{"product_id":"tempstar-40va-transformer-for-t8dnl050b12b1-115v-to-24v-ships-today","title":"Tempstar 40VA Transformer for T8DNL050B12B1 — 115V to 24V | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis OEM control transformer supplies the 24V low-voltage power for the Tempstar T8DNL050B12B1 gas furnace. It steps incoming 115V line voltage down to 24V to run the thermostat, control board, gas valve, and relays. Rated at 40VA, it provides the standard control-circuit capacity for residential furnaces. When the transformer fails, the entire low-voltage system goes dead: no thermostat display, no call for heat, and no response from the control board even though line power is present. This listing covers OEM part 1172810 (TRANS 115\u0026gt;24 40VA). A blown transformer is frequently the result of a shorted thermostat wire or a failed downstream component, so inspect the low-voltage wiring before installing the replacement.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\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\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRating\u003c\/td\u003e\n\u003ctd\u003e40 VA\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\u003eFit\u003c\/td\u003e\n\u003ctd\u003eOEM Direct Replacement\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cp\u003eBuilt for the Tempstar T8DNL050B12B1 and other ICP\/Heil\/Comfortmaker furnaces using a 40VA 115V-to-24V control transformer. Match VA rating and voltage to your original before installing.\u003c\/p\u003e\u003ch3\u003eInstallation Guide\u003c\/h3\u003e\u003col\u003e\n\u003cli\u003e\n\u003cstrong\u003eSafety First\u003c\/strong\u003e — Disconnect power at the furnace switch and breaker. Verify zero voltage with a multimeter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the control compartment service panel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph the primary (line) and secondary (24V) wiring before disconnecting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Disconnect the leads and unbolt the old transformer from its bracket.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Mount the new transformer, then reconnect primary and secondary leads exactly per your photo.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power and confirm 24V at the secondary and a working thermostat call for heat.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eBlank thermostat with line power present\u003c\/li\u003e\n\u003cli\u003eNo 24V at the control board secondary terminals\u003c\/li\u003e\n\u003cli\u003eFurnace will not respond to any call for heat\u003c\/li\u003e\n\u003cli\u003eBurned smell or visible scorching on the transformer\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eShipping \u0026amp; Returns\u003c\/h3\u003e\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":63021780861299,"sku":"1172810-GEN","price":24.0,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048401650035,"sku":"1172810","price":31.2,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-control-1172810_7acbfb8a-eaf8-4ced-9b93-2a6688b54768.jpg?v=1782958205","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-40va-transformer-for-t8dnl050b12b1-115v-to-24v-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}