{"product_id":"oem-lennox-defrost-control-board-kit-15d57","title":"OEM Lennox Defrost Control Board Kit — 15D57","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e15D57\u003c\/strong\u003e defrost control board kit manages the defrost cycle on your Lennox heat pump, monitoring outdoor coil temperature and timing to clear frost buildup during cold-weather operation. It coordinates the reversing valve, outdoor fan, and auxiliary heat so your system sheds ice efficiently and returns to normal heating without wasting energy.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCommon failure symptoms:\u003c\/strong\u003e The \u003cstrong\u003e15D57\u003c\/strong\u003e often fails when you notice the outdoor unit icing over and never clearing, a heat pump that runs continuously in defrost, cold air blowing indoors, tripped breakers, or the outdoor fan behaving erratically. Cracked solder joints, corroded terminals, and heat-stressed relays are typical causes of board failure.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy OEM matters:\u003c\/strong\u003e Lennox control boards are engineered to exact voltage, timing, and relay specifications for their heat pump platforms. Installing the factory \u003cstrong\u003e15D57\u003c\/strong\u003e ensures correct defrost logic, proper sensor compatibility, and reliable communication with the rest of your system — protecting the compressor and preserving rated efficiency. Aftermarket substitutes can mistime cycles and shorten component life. Always confirm the part number matches your unit's rating plate before installing.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081145139571,"sku":"LNX-15D57","price":129.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-control-board-defrost-LNX-15D57.jpg?v=1783760046","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-defrost-control-board-kit-15d57","provider":"National HVAC Parts","version":"1.0","type":"link"}