{"product_id":"tempstar-40va-transformer-for-t8mpn050b12a1-115v-to-24v-control-transformer-ships-today","title":"Tempstar 40VA Transformer for T8MPN050B12A1 — 115V to 24V Control Transformer | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\n\u003cp\u003eThis genuine OEM control transformer (part number 1012722, TRANS 115\u0026gt;24 40VA) steps the 115V line voltage down to the 24V control voltage that powers the thermostat, gas valve, relays, and control board on the Tempstar T8MPN050B12A1 furnace. Rated at 40VA, it provides ample capacity for the furnace's low-voltage control circuit. When a transformer fails — often from a shorted thermostat wire or a stuck contactor drawing excess current — the entire 24V system goes dead: no thermostat display, no blower, no ignition. A failed transformer frequently takes out an inline fuse on the control board, so inspect and replace that fuse as well. Installing the correct 40VA OEM transformer restores reliable control power.\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\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\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\u003eFits Model\u003c\/td\u003e\n\u003ctd\u003eT8MPN050B12A1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFitment\u003c\/td\u003e\n\u003ctd\u003eGenuine OEM\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eCompatibility\u003c\/h3\u003e\n\u003cp\u003eFactory control transformer for the Tempstar T8MPN050B12A1 gas furnace. As a common ICP-built component, part 1012722 services a wide range of ICP, Heil, and Comfortmaker furnaces and air handlers using a 115V-to-24V 40VA control circuit. Confirm voltage and VA against your unit before ordering.\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 switch and breaker and verify zero voltage with a multimeter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the furnace control\/service panel.\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 leads, remove the mounting screws or nut, and lift out the failed transformer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Mount the new 40VA transformer, reconnect the 115V primary and 24V secondary leads exactly per your photo, and check the control-board fuse.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power, confirm 24V at the secondary with a meter, and 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\u003eNo 24V control power — dead thermostat and no system response\u003c\/li\u003e\n\u003cli\u003eRepeatedly blown 3-amp control-board fuse\u003c\/li\u003e\n\u003cli\u003eBurnt smell or visibly scorched\/melted transformer housing\u003c\/li\u003e\n\u003cli\u003eMeasured secondary voltage well below 24V under load\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":63021776273779,"sku":"1012722-GEN","price":26.95,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048403681651,"sku":"1012722","price":35.04,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-control-1012722_06150ab2-d066-47de-be0b-c9ba5c676343.jpg?v=1782958280","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-40va-transformer-for-t8mpn050b12a1-115v-to-24v-control-transformer-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}