{"product_id":"18557-1-aerco-boiler-and-water-heater-pneumatic-bulb-tstat-ra-20-240","title":"18557-1  AERCO Boiler and Water Heater Pneumatic Bulb TSTAT RA-20\/240","description":"\u003ch2\u003e18557-1 AERCO Boiler and Water Heater Pneumatic Bulb TSTAT RA-20\/240\u003c\/h2\u003e\n\u003cp\u003e\u003cb\u003e\u003cspan style=\"font-size: large;\"\u003e\u003cspan style=\"background-color: rgb(255, 255, 0);\"\u003eNormal Stocking Item in Our Warehouse\u003c\/span\u003e \u003c\/span\u003e\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eAERCO 18557‑1 is the OEM Pneumatic Bulb Thermostat (RA‑20\/240)\u003c\/strong\u003e used on AERCO boilers and water heaters. Grounded documentation and distributor listings confirm its identity, specifications, and application.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eAERCO 18557‑1 Pneumatic Bulb Thermostat (RA‑20\/240) — OEM reverse‑acting pneumatic temperature controller for AERCO boilers and water heaters. Features a remote liquid‑filled sensing bulb for accurate hydronic temperature regulation and stable pneumatic control. Required for heat exchangers equipped with anticipator temperature‑control systems.\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003ch2\u003e🔧 Core Identity \u0026amp; Function\u003c\/h2\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003ePart Number:\u003c\/strong\u003e 18557‑1 \u003cstrong\u003eComponent:\u003c\/strong\u003e Pneumatic Bulb Thermostat \u003cstrong\u003eSeries:\u003c\/strong\u003e RA‑20\/240 \u003cstrong\u003eOEM:\u003c\/strong\u003e AERCO\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis thermostat is a \u003cstrong\u003ereverse‑acting pneumatic temperature controller\u003c\/strong\u003e. As temperature rises, its \u003cstrong\u003eoutput air pressure decreases\u003c\/strong\u003e, and vice‑versa. It uses a \u003cstrong\u003eremote, liquid‑filled sensing bulb\u003c\/strong\u003e designed specifically for AERCO heat exchangers.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eIt is used when the heat exchanger \u003cstrong\u003eincludes an anticipator temperature‑control system\u003c\/strong\u003e. \u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv class=\"relative pb-6 w-full after:border-b after:border-stroke-300 after:w-full after:absolute after:mt-3\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003ch2\u003e📐 Technical Specifications (Grounded)\u003c\/h2\u003e\n\u003cp\u003e\u003cspan\u003eFrom AERCO Instruction AC‑103:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul role=\"list\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eTemperature range:\u003c\/strong\u003e −20°F to +240°F\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eMax bulb temperature:\u003c\/strong\u003e 310°F\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eMax controller case temperature:\u003c\/strong\u003e 150°F ambient\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eAir supply:\u003c\/strong\u003e 20–30 PSIG\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eAir consumption:\u003c\/strong\u003e 0.008 SCFM\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eAir capacity:\u003c\/strong\u003e Up to 16 SCFM for mains sizing\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eAction:\u003c\/strong\u003e Reverse‑acting pneumatic control\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eSensor:\u003c\/strong\u003e Remote averaging liquid‑filled bulb\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eApplications\u003c\/h2\u003e\n\u003cp\u003e\u003cspan\u003eUsed in:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul role=\"list\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eAERCO boilers and water heaters\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003ePneumatic building‑automation loops\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eHydronic heating plants\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eIndustrial HVAC temperature‑regulation systems\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eImportant installation note:\u003c\/strong\u003e 18557‑1 must be used \u003cstrong\u003eonly\u003c\/strong\u003e on AERCO heat exchangers equipped with an \u003cstrong\u003eanticipator system\u003c\/strong\u003e. \u003c\/span\u003e\u003c\/p\u003e","brand":"Neuco","offers":[{"title":"Default Title","offer_id":45558655418434,"sku":"18557-1","price":4911.4,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1071\/8320\/files\/Pic_large_986576e4-79bc-41f4-b78d-30ed0e8d3b46.webp?v=1739516663","url":"https:\/\/hvacpartstore.com\/products\/18557-1-aerco-boiler-and-water-heater-pneumatic-bulb-tstat-ra-20-240","provider":"HVACpartstore","version":"1.0","type":"link"}