{"product_id":"tempstar-40va-transformer-for-t8dnl075b12b2-115v-to-24v-furnace-control-ships-today","title":"Tempstar 40VA Transformer for T8DNL075B12B2 – 115V to 24V Furnace Control | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\n\u003cp\u003eThis is a genuine OEM control transformer (part number 1172810) for the Tempstar T8DNL075B12B2 gas furnace. It steps down incoming 115-volt line power to the 24-volt control voltage that runs your thermostat, gas valve, igniter circuit, and control board. Rated at 40VA, it supplies enough current to drive every low-voltage component on the furnace simultaneously. When a transformer fails, the entire 24V control circuit goes dead: the thermostat screen may go blank, the furnace will not respond to a call for heat, and you may smell a faint burnt odor or see scorched windings on the old unit. A buzzing transformer or one that runs hot to the touch is also on its way out.\u003c\/p\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eSpec\u003c\/th\u003e\n\u003cth\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003ePart Number\u003c\/td\u003e\n\u003ctd\u003e1172810\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003eStep-Down Control Transformer\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eTempstar (ICP \/ Heil)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Voltage\u003c\/td\u003e\n\u003ctd\u003e115V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Voltage\u003c\/td\u003e\n\u003ctd\u003e24V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRating\u003c\/td\u003e\n\u003ctd\u003e40VA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDescription\u003c\/td\u003e\n\u003ctd\u003eTRANS 115\u0026gt;24 40VA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eCompatibility\u003c\/h3\u003e\n\u003cp\u003eEngineered as a direct-fit replacement for the Tempstar T8DNL075B12B2 furnace. The same 1172810 transformer is shared across many ICP-family gas furnaces (Tempstar, Heil, Comfortmaker, Arcoaire) using a 115V primary \/ 24V secondary 40VA control circuit. Confirm your existing transformer is rated 115\/24V 40VA before ordering.\u003c\/p\u003e\n\n\u003ch3\u003eInstallation Guide\u003c\/h3\u003e\n\u003col\u003e\n\u003cli\u003e\n\u003cstrong\u003eSafety First\u003c\/strong\u003e – Disconnect power at the furnace switch and breaker, then verify zero voltage with a multimeter at the transformer leads.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e – Remove the furnace control\/blower compartment service panel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e – Photograph all primary and secondary wire connections before disconnecting anything.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e – Disconnect the line-voltage primary leads and the 24V secondary leads, then unbolt the transformer from its mounting bracket.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e – Mount the new transformer, reconnect primary and secondary leads exactly per your photo, and secure all connections.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e – Restore power and confirm 24V across the secondary, then run a heat cycle to verify normal operation.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eFurnace completely unresponsive to a call for heat with a dead thermostat\u003c\/li\u003e\n\u003cli\u003eNo 24V reading across the secondary leads\u003c\/li\u003e\n\u003cli\u003eVisible scorching, melted windings, or a burnt smell at the transformer\u003c\/li\u003e\n\u003cli\u003eAudible buzzing or the transformer running excessively hot\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eShipping \u0026amp; Returns\u003c\/h3\u003e\n\u003cp\u003eShips same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.\u003c\/p\u003e","brand":"Tempstar","offers":[{"title":"Direct Replacement","offer_id":63021779812723,"sku":"1172810-GEN","price":28.95,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048401912179,"sku":"1172810","price":37.63,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-control-1172810_011a2d01-1066-4ad9-b0e5-ff95e315c898.jpg?v=1782958215","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-40va-transformer-for-t8dnl075b12b2-115v-to-24v-furnace-control-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}