{"product_id":"castair-c4-cast-iron-air-compressor-pump-20-30hp-c4z","title":"Castair C4 Cast Iron Air Compressor Pump (20-30HP) - C4Z","description":"\u003ch2\u003eCastair C4 Cast Iron Air Compressor Pump — 20-30HP Two-Stage V4 (C4Z)\u003c\/h2\u003e\n\u003cp\u003eThe Castair C4Z is the top of Castair's bare pump lineup — a two-stage, all-cast-iron V4-cylinder pump designed for 15-25HP applications. At 800 lbs, this is a serious piece of equipment. It uses a 13-3B flywheel and holds 1 gallon of oil. The C4 pump is what Castair puts in their largest industrial compressor units — the 20HP, 25HP, and 30HP machines in the I-series. If you're replacing the pump in one of those units or building a high-HP custom compressor, the C4Z is the Castair factory-direct component.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eNote on HP rating:\u003c\/strong\u003e Castair lists the C4 as rated for 15-25HP in their published pump table, but the C4Z SKU in our database lists 20-30HP — consistent with the C4's use in Castair's 20HP, 25HP, and 30HP industrial compressor models (I20324HC4-S through I30324HC4Z-S). Contact us to confirm the right HP match for your application.\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 C4 \/ C4Z\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHorsepower Rating:\u003c\/strong\u003e 15-25HP (factory table) \/ 20-30HP (per model application)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 800 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 V4 (four-cylinder V configuration)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFlywheel OD:\u003c\/strong\u003e 13-3B\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\u003eV4 Cylinder Configuration — What It Means\u003c\/h2\u003e\n\u003cp\u003eThe C4 uses a V4 cylinder layout — four cylinders arranged in two pairs at a V angle. In a two-stage pump, the large-bore cylinders handle the first stage (low-pressure) compression, and the smaller high-pressure cylinders handle the second stage. The V4 configuration provides balanced reciprocating forces across the pump, contributing to smoother operation at the slow RPM that Castair designs for. At 800 lbs, this pump runs in the same category as industrial screw compressor components in terms of mass and thermal stability.\u003c\/p\u003e\n\n\u003ch2\u003eCast Iron Pump Construction\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAll cast iron:\u003c\/strong\u003e Cylinders, heads, crankcase — full cast iron for thermal stability and long service life\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTwo-stage V4 compression:\u003c\/strong\u003e Four cylinders handling both compression stages\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSlow RPM design:\u003c\/strong\u003e In Castair's 20-30HP industrial compressors, the C4 pump runs at 519-794 RPM — very slow, very long-lived\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTapered roller bearings:\u003c\/strong\u003e Both ends of the crankshaft\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, efficient, reliable under sustained duty\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e4-ring pistons:\u003c\/strong\u003e Better compression efficiency, reduced oil carry-over\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCentrifugal unloader:\u003c\/strong\u003e Load-less start-up standard\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhere This Pump Is Used — Castair's 20-30HP Industrial Compressors\u003c\/h2\u003e\n\u003cp\u003eThe C4 pump is the heart of Castair's largest industrial piston compressors:\u003c\/p\u003e\n\u003ctable\u003e\n  \u003ctr\u003e\n\u003cth\u003eModel\u003c\/th\u003e\n\u003cth\u003eHP\u003c\/th\u003e\n\u003cth\u003ePhase\u003c\/th\u003e\n\u003cth\u003eTank\u003c\/th\u003e\n\u003cth\u003ePump RPM\u003c\/th\u003e\n\u003cth\u003eCFM @ 0 PSI\u003c\/th\u003e\n\u003cth\u003eCFM @ 175 PSI\u003c\/th\u003e\n\u003cth\u003eWeight\u003c\/th\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eI20324HC4-S\u003c\/td\u003e\n\u003ctd\u003e20\u003c\/td\u003e\n\u003ctd\u003e3\u003c\/td\u003e\n\u003ctd\u003e240-Gal Horiz.\u003c\/td\u003e\n\u003ctd\u003e519\u003c\/td\u003e\n\u003ctd\u003e92.8\u003c\/td\u003e\n\u003ctd\u003e72\u003c\/td\u003e\n\u003ctd\u003e1,700 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eI25324HC4-S\u003c\/td\u003e\n\u003ctd\u003e25\u003c\/td\u003e\n\u003ctd\u003e3\u003c\/td\u003e\n\u003ctd\u003e240-Gal Horiz.\u003c\/td\u003e\n\u003ctd\u003e710\u003c\/td\u003e\n\u003ctd\u003e109\u003c\/td\u003e\n\u003ctd\u003e90\u003c\/td\u003e\n\u003ctd\u003e1,725 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003eI30324HC4Z-S\u003c\/td\u003e\n\u003ctd\u003e30\u003c\/td\u003e\n\u003ctd\u003e3\u003c\/td\u003e\n\u003ctd\u003e240-Gal Horiz.\u003c\/td\u003e\n\u003ctd\u003e794\u003c\/td\u003e\n\u003ctd\u003e128\u003c\/td\u003e\n\u003ctd\u003e105\u003c\/td\u003e\n\u003ctd\u003e1,750 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eWho Needs the C4Z Pump\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePump replacement:\u003c\/strong\u003e Your existing 20-30HP Castair industrial compressor needs a new pump — the C4Z is the factory replacement component\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCustom high-HP builds:\u003c\/strong\u003e You have a large ASME tank (240-gallon is standard for this pump class), a 20-30HP three-phase industrial motor, and are building or restoring a compressor\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIndustrial compressor rebuilders:\u003c\/strong\u003e Shops that overhaul large commercial and industrial compressor equipment\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAt 800 lbs, installation requires heavy lifting equipment. This is not a pump you handle with a hand truck — plan for a crane or forklift during installation.\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 oil before operation — 1-gallon capacity\u003c\/li\u003e\n  \u003cli\u003eBreak-in oil change required within the first 8 hours of operation\u003c\/li\u003e\n  \u003cli\u003eRight From the Start Kit #RFS003 is recommended for C4 pump installations\u003c\/li\u003e\n  \u003cli\u003eRequires compatible 20-30HP industrial motor, motor base, belt, and pulleys\u003c\/li\u003e\n  \u003cli\u003eCentrifugal unloader requires compatible pressure switch and unloader plumbing\u003c\/li\u003e\n  \u003cli\u003eAvailable factory option: All Options C4 (#AOC4) — bundles all asterisk factory options at 10% savings\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\u003eCylinders\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\u003eC2\u003c\/td\u003e\n\u003ctd\u003e7.5-10\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\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\u003eC3G\u003c\/td\u003e\n\u003ctd\u003e15\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\u003e\u003cstrong\u003eC4 \/ C4Z\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003e15-25\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eV4\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003e13-3B\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003e1 gal\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003e800 lbs\u003c\/strong\u003e\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 industrial compressor components and have been supplying commercial and industrial air equipment since 2016. We can help you match the C4Z pump to your motor, motor base, belt and pulleys, and confirm the accessories you need. 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":53342528340181,"sku":"C4Z","price":12396.6,"currency_code":"USD","in_stock":true}],"url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-c4-cast-iron-air-compressor-pump-20-30hp-c4z","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}