{"product_id":"factory-authorized-parts™-hh18ha508-switch-limit-ls1-120-160-f-auto-reset","title":"Factory Authorized Parts™ HH18HA508 SWITCH LIMIT (LS1) 120-160°F Auto Reset","description":"\u003ch1\u003eFactory Authorized Parts™ HH18HA508 SWITCH LIMIT (LS1) 120-160°F Auto Reset\u003c\/h1\u003e\n\u003ch2\u003eThe Intelligent Thermal Regulator\u003c\/h2\u003e\n\u003cp\u003eThe \u003cstrong\u003eHH18HA508\u003c\/strong\u003e is a critical \"LS1\" primary limit switch engineered to serve as the thermal safety brain for high-performance gas furnaces. Designed specifically for \u003cstrong\u003eCarrier, Bryant, and Payne equipment\u003c\/strong\u003e, this automatic reset switch monitors the temperature of the air passing over the heat exchanger. Its primary function is to prevent system overheating by interrupting the heating cycle if temperatures exceed safe operating parameters. By ensuring the furnace stays within its engineered 120°F to 160°F window, it preserves the integrity of the heat exchanger and maintains the peak efficiency of your HVAC system. \u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExact OEM Part Number:\u003c\/strong\u003e A genuine \u003cstrong\u003eHH18HA508\u003c\/strong\u003e Factory Authorized Part, ensuring 100% mechanical and electrical compatibility with your specific furnace cabinet.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAutomatic Reset Logic:\u003c\/strong\u003e Unlike rollout switches, this \"LS1\" limit features an \u003cstrong\u003eauto-reset\u003c\/strong\u003e function that restores furnace operation once internal temperatures cool to the safe \"cut-in\" threshold.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDual-Point Thermal Control:\u003c\/strong\u003e Precision-calibrated to \u003cstrong\u003eopen at 160°F\u003c\/strong\u003e (interrupting heat) and \u003cstrong\u003eclose at 120°F\u003c\/strong\u003e (resuming operation), providing a reliable safety buffer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIntegrated Safety Monitoring:\u003c\/strong\u003e Continuously communicates with the furnace control board to prevent heat-related damage and ensure the system shuts down safely if airflow is restricted.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eQuick-Connect Installation:\u003c\/strong\u003e Features standard spade terminals for a fast, secure connection to the existing safety circuit, resolving nuisance tripping caused by aging, \"weak\" switches. \u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Factory Authorized Parts™ (Carrier\/Bryant\/Payne)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Carrier Corporation\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e HH18HA508\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.02 lbs\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVoltage:\u003c\/strong\u003e 120V \/ 24V (Pilot Duty)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAmperage:\u003c\/strong\u003e 0.84 amp\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReset Type:\u003c\/strong\u003e Automatic Reset\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTemperature Range:\u003c\/strong\u003e 120°F Cut-In \/ 160°F Cut-Out\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e 1\" Depth x 4\" Height x 9\" Width (Package size) \u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003e🛠️ HVAC Depot Pro Tip\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003e\"Check the Filter Before Replacing!\"\u003c\/strong\u003e If your furnace is short-cycling and you suspect the HH18HA508 has failed, first check for restricted airflow. A dirty air filter, blocked return vents, or a dusty evaporator coil are the most common reasons this switch trips. Before installing the new part, \u003cstrong\u003etake a picture\u003c\/strong\u003e of the mounting orientation; ensure the bi-metal sensing element is fully inserted into the airflow stream for accurate temperature detection.\u003c\/p\u003e\n\u003ch2\u003eCross-Reference\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSuperseded \/ Legacy Numbers:\u003c\/strong\u003e HH18HA508A\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Codes:\u003c\/strong\u003e 1NT01L-4577, 4349808\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC\/Drawing Numbers:\u003c\/strong\u003e 00662442666758, L\/1 \u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eModel Compatibility\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003e58STA\/STX Series\u003c\/strong\u003e (Suffixes: 070-14116, 070-16108, 070-16112, 070-12116, 070-13116)\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e58SB\/SC Series\u003c\/strong\u003e (Suffixes: 0A090E211116, 0A070E171212, 0A090E211116, 0B090M171114, 1A070E171116)\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e58PHB\/PHA Series\u003c\/strong\u003e (Suffixes: 070-10116, 070-10112, 090-10114, 090-10116, 110-10120, 110-12120)\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePG8M\/PG80 Series\u003c\/strong\u003e (Suffixes: EA048070AAJA, JAA048070ACJA, ESAA48090CBA, ESAA42090BBA, MAA048070ADJA)\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e801SA\/811SA Series\u003c\/strong\u003e (Suffixes: 36070E17A-A, 42090E17A-C, 48090E21A-C, 60155E24A-A)\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"Carrier","offers":[{"title":"Default Title","offer_id":52235450351979,"sku":"662442666758","price":35.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0922\/9683\/9531\/files\/HH18HA416.jpg?v=1772040855","url":"https:\/\/tophvacparts.com\/products\/factory-authorized-parts%e2%84%a2-hh18ha508-switch-limit-ls1-120-160-f-auto-reset","provider":"HVAC Parts and Equipment Depot Open To Homeowners and Contractors","version":"1.0","type":"link"}