{"product_id":"payne-pa3zpa042000aa-transformer-h30291","title":"OEM Payne Transformer 40VA 120V-24V for PA3ZPA042000AA","description":"\u003ch1\u003eOEM Payne 40VA Control Transformer for Model PA3ZPA042000AA\u003c\/h1\u003e\u003cp\u003eThis is the factory OEM replacement control transformer (part# \u003cstrong\u003eHT01BD209\u003c\/strong\u003e) for the \u003cstrong\u003ePayne PA3ZPA042000AA\u003c\/strong\u003e packaged air conditioning unit. The transformer steps down 120V line voltage to the 24V signal that powers your thermostat, control board, and all low-voltage switching circuits. When the transformer fails, the entire control circuit goes dark — your thermostat goes blank, the system won't respond to any call for heating or cooling, and you may measure zero voltage at the secondary terminals. It is one of the first components to check when nothing in the system responds.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecs:\u003c\/strong\u003e 40VA rated | Primary: 120V | Secondary: 24V | OEM part number HT01BD209 | Factory-matched for Payne PA3ZPA042000AA\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM vs Generic:\u003c\/strong\u003e This OEM transformer is wound to exact VA and insulation specifications required by the Payne control board. Generic transformers may be undersized in VA capacity, causing overheating, nuisance tripping of the internal thermal fuse, and premature failure — especially when multiple low-voltage accessories (humidifiers, zoning boards, UV lights) share the circuit.\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 (to verify 24V output after install). Photograph or label all wiring connections before removing the old unit. The transformer typically mounts to the control panel bracket with two screws.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 1-year OEM factory warranty against defects. In-stock units ship same business day when ordered before cutoff.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCompatibility:\u003c\/strong\u003e Designed specifically for the \u003cstrong\u003ePayne PA3ZPA042000AA\u003c\/strong\u003e packaged unit. Always verify the OEM part number HT01BD209 against your unit's wiring diagram or data plate before ordering. Need help confirming fitment? Our HVAC parts specialists verify compatibility before your order ships — no guesswork.\u003c\/p\u003e","brand":"Payne","offers":[{"title":"OEM","offer_id":62908868428147,"sku":"PAYNE-PA3ZPA042000AA-TRANSFORMER-HT01BD209","price":34.95,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":62908868460915,"sku":"PAYNE-PA3ZPA042000AA-TRANSFORMER-HT01BD209-GEN","price":30.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-HT01BD209_cdd5df67-ba26-4847-b72a-892865156919.jpg?v=1780718884","url":"https:\/\/nationalhvacparts.com\/products\/payne-pa3zpa042000aa-transformer-h30291","provider":"National HVAC Parts","version":"1.0","type":"link"}