{"product_id":"tempstar-40va-transformer-for-t8mpn100f20a1-furnace-115v-to-24v-ships-today","title":"Tempstar 40VA Transformer for T8MPN100F20A1 Furnace — 115V to 24V | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis OEM control transformer (part number 1012722, \"TRANS 115\u0026gt;24 40VA X\") supplies the 24-volt control power for the Tempstar T8MPN100F20A1 gas furnace. It steps line voltage of 115V down to a 24V secondary and is rated at 40VA, enough to drive the control board, thermostat, gas valve, and ignition circuit. When the transformer fails, the entire low-voltage control system goes dead: no thermostat display, no call for heat, and the furnace will not respond. Transformers commonly fail from a shorted secondary (often caused by a pinched or grounded thermostat wire) or from an overloaded control circuit. Replacing it restores 24V power to the furnace controls.\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\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\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\u003eT8MPN100F20A1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cp\u003eDesigned for the Tempstar T8MPN100F20A1 furnace and interchangeable across ICP-family furnaces (Heil, Comfortmaker, Arcoaire) that use the same 115V-to-24V 40VA control transformer. Verify the primary\/secondary voltages and VA rating against your existing unit before installing.\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 control compartment service panel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph the primary and secondary wire connections before disconnecting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Label and disconnect the 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 the primary (line) and secondary (24V) leads per your photo.\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 powers up and the furnace responds to a call for heat.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eBlank or dead thermostat with the furnace powered\u003c\/li\u003e\n\u003cli\u003eNo 24V control voltage measured at the board\u003c\/li\u003e\n\u003cli\u003eFurnace does not respond to a heat call\u003c\/li\u003e\n\u003cli\u003eRepeatedly blown control fuse or burnt transformer windings\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":63021766836595,"sku":"1012722-GEN","price":24.95,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048404599155,"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_19b12dec-78ae-4281-889c-fd38a6aab8e8.jpg?v=1782958298","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-40va-transformer-for-t8mpn100f20a1-furnace-115v-to-24v-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}