{"product_id":"castair-refrigerated-dryer-accessory-rdd40sv","title":"Castair Refrigerated Dryer Accessory - RDD40SV","description":"\u003cp\u003eThe Castair RDD40SV is the solenoid valve replacement part for the RDD40 refrigerated compressed air dryer. The automatic demand drain on a Castair refrigerated dryer is controlled by a solenoid valve — it opens to eject condensate when liquid is detected and closes immediately after, without bleeding compressed air unnecessarily. When this solenoid fails, the dryer either loses its automatic drain function entirely (moisture starts passing through) or the drain stays open continuously (constant air loss and noise). The RDD40SV replaces that solenoid valve directly.\u003c\/p\u003e\n\n\u003cp\u003eThis is a standard service part for RDD40 series dryers in regular shop service. Solenoid valves wear out — coil insulation breaks down over time, the plunger develops wear, or internal seals fail. In high-cycle environments where the compressor runs frequently and the dryer drain is operating dozens of times per hour, solenoid replacement every few years is normal maintenance, not a failure event.\u003c\/p\u003e\n\n\u003ch2\u003eSymptoms of a Failed Drain Solenoid\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eContinuous air bleed from the drain:\u003c\/strong\u003e Solenoid is stuck open — valve plunger or seat is worn, or the coil is shorted. Replace the solenoid valve.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo drainage, moisture at tools:\u003c\/strong\u003e Solenoid is stuck closed — coil burned out or plunger seized. The dryer is chilling the air but cannot eject the condensate, so it re-evaporates back into the airstream downstream.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIntermittent drainage:\u003c\/strong\u003e Coil is marginal, plunger is sluggish — replace before it fails completely.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSolenoid buzzing or overheating:\u003c\/strong\u003e Coil failure in progress. Replace immediately.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDirect replacement:\u003c\/strong\u003e OEM Castair solenoid valve for the RDD40 dryer drain circuit\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDemand-drain design:\u003c\/strong\u003e Valve only opens when condensate is detected — conserves compressed air vs. timer-based drains\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication-specific:\u003c\/strong\u003e Matched to the RDD40 drain circuit voltage and flow requirements\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhat's in the Box\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eCastair RDD40SV replacement solenoid valve for RDD40 refrigerated dryer\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003eNote: Installation requires basic electrical and pneumatic disassembly skills. Depressurize the dryer and disconnect power before replacing. Contact us at 866-217-0063 for installation guidance.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch2\u003eCompatible Equipment\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eCastair RDD40 series refrigerated compressed air dryers\u003c\/li\u003e\n\u003cli\u003eConfirm with your unit model and serial number — call 866-217-0063 before ordering if unsure\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 RDD40SV\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Castair (Cast Air, Inc.)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Castair RDD40 refrigerated compressed air dryer, drain circuit\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eComponent type:\u003c\/strong\u003e Solenoid valve\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eElectrical specifications:\u003c\/strong\u003e Contact us for coil voltage and wiring details — 866-217-0063\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h3\u003e\n\u003cp\u003eWe carry Castair service parts and can help you identify the correct solenoid for your RDD40 dryer. If you are troubleshooting a drain problem and are not certain which component has failed, call us before ordering — we can walk through the diagnosis with you. Free shipping on qualifying orders, free pre-sale technical support, genuine Castair parts.\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":53342593876181,"sku":"RDD40SV","price":2747.7,"currency_code":"USD","in_stock":true}],"url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-refrigerated-dryer-accessory-rdd40sv","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}