{"product_id":"dometic-atwood-37021-furnace-limit-switch-8900-ii-8900-iii-series","title":"Dometic \/ Atwood 37021 Furnace Limit Switch – 8900-II \/ 8900-III Series","description":"\u003ch2 data-start=\"139\" data-end=\"215\"\u003eDometic \/ Atwood 37021 Furnace Limit Switch – 8900-II \/ 8900-III Series\u003c\/h2\u003e\n\u003cp data-start=\"216\" data-end=\"243\"\u003e\u003cstrong data-start=\"216\" data-end=\"243\"\u003eGenuine OEM Replacement\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"245\" data-end=\"416\"\u003e\u003cstrong data-start=\"245\" data-end=\"261\"\u003ePart Number:\u003c\/strong\u003e 37021\u003cbr data-start=\"267\" data-end=\"270\"\u003e\u003cstrong data-start=\"270\" data-end=\"287\"\u003eProduct Type:\u003c\/strong\u003e Furnace Limit Switch (High Temperature Safety Switch)\u003cbr data-start=\"341\" data-end=\"344\"\u003e\u003cstrong data-start=\"344\" data-end=\"360\"\u003eApplication:\u003c\/strong\u003e Atwood HydroFlame® 8900-II \u0026amp; 8900-III Series Furnaces\u003c\/p\u003e\n\u003chr data-start=\"418\" data-end=\"421\"\u003e\n\u003ch3 data-start=\"423\" data-end=\"445\"\u003eProduct Overview\u003c\/h3\u003e\n\u003cp data-start=\"447\" data-end=\"627\"\u003eThe \u003cstrong data-start=\"451\" data-end=\"498\"\u003eDometic \/ Atwood 37021 Furnace Limit Switch\u003c\/strong\u003e is a genuine OEM high-temperature safety switch designed for select \u003cstrong data-start=\"567\" data-end=\"626\"\u003eAtwood HydroFlame® 8900-II and 8900-III series furnaces\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp data-start=\"629\" data-end=\"900\"\u003eThis limit switch monitors the internal temperature of the furnace and automatically interrupts burner operation if temperatures exceed safe operating limits. It plays a critical role in preventing overheating and protecting the heat exchanger and surrounding components.\u003c\/p\u003e\n\u003cp data-start=\"902\" data-end=\"1147\"\u003eIf your furnace is shutting down after ignition, short-cycling once warmed up, or failing to maintain burner operation, a weak or failed limit switch may be the cause. Replacing it with OEM Part 37021 restores safe, reliable heating performance.\u003c\/p\u003e\n\u003cp data-start=\"1149\" data-end=\"1263\"\u003eManufactured to original equipment specifications, this component ensures proper fitment and dependable operation.\u003c\/p\u003e\n\u003chr data-start=\"1265\" data-end=\"1268\"\u003e\n\u003ch3 data-start=\"1270\" data-end=\"1288\"\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli data-start=\"1292\" data-end=\"1339\"\u003eGenuine OEM Dometic \/ Atwood replacement part\u003c\/li\u003e\n\u003cli data-start=\"1342\" data-end=\"1380\"\u003eHigh-temperature overheat protection\u003c\/li\u003e\n\u003cli data-start=\"1383\" data-end=\"1427\"\u003eDesigned for 8900-II and 8900-III furnaces\u003c\/li\u003e\n\u003cli data-start=\"1430\" data-end=\"1463\"\u003eRestores safe furnace operation\u003c\/li\u003e\n\u003cli data-start=\"1466\" data-end=\"1524\"\u003eDirect replacement for original factory-installed switch\u003c\/li\u003e\n\u003cli data-start=\"1527\" data-end=\"1573\"\u003eManufactured to original equipment standards\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr data-start=\"1575\" data-end=\"1578\"\u003e\n\u003ch3 data-start=\"1580\" data-end=\"1611\"\u003eCompatible Furnace Models\u003c\/h3\u003e\n\u003cp data-start=\"1613\" data-end=\"1650\"\u003e\u003cstrong data-start=\"1613\" data-end=\"1650\"\u003eAtwood HydroFlame® 8900-II Series\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-start=\"1653\" data-end=\"1665\"\u003e8935-AC-II\u003c\/li\u003e\n\u003cli data-start=\"1668\" data-end=\"1680\"\u003e8935-DC-II\u003c\/li\u003e\n\u003cli data-start=\"1683\" data-end=\"1695\"\u003e8940-AC-II\u003c\/li\u003e\n\u003cli data-start=\"1698\" data-end=\"1710\"\u003e8940-DC-II\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"1712\" data-end=\"1750\"\u003e\u003cstrong data-start=\"1712\" data-end=\"1750\"\u003eAtwood HydroFlame® 8900-III Series\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-start=\"1753\" data-end=\"1766\"\u003e8935-AC-III\u003c\/li\u003e\n\u003cli data-start=\"1769\" data-end=\"1782\"\u003e8935-DC-III\u003c\/li\u003e\n\u003cli data-start=\"1785\" data-end=\"1798\"\u003e8940-AC-III\u003c\/li\u003e\n\u003cli data-start=\"1801\" data-end=\"1814\"\u003e8940-DC-III\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cblockquote data-start=\"1816\" data-end=\"1896\"\u003e\n\u003cp data-start=\"1818\" data-end=\"1896\"\u003eAlways verify your exact furnace model on the unit data plate before ordering.