{"product_id":"tempstar-40va-transformer-for-t8mpl125j20b2-115v-to-24v-class-ii-ships-today","title":"Tempstar 40VA Transformer for T8MPL125J20B2 — 115V to 24V Class II | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis OEM control transformer (part #1172810) steps 115-volt line power down to the 24-volt control voltage that your Tempstar T8MPL125J20B2 furnace uses to operate its thermostat, gas valve, igniter, and control board. Rated at 40VA, it supplies enough capacity to drive the full low-voltage control circuit. When a transformer fails, the entire 24V control system goes dead: the thermostat screen may go blank, the furnace won't respond to a heat call, and you may smell a faint burnt-electrical odor or find a blown low-voltage fuse on the control board. A buzzing or overheating transformer is also a sign the windings are breaking down.\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 (Class II)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eTempstar (ICP \/ Heil \/ Comfortmaker)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrimary Voltage\u003c\/td\u003e\n\u003ctd\u003e115 VAC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSecondary Voltage\u003c\/td\u003e\n\u003ctd\u003e24 VAC\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\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cp\u003eDirect OEM fit for the Tempstar T8MPL125J20B2 gas furnace and other ICP-family models (Heil, Comfortmaker, Arcoaire, Keeprite) that specify part 1172810. Always confirm your existing transformer's VA rating and voltage match before ordering.\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, then verify zero voltage at the transformer leads with a multimeter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the furnace control\/blower access panel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph all primary (line) and secondary (24V) wire connections before disconnecting anything.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Disconnect the primary and 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 the line and 24V leads exactly per your photo, and confirm the ground.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power and verify 24 VAC across the secondary terminals and normal furnace start-up.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eBlank thermostat or no response to a heat call\u003c\/li\u003e\n\u003cli\u003eRepeatedly blown 3A or 5A low-voltage control-board fuse\u003c\/li\u003e\n\u003cli\u003eAudible buzzing or hot\/burnt smell from the transformer\u003c\/li\u003e\n\u003cli\u003eNo measurable 24 VAC on the secondary side\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eShipping \u0026amp; Returns\u003c\/h3\u003e\u003cp\u003eShips same day on orders placed 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":63021776372083,"sku":"1172810-GEN","price":28.95,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048403583347,"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_072294c3-11ee-40ca-ba3c-d0e9e0845c3a.jpg?v=1782958278","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-40va-transformer-for-t8mpl125j20b2-115v-to-24v-class-ii-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}