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMechanical centrifugal unloader:\u003c\/strong\u003e Load-less start-up — standard on all Castair two-stage pumps\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWho Needs This Pump\u003c\/h2\u003e\n\u003cp\u003eThe C3G is a component sale — it's the right purchase for:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePump replacement:\u003c\/strong\u003e Your existing 15HP compressor uses a C3G pump and it needs rebuilding or replacement. At 485 lbs, this is a serious pump — plan for a hoist or engine crane for installation.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCustom compressor builds:\u003c\/strong\u003e You have an existing ASME tank and motor and want to build or restore a compressor around a Castair pump\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompressor rebuilders:\u003c\/strong\u003e Commercial shops that rebuild industrial compressors and need factory-fresh pump components\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIf you're not replacing an existing C3G pump and you need a complete compressor, you likely want one of Castair's assembled industrial units instead — the I15312VC3-S or I15312HC3-S are complete 15HP industrial compressors.\u003c\/p\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eThis is a bare pump with flywheel — does not include motor, tank, belt guard, pressure switch, or controls\u003c\/li\u003e\n  \u003cli\u003eOil must be added before operation — use Castair CAST-LUBE or equivalent compressor oil rated for piston compressors\u003c\/li\u003e\n  \u003cli\u003eChange break-in oil within the first 8 hours of operation\u003c\/li\u003e\n  \u003cli\u003eRequires compatible motor base, belt, and pulleys for your specific HP and RPM configuration\u003c\/li\u003e\n  \u003cli\u003eCentrifugal unloader requires a compatible pressure switch and unloader valve — confirm compatibility before installation\u003c\/li\u003e\n  \u003cli\u003eRight From the Start Kit #RFS002 includes break-in oil (GA30W), vibration pads (VP100 x4), ball valve, flex hose, and air filter element for C3 pump installations\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 OD\u003c\/th\u003e\n\u003cth\u003eOil Capacity\u003c\/th\u003e\n\u003cth\u003eWeight\u003c\/th\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\u003eC3\u003c\/td\u003e\n\u003ctd\u003e15\u003c\/td\u003e\n\u003ctd\u003eTwo\u003c\/td\u003e\n\u003ctd\u003eW3\u003c\/td\u003e\n\u003ctd\u003e20.7-3B\u003c\/td\u003e\n\u003ctd\u003e1 gal\u003c\/td\u003e\n\u003ctd\u003e485 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eC3G\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\u003e14-3B\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003e1.75 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\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, compressors, and components and have been supplying commercial and industrial air equipment since 2016. We can help you confirm the right pump for your application, match belt and pulley specs, and select correct oil and accessories 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":53342527979733,"sku":"C3G","price":0.0,"currency_code":"USD","in_stock":true}],"url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-c3g","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}