{"product_id":"carrier-py3gnaa30040aa-transformer-h30291","title":"OEM Carrier Transformer 40VA 208\/240V–24V for PY3GNAA30040AA","description":"\u003ch1\u003eOEM Carrier Control Transformer 40VA 208\/240V to 24V for Model PY3GNAA30040AA\u003c\/h1\u003e\u003cp\u003eThe Carrier HT01BD209 is the factory-specified 40VA step-down transformer for the \u003cstrong\u003ePY3GNAA30040AA\u003c\/strong\u003e HVAC system. This transformer is the heartbeat of the low-voltage control circuit — it steps 208\/240V line voltage down to the 24V AC signal that powers your thermostat, contactor coil, and control board. When it fails, the entire system goes dark: no thermostat response, no contactor click, no blower activation. If your system is completely unresponsive despite confirmed line voltage at the unit, a failed transformer is one of the first components to check.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e Input 208\/240V | Output 24V | 40VA rated | 50\/60Hz dual frequency | OEM part number HT01BD209\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM vs Generic:\u003c\/strong\u003e This is the genuine Carrier OEM transformer, wound to exact VA and voltage tolerances. Generic aftermarket units frequently run outside ±5% tolerance, which can cause nuisance tripped low-voltage fuses, erratic board behavior, or premature contactor coil failure.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall difficulty: 2\/5\u003c\/strong\u003e — Always shut off all power (line and low-voltage) before beginning. Photograph existing wiring connections before disconnecting. Tools needed: flathead and Phillips screwdrivers, wire stripper, multimeter (to verify 24V output post-install). Insulate all terminals after reassembly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 1-year OEM factory warranty. In stock and ships same business day from our warehouse.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Direct OEM replacement for Carrier model \u003cstrong\u003ePY3GNAA30040AA\u003c\/strong\u003e. Verify your unit's data plate shows 208\/240V primary control circuit before ordering. Our fitment team is available to confirm compatibility before you purchase — ships same day when ordered before 3PM EST.\u003c\/p\u003e","brand":"Carrier","offers":[{"title":"OEM","offer_id":62640460071283,"sku":"CARRIE-PY3GNAA30040AA-TRANSFORMER-HT01BD209","price":47.25,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62640460104051,"sku":"CARRIE-PY3GNAA30040AA-TRANSFORMER-HT01BD209-GEN","price":18.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-control-HT01BD209_774733fd-f7fc-4a12-8a3d-9e80251dbdd7.jpg?v=1782942371","url":"https:\/\/nationalhvacparts.com\/products\/carrier-py3gnaa30040aa-transformer-h30291","provider":"National HVAC Parts","version":"1.0","type":"link"}