{"product_id":"castair-20hp-3-phase-industrial-air-compressor-horizontal-tank-w-mounted-starter-i20312hc4z-s","title":"Castair 20HP 3-Phase Industrial Air Compressor  Horizontal Tank w\/ Mounted Starter - I20312HC4Z-S","description":"\u003ch2\u003eCastair I20312HC4Z-S: 20HP 3-Phase Industrial Air Compressor — 120 Gallon Horizontal with Mounted Starter\u003c\/h2\u003e\n\n\u003cp\u003eThe Castair I20312HC4Z-S is a 20-horsepower, 3-phase, 120-gallon horizontal industrial air compressor built on Castair's heavy-duty C4 cast iron pump. The Z designation indicates this unit includes a factory-mounted magnetic motor starter — a meaningful distinction when you are doing a commercial installation and need a code-compliant, ready-to-wire setup rather than sourcing and mounting a separate starter panel.\u003c\/p\u003e\n\n\u003cp\u003eAt 20HP with the C4 pump, this is the entry point into Castair's large-frame compressor lineup. The C4 pump is a two-stage V4 cylinder design — four cylinders arranged in a V configuration — which gives it high volumetric efficiency and the capacity to deliver 72 CFM at 175 PSI. That is enough air to run 5-7 technicians simultaneously on standard shop tools, or to supply a moderate-size spray booth with adequate reserve.\u003c\/p\u003e\n\n\u003cp\u003eNote that this is the 120-gallon horizontal configuration. Castair also offers the 20HP with a 240-gallon horizontal tank (I20324HC4Z-S). The 120-gallon unit is appropriate when your peak demand is relatively consistent and your installation footprint limits tank size. If you regularly see high-demand spikes — running multiple spray guns or sandblasting while also supplying general shop air — step up to the 240-gallon.\u003c\/p\u003e\n\n\u003cp\u003e\u003cem\u003eManufacturer specifications are based on available Castair Industrial Series data. Contact us for current lead times and freight details on this model.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch2\u003ePump Design — C4 Cast Iron\u003c\/h2\u003e\n\n\u003ch3\u003eConstruction Details\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePump designation:\u003c\/strong\u003e C4 — Two-stage, V4 cylinder configuration (four cylinders in a V layout)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRated for:\u003c\/strong\u003e 15-25HP applications\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConstruction:\u003c\/strong\u003e 100% cast iron throughout — cylinders, heads, valve plates, crankcase\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlywheel:\u003c\/strong\u003e 13-3B configuration\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOil capacity:\u003c\/strong\u003e 1 gallon\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTapered roller bearings\u003c\/strong\u003e at 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 with automotive-type insert bearings at crankshaft and wrist pin\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDisc and spring valves\u003c\/strong\u003e for field serviceability and efficiency\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e4-ring pistons\u003c\/strong\u003e for high efficiency and low oil carry-over\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCentrifugal unloader\u003c\/strong\u003e — loadless start-up on every cycle protects the motor and drive system\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTank, Frame, and Controls\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTank capacity:\u003c\/strong\u003e 120 gallons, horizontal\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTank construction:\u003c\/strong\u003e Powder-coated ASME-rated steel with channel saddle frame\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSafety valve:\u003c\/strong\u003e ASME-rated, factory installed\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBelt guard:\u003c\/strong\u003e Totally enclosed metal\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDischarge lines:\u003c\/strong\u003e Copper tubing or stainless braided flex line\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMotor starter:\u003c\/strong\u003e Factory-mounted magnetic motor starter (Z designation) — code-compliant, wired and ready for power connection\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eMotor\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHorsepower:\u003c\/strong\u003e 20HP\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePhase:\u003c\/strong\u003e 3-phase (requires proper 3-phase service and appropriate breaker sizing)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMotor speed:\u003c\/strong\u003e 1725 RPM industrial\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eService factor:\u003c\/strong\u003e 15% minimum\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMax working pressure:\u003c\/strong\u003e 175 PSI\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePerformance Specifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMotor output:\u003c\/strong\u003e 20 HP\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eElectrical:\u003c\/strong\u003e 3-phase with factory-mounted starter\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTank capacity:\u003c\/strong\u003e 