{"product_id":"tempstar-40va-transformer-for-t9mpv125l20a3-115v-to-24v-ships-today","title":"Tempstar 40VA Transformer for T9MPV125L20A3 — 115V to 24V | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis is the genuine OEM 40VA control transformer (part number 1012722) for the Tempstar T9MPV125L20A3 gas furnace. The transformer steps line voltage (115V) down to the 24V low-voltage control circuit that powers the thermostat, control board, gas valve, and ignition system. A 40VA rating provides ample capacity for the furnace's full control load. When a transformer fails, the entire low-voltage circuit goes dead — the furnace will not respond to a thermostat call, the control board may show no power, and you may notice a burnt smell or a tripped\/blown low-voltage fuse caused by a short on the 24V side.\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\u003e1012722\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDescription\u003c\/td\u003e\n\u003ctd\u003eTRANS 115\u0026gt;24 40VA\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\u003e40 VA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFitment\u003c\/td\u003e\n\u003ctd\u003eOEM Replacement\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cp\u003eEngineered as a direct OEM replacement for the Tempstar T9MPV125L20A3 modulating gas furnace. The 1012722 transformer is shared across many ICP-family models (Tempstar, Heil, Comfortmaker, Arcoaire) using the same 115V-to-24V 40VA control platform. Always confirm your existing transformer's part number or VA rating 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.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the furnace control\/blower access 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 line-voltage primary leads and the 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, reconnect primary and secondary wiring exactly per your photo, and secure all connections.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power and confirm 24V across the secondary terminals and normal furnace operation.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eNo 24V power — furnace does not respond to thermostat calls.\u003c\/li\u003e\n\u003cli\u003eRepeatedly blown or tripped low-voltage fuse.\u003c\/li\u003e\n\u003cli\u003eBuzzing, overheating, or a burnt smell from the transformer.\u003c\/li\u003e\n\u003cli\u003eMeasured secondary voltage is zero or well below 24V.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eShipping \u0026amp; Returns\u003c\/h3\u003e\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":63021678526835,"sku":"1012722-GEN","price":28.0,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048407875955,"sku":"1012722","price":36.4,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-control-1012722_3db61480-1fad-475d-8744-2b214d45d146.jpg?v=1782958428","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-40va-transformer-for-t9mpv125l20a3-115v-to-24v-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}