{"product_id":"oem-lennox-contactor-21j03","title":"OEM Lennox Contactor — 21J03","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e21J03\u003c\/strong\u003e contactor is the heavy-duty switch that powers your outdoor unit's compressor and condenser fan motor. When the thermostat calls for cooling, a low-voltage signal energizes the contactor coil, pulling the contacts closed to send line voltage to the compressor. As the primary high-amperage switch in the system, the \u003cstrong\u003e21J03\u003c\/strong\u003e cycles thousands of times per season and must handle significant electrical load reliably.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCommon failure symptoms:\u003c\/strong\u003e A worn \u003cstrong\u003e21J03\u003c\/strong\u003e contactor often shows pitted, burnt, or welded contacts that prevent the compressor from starting or stopping. Watch for a loud humming or buzzing at the outdoor unit, the fan and compressor failing to engage on a cooling call, or the unit that won't shut off because the contacts are stuck closed. Visible arcing, melted housing, or a chattering coil are clear replacement signals.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy OEM matters:\u003c\/strong\u003e Lennox condensing units require a contactor matched to the compressor's amperage draw and the coil's control voltage. The factory \u003cstrong\u003e21J03\u003c\/strong\u003e provides the correct pole configuration, contact rating, and coil spec for a direct fit and safe switching under load. Undersized or mismatched aftermarket contactors overheat and weld shut, risking compressor damage. Choose the OEM part to protect your investment.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081112928627,"sku":"LNX-21J03","price":28.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-contactor-2pole-LNX-21J03.jpg?v=1783759919","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-contactor-21j03","provider":"National HVAC Parts","version":"1.0","type":"link"}