{"product_id":"castair-pressure-switch-145-175-psi-on-off-no-unloader-psh1","title":"Castair Pressure Switch 145-175 PSI On\/Off no unloader PSH1","description":"\u003cp\u003eThe Castair PSH1 is a pressure switch for Cast Air air compressors, set to operate in the 145-175 PSI range with on\/off control and no integral unloader valve. At $36.31, this is the standard-range pressure switch for Cast Air single-stage compressors operating at higher shop pressures (145 PSI cut-in, 175 PSI cut-out) where an unloader valve is handled separately or is not required by the motor and drive system design.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eNote: Cast Air did not provide a dedicated manufacturer product page for this switch.\u003c\/strong\u003e Specifications are drawn from the product listing. Contact us to confirm electrical rating (voltage and amperage) and application compatibility before ordering.\u003c\/p\u003e\n\n\u003ch2\u003eWhat a Pressure Switch Does\u003c\/h2\u003e\n\u003cp\u003eThe pressure switch is the automatic control for the compressor motor. When tank pressure drops to the cut-in setting (145 PSI on the PSH1), the switch closes and the motor starts. When pressure reaches the cut-out setting (175 PSI), the switch opens and the motor stops. It does this automatically, cycling the compressor to maintain tank pressure within the set range without any manual intervention. When the pressure switch fails — either sticking open (compressor will not start) or sticking closed (compressor runs continuously) — the compressor becomes either non-functional or unsafe. The PSH1 is the OEM replacement.\u003c\/p\u003e\n\n\u003ch3\u003eSwitch Specification Details\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e PSH1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePressure Range:\u003c\/strong\u003e 145-175 PSI (cut-in 145 PSI \/ cut-out 175 PSI)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eControl Type:\u003c\/strong\u003e On\/Off\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUnloader:\u003c\/strong\u003e None\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Cast Air single-stage compressors running at 145-175 PSI tank pressure\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrice:\u003c\/strong\u003e $36.31\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eNo Unloader — When This Is the Correct Choice\u003c\/h2\u003e\n\u003cp\u003eThe PSH1 does not include an integral unloader valve. This matters at startup: when the compressor motor stops at the cut-out pressure, some compressed air remains in the pump head and the outlet line. When the motor restarts at cut-in pressure, it must start against that residual pressure — which adds to the startup torque load on the motor. For compressors where this is not a problem (capacitor-start motors, systems with a separate check valve that limits back-pressure, or applications where the line pressure drops naturally before the next start cycle), a no-unloader switch like the PSH1 is appropriate and simpler. If your motor struggles to restart — especially if it hums, trips the overload, or is slow to get up to speed — you need a switch with an unloader, like the PSH1MIX.\u003c\/p\u003e\n\n\u003ch2\u003eWhen Does a Shop Need the PSH1?\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eExisting pressure switch has failed (motor does not start when pressure drops, or runs continuously)\u003c\/li\u003e\n\u003cli\u003eReplacing a pressure switch on a Cast Air compressor that does not use an integral unloader valve\u003c\/li\u003e\n\u003cli\u003ePressure switch contacts are burned, corroded, or mechanically damaged\u003c\/li\u003e\n\u003cli\u003eCompressor is cutting out too early or too late — pressure switch set points have drifted\u003c\/li\u003e\n\u003cli\u003eThe 145-175 PSI range matches the application (for lower-pressure shop use, a 90-125 PSI switch is more appropriate)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003ePSH1 vs. PSH1MIX — Which Do You Need?\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePSH1 — 145-175 PSI, no unloader — $36.31\u003c\/strong\u003e (this unit) — correct when no unloader is needed or a separate unloader is in the system\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePSH1MIX — 145-175 PSI, with unloader and on\/off — $40.73\u003c\/strong\u003e — correct when the motor needs to restart against reduced head pressure; includes the integral unloader valve that vents the head at shutoff\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eIf you are not sure whether your application requires an unloader, call us. We can identify the correct switch based on your compressor model and motor type.\u003c\/p\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e PSH1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Cast Air (Castair)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCut-In Pressure:\u003c\/strong\u003e 145 PSI\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCut-Out Pressure:\u003c\/strong\u003e 175 PSI\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDifferential:\u003c\/strong\u003e 30 PSI (fixed)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUnloader:\u003c\/strong\u003e None\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eElectrical Rating:\u003c\/strong\u003e Not confirmed in listing — call to verify voltage and amperage rating for your motor\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrice:\u003c\/strong\u003e $36.31\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Data:\u003c\/strong\u003e Product page not available — specifications from product listing data\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhat Is Included\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e1x Castair PSH1 pressure switch\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eMounting hardware and electrical connectors not included. Confirm electrical rating and connection type before installing. Always de-energize and depressurize the system before replacing a pressure switch.\u003c\/p\u003e\n\n\u003ch2\u003eWhy Buy From Air Compressor Factory Direct?\u003c\/h2\u003e\n\u003cp\u003ePressure switch selection is more nuanced than just matching the PSI range — you also need to match the electrical rating to the motor and confirm whether your motor and system design require an unloader. We have been working with Cast Air compressor components since 2016 and can help you select the correct switch for your specific unit. Free shipping, free tech support, full manufacturer warranty.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCast Air specialist\u003c\/strong\u003e since 2016\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree shipping\u003c\/strong\u003e on all orders\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFree tech support\u003c\/strong\u003e — we confirm PSH1 vs. PSH1MIX for your application\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eFull manufacturer warranty\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHonest guidance\u003c\/strong\u003e — we tell you if the PSH1MIX is the safer choice\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":53342574706901,"sku":"PSH1","price":66.74,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0622\/8466\/0949\/files\/360_F_473254957_bxG9yf4ly7OBO5I0O5KABlN930GwaMQz.jpg?v=1772652796","url":"https:\/\/aircompressorfactorydirect.com\/products\/castair-pressure-switch-145-175-psi-on-off-no-unloader-psh1","provider":"Air Compressor Factory Direct","version":"1.0","type":"link"}