{"product_id":"23484-suburban-limit-sw-l77-nt20sq-yellow","title":"233484 Suburban LIMIT SW – L77 – NT20SQ – (YELLOW)","description":"\u003ch1 class=\"product_title entry-title\"\u003e\u003cstrong\u003e233484 Suburban LIMIT SW – L77 – NT20SQ – (YELLOW)\u003c\/strong\u003e\u003c\/h1\u003e\n\u003cp\u003e\u003cspan\u003eThe \u003cstrong\u003e233484 Suburban Limit Switch – L77 – NT20SQ (Yellow)\u003c\/strong\u003e \u003cstrong\u003eNT-12 16 20S\u003c\/strong\u003e is the OEM auto‑reset high‑limit switch used in Suburban \u003cstrong\u003eNT20SQ\u003c\/strong\u003e furnaces. It protects the furnace from overheating by opening the circuit when the heat exchanger reaches its rated temperature limit. Once temperatures drop back into the safe range, the switch automatically resets and allows the furnace to resume normal operation. Your product page confirms the part number, color, and compatibility, along with the list of OEM replacement numbers.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch2\u003e\u003cspan\u003e\u003cstrong\u003eReplaces: \u003c\/strong\u003eA31023, 230621, 230635, 233020, 233021, 233022\u003c\/span\u003e\u003c\/h2\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\u003ch3\u003eFunction and Role in the Furnace\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003eThis limit switch is part of the furnace’s safety chain. It:\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eMonitors heat exchanger temperature\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eOpens the circuit if temperatures exceed the \u003cstrong\u003eL77°F\u003c\/strong\u003e limit rating\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eAutomatically resets when temperatures fall\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003ePrevents overheating, short‑cycling, and heat‑exchanger damage\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eWorks with the sail switch, ignition board, and thermostat to maintain safe operation\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eA failing limit switch often causes intermittent heating, furnace shutdowns, or blower‑only operation.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eOEM Suburban \u003cstrong\u003eauto‑reset limit switch\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eTemperature rating: \u003cstrong\u003eL77\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eDesigned for \u003cstrong\u003eNT20SQ\u003c\/strong\u003e furnaces\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eYellow identification for correct model matching\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eDirect‑fit replacement with OEM wiring and mounting\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eRestores proper furnace safety and cycling behavior\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"Laurelhurst","offers":[{"title":"Default Title","offer_id":42464827867202,"sku":"S233484","price":3.47,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1071\/8320\/files\/Screenshot2025-09-21185613.png?v=1758506202","url":"https:\/\/hvacpartstore.com\/products\/23484-suburban-limit-sw-l77-nt20sq-yellow","provider":"HVACpartstore","version":"1.0","type":"link"}