\u003c\/p\u003e\n\u003c\/blockquote\u003e\n\u003chr data-start=\"1898\" data-end=\"1901\"\u003e\n\u003ch3 data-start=\"1903\" data-end=\"1948\"\u003eWhen Should You Replace the Limit Switch?\u003c\/h3\u003e\n\u003cp data-start=\"1950\" data-end=\"2005\"\u003eYou may need to replace the limit switch if you notice:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-start=\"2009\" data-end=\"2048\"\u003eFurnace ignites but shuts off quickly\u003c\/li\u003e\n\u003cli data-start=\"2051\" data-end=\"2075\"\u003eRepeated short cycling\u003c\/li\u003e\n\u003cli data-start=\"2078\" data-end=\"2124\"\u003eBurner operation stops once furnace heats up\u003c\/li\u003e\n\u003cli data-start=\"2127\" data-end=\"2177\"\u003eDiagnostic testing confirms limit switch failure\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"2179\" data-end=\"2280\"\u003eThe limit switch is a critical safety device and should always be replaced with the correct OEM part.\u003c\/p\u003e\n\u003chr data-start=\"2282\" data-end=\"2285\"\u003e\n\u003ch3 data-start=\"2287\" data-end=\"2315\"\u003eProduct Specifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli data-start=\"2319\" data-end=\"2355\"\u003e\n\u003cstrong data-start=\"2319\" data-end=\"2336\"\u003eManufacturer:\u003c\/strong\u003e Dometic \/ Atwood\u003c\/li\u003e\n\u003cli data-start=\"2358\" data-end=\"2382\"\u003e\n\u003cstrong data-start=\"2358\" data-end=\"2374\"\u003ePart Number:\u003c\/strong\u003e 37021\u003c\/li\u003e\n\u003cli data-start=\"2385\" data-end=\"2426\"\u003e\n\u003cstrong data-start=\"2385\" data-end=\"2399\"\u003eComponent:\u003c\/strong\u003e High Limit Safety Switch\u003c\/li\u003e\n\u003cli data-start=\"2429\" data-end=\"2473\"\u003e\n\u003cstrong data-start=\"2429\" data-end=\"2445\"\u003eApplication:\u003c\/strong\u003e 8900-II \u0026amp; 8900-III Series\u003c\/li\u003e\n\u003cli data-start=\"2476\" data-end=\"2509\"\u003e\n\u003cstrong data-start=\"2476\" data-end=\"2489\"\u003eIncludes:\u003c\/strong\u003e Limit switch only\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr data-start=\"2511\" data-end=\"2514\"\u003e\n\u003ch2 data-start=\"2516\" data-end=\"2551\"\u003eFrequently Asked Questions (FAQ)\u003c\/h2\u003e\n\u003ch3 data-start=\"2553\" data-end=\"2598\"\u003eQ: What does a furnace limit switch do?\u003c\/h3\u003e\n\u003cp data-start=\"2599\" data-end=\"2707\"\u003eA: It prevents overheating by shutting off the burner circuit when internal temperatures exceed safe limits.\u003c\/p\u003e\n\u003chr data-start=\"2709\" data-end=\"2712\"\u003e\n\u003ch3 data-start=\"2714\" data-end=\"2753\"\u003eQ: Will this fit 8900-I furnaces?\u003c\/h3\u003e\n\u003cp data-start=\"2754\" data-end=\"2877\"\u003eA: This listing is specifically for 8900-II and 8900-III series models. Always confirm your furnace series before ordering.\u003c\/p\u003e\n\u003chr data-start=\"2879\" data-end=\"2882\"\u003e\n\u003ch3 data-start=\"2884\" data-end=\"2930\"\u003eQ: Is this an OEM Dometic \/ Atwood part?\u003c\/h3\u003e\n\u003cp data-start=\"2931\" data-end=\"2989\"\u003eA: Yes. Part 37021 is a genuine OEM replacement component.\u003c\/p\u003e\n\u003chr data-start=\"2991\" data-end=\"2994\"\u003e\n\u003ch3 data-start=\"2996\" data-end=\"3048\"\u003eQ: Can a bad limit switch cause short cycling?\u003c\/h3\u003e\n\u003cp data-start=\"3049\" data-end=\"3150\"\u003eA: Yes. A weak or failing limit switch can cause the furnace to shut down prematurely after ignition.\u003c\/p\u003e","brand":"RV Furnace Guys","offers":[{"title":"Default Title","offer_id":47854803550449,"sku":null,"price":21.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0784\/4941\/0289\/files\/37021.png?v=1772314431","url":"https:\/\/rvfurnaceguys.com\/products\/dometic-atwood-37021-furnace-limit-switch-8900-ii-8900-iii-series","provider":"RV Furnace Guys","version":"1.0","type":"link"}