{"product_id":"carrier-ph3zpa042000aa-transformer-h3025m","title":"OEM Carrier Control Transformer 40VA 120V→24V — PH3ZPA042000AA","description":"\u003ch1\u003eOEM Carrier Control Transformer 40VA 120V\/24V for Model PH3ZPA042000AA\u003c\/h1\u003e\u003cp\u003eThis is the factory OEM replacement control transformer (part number \u003cstrong\u003eHT01BD242\u003c\/strong\u003e) for the \u003cstrong\u003eCarrier PH3ZPA042000AA\u003c\/strong\u003e packaged heat pump unit. The transformer steps down 120V line voltage to the 24V control circuit voltage that powers your thermostat, contactor coils, and all low-voltage safety controls. When this part fails, the entire control circuit goes dead — the thermostat loses power, nothing responds, and the system won't heat or cool at all. A failed transformer is often confirmed by checking for 24V output with a multimeter; if you read 0V on the secondary with 120V confirmed at the primary, this transformer is your culprit.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e 120V primary input | 24V secondary output | 40VA rated | OEM part number HT01BD242 | Factory-matched for Carrier PH3ZPA042000AA\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM vs Generic:\u003c\/strong\u003e This is the genuine OEM Carrier transformer — factory-wound to exact VA and voltage specifications. Generic transformers may deliver inconsistent 24V output, causing nuisance lockouts, relay chatter, or premature contactor coil failure.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall difficulty: 2\/5\u003c\/strong\u003e — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Label or photograph all 24V wiring connections before removal. Verify 120V input is dead before touching primary terminals.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 1-year OEM factory warranty against defects. Ships same business day from our warehouse when ordered before cutoff.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Engineered for Carrier model \u003cstrong\u003ePH3ZPA042000AA\u003c\/strong\u003e packaged heat pump systems. Always verify your existing transformer's VA rating and primary\/secondary voltages on the data plate or unit wiring diagram before ordering. Our fitment team is available to confirm compatibility before you buy — reach out before placing your order.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62641318625651,"sku":"CARRIE-PH3ZPA042000AA-TRANSFORMER-HT01BD242","price":34.95,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62641318658419,"sku":"CARRIE-PH3ZPA042000AA-TRANSFORMER-HT01BD242-GEN","price":30.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-HT01BD242_31fd1907-bb69-4a1f-b718-e871bbdbe472.jpg?v=1775025406","url":"https:\/\/nationalhvacparts.com\/products\/carrier-ph3zpa042000aa-transformer-h3025m","provider":"National HVAC Parts","version":"1.0","type":"link"}