{"product_id":"oem-lennox-fan-and-limit-control-11m40","title":"OEM Lennox Fan and Limit Control — 11M40","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e11M40\u003c\/strong\u003e fan and limit control is a dual-function device that manages both blower operation and overheat protection in your Lennox furnace. It senses plenum temperature to energize the blower once the heat exchanger is warm and de-energize it after the burners shut off, while its integrated high-limit function cuts the burners if temperatures ever exceed the safe threshold.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCommon failure symptoms:\u003c\/strong\u003e When the \u003cstrong\u003e11M40\u003c\/strong\u003e fails, you may notice the blower running constantly or not starting at all, cold air blowing at the start of a heat cycle, furnace short-cycling, or safety lockouts on overheat. A control that is out of calibration disrupts proper fan timing and comfort.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy OEM matters:\u003c\/strong\u003e Because the \u003cstrong\u003e11M40\u003c\/strong\u003e combines blower timing and critical safety limits in one calibrated unit, using the genuine Lennox part is essential. Aftermarket controls may not match the correct fan-on\/fan-off setpoints or limit trip temperature, risking poor performance or compromised safety. The OEM part guarantees exact fit and factory-rated operation.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081115877747,"sku":"LNX-11M40","price":19.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-limit-switch-snap-disc-LNX-11M40.jpg?v=1783760738","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-fan-and-limit-control-11m40","provider":"National HVAC Parts","version":"1.0","type":"link"}