{"product_id":"tempstar-40va-transformer-for-t9mpx080j16a2-115v-to-24v-step-down-ships-today","title":"Tempstar 40VA Transformer for T9MPX080J16A2 — 115V to 24V Step-Down | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\n\u003cp\u003eThis OEM control transformer (part number 1172810) steps 115V line voltage down to the 24V low-voltage power your Tempstar T9MPX080J16A2 furnace needs to operate its control board, thermostat circuit, gas valve, and ignition system. Rated at 40VA, it delivers steady, regulated power to every 24V component. When the transformer fails, the whole control circuit loses power: the thermostat goes dark, the furnace ignores calls for heat, and the board shows no low-voltage supply. Buzzing, a burnt smell in the control compartment, or repeatedly blown low-voltage fuses point to a failed or overloaded transformer. A genuine OEM 40VA replacement restores correct voltage and protects the rest of the control circuit.\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\u003eFit\u003c\/td\u003e\n\u003ctd\u003eOEM Direct Replacement\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 OEM fit for the Tempstar T9MPX080J16A2 gas furnace. The 1172810 transformer is shared across many ICP-family furnaces sold under the Tempstar, Heil, and Comfortmaker brands. Verify your existing transformer is a 115V-to-24V 40VA unit before installing.\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.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the furnace control\/blower service panel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph all primary and secondary wire connections before disconnecting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Disconnect the 115V primary and 24V secondary leads, then unbolt the failed transformer from its mounting bracket.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Mount the new transformer and 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 across the secondary and a normal call for heat.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eBlank thermostat and no 24V power at the control board.\u003c\/li\u003e\n\u003cli\u003eFurnace does not respond to a call for heat.\u003c\/li\u003e\n\u003cli\u003eAudible buzzing or burnt smell from the control compartment.\u003c\/li\u003e\n\u003cli\u003eRepeated blown low-voltage fuses or no secondary output on a multimeter.\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":63021678035315,"sku":"1172810-GEN","price":24.95,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048408236403,"sku":"1172810","price":32.44,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-control-1172810_e12a23c7-29f9-4350-a8e5-6ac268d40236.jpg?v=1782958441","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-40va-transformer-for-t9mpx080j16a2-115v-to-24v-step-down-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}