{"product_id":"tempstar-40va-transformer-for-t8mpl075b12b2-115v-to-24v-ships-today","title":"Tempstar 40VA Transformer for T8MPL075B12B2 | 115V to 24V | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis genuine OEM 40VA control transformer (part number 1172810) steps 115V line voltage down to the 24V control voltage that runs the thermostat, gas valve, igniter circuit, and control board on the Tempstar T8MPL075B12B2 furnace. The transformer is the heart of the low-voltage control system - when it fails, the furnace goes completely dead: no thermostat response, no call for heat, and no 24V at the control board. Failures are typically caused by a shorted control wire, a stuck gas valve drawing excess current, or simple age and heat fatigue. This factory-correct 40VA unit provides ample capacity for the furnace's control load.\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 (ICP)\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\u003eFitment\u003c\/td\u003e\n\u003ctd\u003eOEM exact replacement\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cp\u003eFits the Tempstar T8MPL075B12B2 gas furnace and related ICP-built furnaces under the Tempstar, Heil, and Comfortmaker brands that use the 115V-to-24V 40VA control transformer. Verify your existing transformer is rated 40VA with a 115V primary 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 with a multimeter before working.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e - Remove the control\/blower service panel to reach the transformer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e - Photograph all primary and secondary wire connections before disconnecting them.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e - Disconnect the leads, remove the mounting screws, and lift out the failed transformer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e - Mount the new transformer, reconnect the 115V primary and 24V secondary leads exactly per your photo.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e - Restore power, confirm 24V at the secondary, and verify the furnace responds to a thermostat call for heat.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eFurnace completely unresponsive with no thermostat display or call\u003c\/li\u003e\n\u003cli\u003eNo 24V measured at the control board or secondary terminals\u003c\/li\u003e\n\u003cli\u003eBurnt smell or visibly scorched transformer windings\u003c\/li\u003e\n\u003cli\u003eRepeated blown low-voltage fuse traced to a failed transformer\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":63021777355123,"sku":"1172810-GEN","price":28.95,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048402862451,"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_e33a8ded-e248-4deb-b0e6-55eb45f8bc53.jpg?v=1782958249","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-40va-transformer-for-t8mpl075b12b2-115v-to-24v-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}