{"product_id":"tempstar-40va-24v-transformer-for-t4h330gkd100-class-ii-ships-today","title":"Tempstar 40VA 24V Transformer for T4H330GKD100 — Class II | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis OEM Tempstar control transformer steps the unit's line voltage down to the 24V Class II control circuit that powers the contactor coil, defrost board, and reversing-valve solenoid on the T4H330GKD100 heat pump. Rated at 40VA, it supplies the low-voltage signal that lets the thermostat and control board switch high-voltage loads. When a transformer fails — usually from a shorted control wire or a stuck contactor coil drawing excess current — the entire low-voltage system goes dead: no thermostat display, no contactor pull-in, and no call for cooling or heating. A blown transformer is one of the most common causes of a completely unresponsive outdoor unit.\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\u003eType\u003c\/td\u003e\n\u003ctd\u003eControl Transformer (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\u003eRating\u003c\/td\u003e\n\u003ctd\u003e40 VA\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\u003eClass\u003c\/td\u003e\n\u003ctd\u003eClass II low-voltage\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eHeat pump control circuit\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cp\u003eFits the Tempstar T4H330GKD100 heat pump and related ICP-family (Heil, Comfortmaker) systems using a 40VA 24V control transformer. Confirm the VA rating and the part number stamped on your existing transformer before ordering, as VA requirements vary by control package.\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 outdoor disconnect and verify zero voltage with a multimeter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the control-panel access cover.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph the primary and secondary leads before disconnecting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Disconnect the line-voltage primary and the 24V secondary leads, then unbolt the transformer from the panel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Mount the new transformer and reconnect primary and secondary per your photo, matching tap voltage.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power and confirm 24V across the secondary terminals with a meter.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eThermostat is completely blank or unresponsive\u003c\/li\u003e\n\u003cli\u003eNo 24V at the contactor coil; outdoor unit won't engage\u003c\/li\u003e\n\u003cli\u003eRepeated low-voltage fuse blows on the control board\u003c\/li\u003e\n\u003cli\u003eBurnt smell or scorch marks at the transformer body\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eShipping \u0026amp; Returns\u003c\/h3\u003e\u003cp\u003eShips same day on orders placed before 3 PM CST. 30-day returns on unused parts. Backed by the National HVAC Parts fitment guarantee.\u003c\/p\u003e","brand":"Tempstar","offers":[{"title":"Direct Replacement","offer_id":63021800259955,"sku":"1172574-GEN","price":32.0,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048400929139,"sku":"1172574","price":41.6,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-control-1172574_1f0c401b-3fb2-4ff9-a41c-62b75d2e060b.jpg?v=1782958177","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-40va-24v-transformer-for-t4h330gkd100-class-ii-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}