{"product_id":"castair-check-valve-assembly-075-36-va075-36","title":"Castair Check Valve Assembly 075-36 - VA075-36","description":"\u003cp\u003eThe Castair VA075-36 is a check valve assembly for Castair air compressor systems. The check valve sits between the pump discharge and the tank, and its job is straightforward but critical: it lets compressed air flow into the tank and prevents it from flowing back out through the pump when the motor shuts off. If your check valve fails, you'll see symptoms immediately — the compressor motor strains on restart because it's trying to start against full tank pressure, pressure bleeds back through the pump when the compressor stops, or the unloader valve doesn't relieve properly. The VA075-36 is the Castair OEM replacement for this assembly.\u003c\/p\u003e\n\n\u003ch2\u003eHow a Check Valve Works and Why It Fails\u003c\/h2\u003e\n\u003cp\u003eThe check valve is a one-way valve — spring-loaded or ball-type — that opens under pump discharge pressure and closes under tank back-pressure. Every time the compressor shuts off, this valve closes and holds tank pressure on the tank side, while the pump side bleeds down through the unloader. When the check valve fails internally:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eTank air leaks back through the pump, causing the motor to restart under load\u003c\/li\u003e\n\u003cli\u003eMotor trips thermal overload protection on restart due to the back-pressure load\u003c\/li\u003e\n\u003cli\u003eCompressor pressure drops slowly when the motor is off, even without any air draw\u003c\/li\u003e\n\u003cli\u003eUnloader valve may not work properly if back-pressure timing is off\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eA failed check valve is one of the more common wear items on a piston compressor. The seating surface wears, debris from the pump can damage the seat, and old oil varnish can cause the valve to stick open. Replacing the entire assembly (rather than just the internal valve element) is the cleaner repair when the body shows wear.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Castair Assembly:\u003c\/strong\u003e Factory-specification check valve for Castair compressor systems\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eComplete Assembly:\u003c\/strong\u003e Full check valve assembly including body and internal valve components\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSized for the Application:\u003c\/strong\u003e The \"075\" designation refers to 3\/4\" connection sizing — verify your compressor's check valve port size before ordering\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrevents Back-Flow:\u003c\/strong\u003e Maintains tank pressure when pump is not running\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEnables Proper Unloader Function:\u003c\/strong\u003e The check valve and unloader valve work as a system — the check valve must function correctly for the unloader to do its job\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eDiagnosing Check Valve Failure\u003c\/h2\u003e\n\u003cp\u003eBefore ordering a replacement, verify the check valve is the problem:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRestart Test:\u003c\/strong\u003e With a full tank, shut off the compressor and listen. If you hear air hissing from the unloader line continuously after the motor stops and the unloader has cycled, back-pressure from a leaking check valve may be the cause\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePressure Drop Test:\u003c\/strong\u003e With no air tools running and the compressor off, watch the tank gauge over 15-30 minutes. Significant pressure drop indicates either a leaking check valve, tank fitting leak, or safety valve leak — check the obvious first\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRestart Under Pressure:\u003c\/strong\u003e If the motor trips or struggles to restart with a pressurized tank, and the unloader is working correctly, suspect the check valve allowing back-pressure to the pump\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhat's in the Box\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e1x Castair VA075-36 Check Valve Assembly\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003eNote: Manufacturer product page data was not available at time of writing. Internal valve type, pressure rating, and exact fitting thread specifications are not confirmed from manufacturer data. Contact us to confirm compatibility with your Castair model before ordering.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eDepressurize the tank completely before removing the old check valve — this is a safety requirement, not a suggestion\u003c\/li\u003e\n\u003cli\u003eNote the orientation of the old check valve before removal — the arrow indicating flow direction must point toward the tank\u003c\/li\u003e\n\u003cli\u003eUse thread sealant (not tape) on NPT threads to prevent leaks at the fitting\u003c\/li\u003e\n\u003cli\u003eTorque to manufacturer specification — overtightening NPT fittings in cast iron bodies cracks the body\u003c\/li\u003e\n\u003cli\u003eRun the compressor and check for leaks at both fittings after installation\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e VA075-36\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Cast Air \/ Castair\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConnection Size:\u003c\/strong\u003e 3\/4\" (075 designation)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCategory:\u003c\/strong\u003e Major Components — Valves\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Check Valve Assembly\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003ePressure rating, internal valve configuration, and thread specifications were not confirmed from manufacturer data at time of writing. Call us for full specs before ordering.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch3\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCastair Specialist:\u003c\/strong\u003e We stock Castair valve components and can help confirm the correct part number for your compressor model\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree Shipping:\u003c\/strong\u003e On qualifying orders to the contiguous US\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree Tech Support:\u003c\/strong\u003e Call 866-217-0063 — check valve diagnosis and replacement is something we walk through regularly\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Parts:\u003c\/strong\u003e Castair factory-specification replacements, not generic substitutes\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFull Manufacturer Warranty:\u003c\/strong\u003e Covered under Castair's standard parts warranty\u003c\/li\u003e\n\u003c\/ul\u003e\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":53342609440981,"sku":"VA075-36","price":195.96,"currency_code":"USD","in_stock":true}],"url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-check-valve-assembly-075-36-va075-36","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}