{"product_id":"castair-psl4mix","title":"Castair PSL4MIX","description":"\u003cp\u003eThe Castair PSL4MIX is the top-configuration pressure switch in the 95-125 PSI range. It includes an integrated unloader valve, a manual on\/off lever, and a four-way valve port arrangement. This is the switch for duplex compressor setups, multi-head pump configurations, or any system where the unloader needs to vent to multiple points. If your system uses standard single-port plumbing, the PSL1X or PSL1MIX is the correct choice — the PSL4MIX is for systems specifically designed for four-way operation.\u003c\/p\u003e\n\n\u003ch2\u003eFour-Way Valve Configuration — What It Means in Practice\u003c\/h2\u003e\n\u003cp\u003eThe four-way configuration provides additional unloader ports beyond the standard single-port PSL1X. On a duplex compressor running two pump heads from one shared tank and one pressure switch, the four-way allows both pump heads to unload simultaneously at shutdown. Both motors then restart unloaded on the next pressure cycle. This is critical on two-pump systems — if only one pump head unloads, the other motor starts against head pressure, burning through start capacitors on that side. The PSL4MIX solves this with a single switch that handles both unload paths.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOperating range:\u003c\/strong\u003e 95 PSI cut-in \/ 125 PSI cut-out\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUnloader valve:\u003c\/strong\u003e Included with four-way configuration\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOn\/Off lever:\u003c\/strong\u003e Manual lever for controlled shutdown\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFour-way valve ports:\u003c\/strong\u003e Multiple unloader connections for duplex or complex plumbing\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCorrosion resistant cover:\u003c\/strong\u003e Shop-grade protection\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUL\/CSA listed:\u003c\/strong\u003e Commercial electrical safety certification\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eFull Lineup — 95-125 PSI Pressure Switches\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePSL1\u003c\/strong\u003e — No unloader, no on\/off\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePSL1X\u003c\/strong\u003e — With unloader, no on\/off\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePSL1MIX\u003c\/strong\u003e — With unloader and on\/off\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePSL4MIX\u003c\/strong\u003e — With unloader, on\/off, and four-way valve (this unit)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eHigh-pressure (145-175 PSI) equivalent is the PSH4MIX.\u003c\/p\u003e\n\n\u003ch2\u003eWhen Do You Need the PSL4MIX?\u003c\/h2\u003e\n\u003cp\u003eOrder the PSL4MIX when your compressor has multiple pump heads sharing one pressure switch, or when the existing plumbing has a four-port manifold at the switch connection. If you are replacing a single-pump compressor switch, you are ordering more than you need — use the PSL1MIX. If you are not sure how many unloader ports your existing switch has, count the copper or brass tubes running from the switch body back to the pump heads. One tube means PSL1X or PSL1MIX; multiple tubes means PSL4MIX.\u003c\/p\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e PSL4MIX\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Castair (Cast Air)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePressure range:\u003c\/strong\u003e 95-125 PSI\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUnloader valve:\u003c\/strong\u003e Yes, four-way configuration\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOn\/Off switch:\u003c\/strong\u003e Yes, manual lever\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCertifications:\u003c\/strong\u003e UL\/CSA listed\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCover:\u003c\/strong\u003e Corrosion resistant\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 PSL4MIX pressure switch with four-way unloader valve and on\/off lever\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h3\u003e\n\u003cp\u003eWe stock specialty Castair components including the four-way switch configurations that most general suppliers do not carry. If you are building or servicing a duplex compressor system, call us — we can help you confirm the correct switch and verify availability. Free shipping on qualifying orders.\u003c\/p\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":53342575263957,"sku":"PSL4MIX","price":89.46,"currency_code":"USD","in_stock":true}],"url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-psl4mix","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}