{"product_id":"tempstar-40va-transformer-for-t9mpv075f12b1-115v-to-24v-control-ships-today","title":"Tempstar 40VA Transformer for T9MPV075F12B1 — 115V to 24V Control | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\n\u003cp\u003eThis is the OEM control transformer (Part Number 1012722) for the Tempstar T9MPV075F12B1 gas furnace. It steps the 115-volt incoming line voltage down to the 24-volt control circuit that powers the thermostat, ignition control board, gas valve, and relays. Rated at 40VA, it supplies the current needed for the full control sequence on this variable-speed furnace. A failed transformer kills the entire low-voltage side — no thermostat display, no call for heat, and no ignition. The usual culprit is a shorted secondary winding caused by an overloaded or pinched control wire, which often blows the board's low-voltage fuse as soon as power returns. Replacing it with the correct OEM 40VA transformer restores reliable 24V control power and protects the ignition board.\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\u003eType\u003c\/td\u003e\n\u003ctd\u003eControl 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\u003eFits Model\u003c\/td\u003e\n\u003ctd\u003eT9MPV075F12B1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eCompatibility\u003c\/h3\u003e\n\u003cp\u003eBuilt for the Tempstar T9MPV075F12B1 furnace and shared across the ICP\/Heil\/Comfortmaker family of 9-series variable-speed gas furnaces that use the 1012722 transformer. Verify your existing unit is a 115V-to-24V, 40VA 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 at the transformer primary leads with a multimeter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the furnace control\/blower compartment door.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph all primary (line) and secondary (24V) wire connections before disconnecting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Disconnect the line-voltage and 24V secondary leads, then unbolt the transformer from its bracket.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Mount the new transformer, reconnect primary and secondary leads exactly per your photo, and tighten all terminals.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power, confirm 24V across the secondary, and run a full heat cycle to verify ignition and blower operation.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eNo power to the thermostat or control board (dead 24V circuit).\u003c\/li\u003e\n\u003cli\u003eRepeatedly blown low-voltage fuse on the ignition control board.\u003c\/li\u003e\n\u003cli\u003eNo measurable voltage across the transformer secondary with line power present.\u003c\/li\u003e\n\u003cli\u003eBurnt smell or visible scorching on the transformer housing.\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":63021679509875,"sku":"1012722-GEN","price":24.95,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048407417203,"sku":"1012722","price":32.44,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-control-1012722_b5725143-3c86-4fdb-89a0-6fc817e648e5.jpg?v=1782958409","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-40va-transformer-for-t9mpv075f12b1-115v-to-24v-control-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}