{"product_id":"tempstar-40va-transformer-for-t9mpv050f12a3-115v-to-24v-ships-today","title":"Tempstar 40VA Transformer for T9MPV050F12A3 — 115V to 24V | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\n\u003cp\u003eThis is a genuine OEM control transformer (part number 1012722) for the Tempstar T9MPV050F12A3 variable-speed gas furnace. It steps the 115V line voltage down to the 24V secondary that powers the furnace control board, gas valve, thermostat circuit, and relays. Rated at 40VA, it supplies enough capacity to drive the low-voltage controls plus a typical accessory load. When a transformer fails, the entire 24V control system goes dead: no thermostat display, no blower or ignition response, and no heating or cooling. Failures are usually caused by a shorted secondary, an overloaded circuit, or a power surge, and an open thermal fuse inside the windings is a common end-of-life symptom.\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\u003e1012722\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDescription\u003c\/td\u003e\n\u003ctd\u003eTransformer (TRANS 115\u0026gt;24 40VA)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003eControl \/ Step-Down\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 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\u003eDirect OEM replacement for the Tempstar T9MPV050F12A3 variable-speed gas furnace and shared across ICP-family equipment (Tempstar, Heil, Comfortmaker, and related Carrier\/ICP platforms). Confirm the 115V primary \/ 24V secondary, 40VA rating, and part number 1012722 against your existing transformer 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; verify zero voltage with a multimeter before handling wiring.\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 every primary and secondary lead and terminal before disconnecting.\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 the 115V primary and 24V secondary leads exactly per your photos, and secure all connections.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power and confirm 24V at the secondary with a multimeter, then verify the thermostat, blower, and ignition respond normally.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eDead thermostat display and no 24V control power\u003c\/li\u003e\n\u003cli\u003eFurnace completely unresponsive to heating or cooling calls\u003c\/li\u003e\n\u003cli\u003eNo measurable 24V at the secondary terminals under load\u003c\/li\u003e\n\u003cli\u003eRepeated blown control fuses or a burnt-smelling transformer\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":63021680099699,"sku":"1012722-GEN","price":29.0,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048407122291,"sku":"1012722","price":37.7,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-control-1012722_537444f2-3700-42da-976c-9f76de983e1d.jpg?v=1782958397","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-40va-transformer-for-t9mpv050f12a3-115v-to-24v-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}