120 gallons, horizontal\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePump:\u003c\/strong\u003e C4 (Two-stage, V4 cylinder)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePump RPM:\u003c\/strong\u003e 519\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree air delivery (0 PSI):\u003c\/strong\u003e 92.8 CFM\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDelivery at 175 PSI:\u003c\/strong\u003e 72 CFM\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMax pressure:\u003c\/strong\u003e 175 PSI\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMotor starter:\u003c\/strong\u003e Factory mounted magnetic starter\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003eDimensions and weight: Contact us for current shipping specs on this model — dimensional data for the 120-gallon C4 configuration is pending manufacturer confirmation.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch2\u003eWhat's in the Box\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eCastair I20312HC4Z-S compressor — fully assembled\u003c\/li\u003e\n\u003cli\u003eFactory-mounted magnetic motor starter (Z designation)\u003c\/li\u003e\n\u003cli\u003eASME safety valve (factory installed)\u003c\/li\u003e\n\u003cli\u003ePressure switch with unloader\u003c\/li\u003e\n\u003cli\u003eTotally enclosed metal belt guard\u003c\/li\u003e\n\u003cli\u003eCopper discharge and unloader tubing (or stainless braided flex line)\u003c\/li\u003e\n\u003cli\u003eOwner's documentation\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003eAftercooler is not included in base configuration. Available as factory option (BGAC3M). Electrical connection to 3-phase service by customer\/electrician.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch2\u003eAvailable Configurations — 20HP Industrial Series\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eI20312HC4Z-S (this unit):\u003c\/strong\u003e 20HP, 3-phase, 120gal Horizontal, C4 pump, 519 RPM, 72 CFM @ 175 PSI, with mounted starter\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eI20324HC4Z-S:\u003c\/strong\u003e 20HP, 3-phase, 240gal Horizontal, C4 pump, 519 RPM, 72 CFM @ 175 PSI, 90x39x70, 1,700 lbs — same pump, double the tank storage\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eBoth units use the identical C4 pump and deliver the same CFM. The difference is tank storage capacity. The 240-gallon tank provides significantly more buffering for high-demand spikes. If your operation has variable demand — busy periods with multiple simultaneous users — the 240-gallon tank lets the compressor run fewer cycles and recover more quickly after heavy draw-down periods.\u003c\/p\u003e\n\n\u003ch2\u003eWhen Does a Shop Need This?\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eYou need 72 CFM at 175 PSI for a multi-bay shop, spray booth, or continuous-duty industrial process\u003c\/li\u003e\n\u003cli\u003eYour shop has 3-phase electrical service available\u003c\/li\u003e\n\u003cli\u003eYou need a factory-mounted starter for code compliance or simplified installation\u003c\/li\u003e\n\u003cli\u003eYour demand profile is consistent enough that 120 gallons of tank storage is adequate (versus the 240-gallon model)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eStep up to the 240-gallon (I20324HC4Z-S) if:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eYour shop sees high-demand spikes with multiple high-CFM tools running simultaneously — larger tank storage reduces compressor cycling and extends motor and pump life during heavy use periods\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eStep up to the 25HP (I25312HC4Z-S or I25324HC4Z-S) if:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eYour continuous demand regularly exceeds 72 CFM at pressure — the 25HP delivers 90 CFM at 175 PSI from the same C4 platform\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h2\u003e\n\u003cp\u003eSince 2016, we have specialized in industrial air compressors for shops, production facilities, and commercial operations. We understand the C4 pump platform, can help you size tank capacity to your actual demand profile, and can advise on electrical requirements before you commit to this purchase.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree shipping\u003c\/strong\u003e to commercial addresses in the lower 48 states\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree tech support\u003c\/strong\u003e at 866-217-0063 before and after your purchase\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eFull Castair manufacturer warranty\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHonest configuration guidance\u003c\/strong\u003e — we help you get the right tank size and options\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAuthorized dealer\u003c\/strong\u003e with direct Castair factory support\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":53342561403093,"sku":"I20312HC4Z-S","price":0.0,"currency_code":"USD","in_stock":true}],"url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-20hp-3-phase-industrial-air-compressor-horizontal-tank-w-mounted-starter-i20312hc4z-s","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}