{"product_id":"castair-6304","title":"Castair 6304","description":"\u003ch2\u003eCastair 6304 Low Oil Control Assembly\u003c\/h2\u003e\n\n\u003cp\u003eThe Castair 6304 is a low oil level protection control for Cast Air oil-lubricated air compressor pumps. Its job is simple and critical: if the crankcase oil level drops below the safe operating threshold, the 6304 interrupts the circuit and shuts the compressor down before the pump runs dry. A compressor that runs dry will destroy rod bearings, wrist pin bushings, and crankshaft journals within minutes. This control is inexpensive insurance against a failure mode that totals the pump.\u003c\/p\u003e\n\n\u003cp\u003eThe 6304 is the base standalone unit — the complete low oil control assembly sold for field installation or replacement. It is distinct from the 6304M, which is the factory-mounted version installed on motors at the assembly level, and the 6304x2M, which is a duplex pair for two-pump systems. If you are replacing a failed low oil control on a single-pump Cast Air compressor in the field, the 6304 is the part you want.\u003c\/p\u003e\n\n\u003ch3\u003eHow It Works\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFloat-actuated switch:\u003c\/strong\u003e A float inside the housing rides on the oil surface. When the oil level drops below the set point, the float falls and opens the circuit.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNormally closed circuit:\u003c\/strong\u003e The switch is closed during normal operation. An open circuit (low oil) triggers shutdown — this is the fail-safe orientation. A wiring failure also results in shutdown, not runaway operation.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDirect wiring into the motor circuit:\u003c\/strong\u003e The 6304 wires in series with the motor control circuit. No relay required for standard single-pump installations.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMounts to the crankcase:\u003c\/strong\u003e Threaded fitting installs into the crankcase at the correct oil-level reference point.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhere the 6304 Fits in the Castair Low Oil Control Lineup\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e6304 (this part):\u003c\/strong\u003e Standalone assembly. Single-pump field replacement or retrofit installation.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e6304M:\u003c\/strong\u003e Factory-mounted version. Installed on the motor at the factory. If your motor came with a low oil control from the factory, it shipped with the 6304M configuration.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e6304x2M:\u003c\/strong\u003e Two 6304 controls in a factory-mounted duplex configuration. Used on two-pump tandem systems where both pumps need independent low oil protection.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhy Low Oil Protection Matters on Cast Air Pumps\u003c\/h3\u003e\n\u003cp\u003eCast Air builds their pumps from cast iron for long service life. The slow-speed design — most Cast Air pumps run at 600–1,000 RPM at the pump — keeps operating temperatures low and extends component life significantly compared to high-speed aluminum pumps. But that durability depends entirely on continuous oil lubrication. The splash lubrication system in a cast iron pump delivers oil to the rod bearings, wrist pin, and cylinder walls via the rotation of the crankshaft dipping into the oil reservoir. If the reservoir runs dry, lubrication stops immediately and the metal-to-metal contact destroys the bearings within a few minutes of operation.\u003c\/p\u003e\n\n\u003cp\u003eThe typical causes of low oil in a Cast Air pump are:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFailed crankcase gasket or seal:\u003c\/strong\u003e Slow leak that drains the reservoir over days or weeks.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOverfill followed by blowby loss:\u003c\/strong\u003e Excess oil carried past the rings and into the discharge air.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eExtended service interval without oil check:\u003c\/strong\u003e Oil gets dirty, viscosity breaks down, and level drops without the operator noticing.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCracked crankcase:\u003c\/strong\u003e Rare, but it happens. The 6304 catches it before it becomes catastrophic.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eIn a shop environment where the compressor runs unattended — overnight, through a shift change, or in a back room — the low oil control is the only thing standing between a slow leak and a destroyed pump. The cost of the 6304 is a fraction of a crankshaft or connecting rod replacement, let alone a full pump rebuild.\u003c\/p\u003e\n\n\u003ch3\u003eInstallation Notes\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eThreaded crankcase fitting — confirm thread size and port location on your specific pump model before ordering.\u003c\/li\u003e\n  \u003cli\u003eWire in series with the motor start circuit. The compressor will not start if the oil level is below the set point, which also provides a pre-start check.\u003c\/li\u003e\n  \u003cli\u003eTest after installation: drain oil slightly below the set point and confirm the switch opens and the motor will not start. Refill to the correct level and confirm normal operation resumes.\u003c\/li\u003e\n  \u003cli\u003eIf you are replacing a failed unit, inspect the crankcase port for damage or debris before installing the new control.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSpecification Note\u003c\/h3\u003e\n\u003cp\u003eCastair does not publish detailed dimensional specifications for the 6304 standalone assembly on their public catalog pages — mounting dimensions, thread size, and electrical ratings are confirmed at the time of order. Call 866-217-0063 with your pump model number and we will confirm compatibility before you order.\u003c\/p\u003e\n\n\u003ch3\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCast Air specialists:\u003c\/strong\u003e We know the lineup and can confirm which low oil control fits your pump model and installation scenario — standalone 6304, motor-mounted 6304M, or duplex 6304x2M.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFree shipping\u003c\/strong\u003e on qualifying orders.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFree technical support:\u003c\/strong\u003e Call 866-217-0063. We can walk you through installation wiring if needed.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGenuine Cast Air parts:\u003c\/strong\u003e OEM assemblies built for Cast Air compressors — not generic float switches.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHonest guidance:\u003c\/strong\u003e If the 6304 is not the right part for your installation, we will tell you that and point you to the correct one.\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":53342510416085,"sku":"6304","price":144.84,"currency_code":"USD","in_stock":true}],"url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-6304","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}