{"product_id":"resideo-pa404b1023-u-pressuretrol-controller-steam","title":"Resideo pa404b1023\/u Pressuretrol Controller Steam","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe RESIDEO pa404b1023\/u is a pressure-actuated controller designed for steam heating systems. This model makes the fan circuit when a rise in steam pressure confirms the presence of steam, enabling proper fan operation in suspension-type unit heater applications. At its core, a sensitive diaphragm expands and contracts in response to pressure changes, moving a lever mechanism that operates an SPST MICRO SWITCH snap-acting switch. Set point adjustment is accessible via a screw on top of the case without removing the cover, and the differential is set using a dial located inside the case. Licensed HVAC and steam heating technicians are the typical installers for this control.\u003c\/p\u003e\n\u003cp\u003eThe pa404b1023\/u is intended for use with suspension-type unit heaters in steam heating systems. When steam pressure rises to the set point, the controller closes the fan circuit, signaling that steam is present and the unit heater fan should operate. This makes it well suited for commercial and industrial spaces where suspended unit heaters deliver radiant or forced convection heat from a centralized steam boiler. It is not a high-limit safety control; it functions as a make-on-rise pressure switch in the fan circuit.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003ePressure-actuated diaphragm responds to steam pressure variations for reliable switching\u003c\/li\u003e\n  \u003cli\u003eSPST MICRO SWITCH snap-acting switch provides positive, low-bounce circuit make and break\u003c\/li\u003e\n  \u003cli\u003eSet point adjustment via external screw without removing the controller cover\u003c\/li\u003e\n  \u003cli\u003eDifferential adjustment via internal dial for fine-tuned pressure control\u003c\/li\u003e\n  \u003cli\u003eMakes fan circuit on pressure rise, confirming steam presence in suspension-type unit heaters\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned for use with suspension-type unit heaters in steam heating systems where a make-on-rise pressure control is required in the fan circuit.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eInstallation should be performed by a licensed HVAC or steam heating technician familiar with low-pressure steam systems. Shut down the boiler and relieve all system pressure before connecting or disconnecting the controller. Ensure wiring to the fan circuit complies with applicable NEC requirements for the voltage and load involved. Verify the set point and differential settings match the system design before returning the boiler to service.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSwitch Type\u003c\/strong\u003e: SPST MICRO SWITCH snap-acting\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eActuator Type\u003c\/strong\u003e: Pressure-actuated diaphragm\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAction\u003c\/strong\u003e: Make on pressure rise (fan circuit)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSet Point Adjustment\u003c\/strong\u003e: External screw, cover-on access\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDifferential Adjustment\u003c\/strong\u003e: Internal dial\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eStandard Information\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: RESIDEO\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: pa404b1023\/u\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"RESIDEO","offers":[{"title":"Default Title","offer_id":51467683496242,"sku":"PA404B1023\/U","price":336.24,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/PA404B1023-U.jpg?v=1783910242","url":"https:\/\/voomisupply.com\/products\/resideo-pa404b1023-u-pressuretrol-controller-steam","provider":"Voomi Supply","version":"1.0","type":"link"}