{"product_id":"40va-120v-to-24v-transformer-universal-hvac-replacement","title":"40VA 120V to 24V Transformer — Universal HVAC Replacement","description":"\u003cp\u003e40VA control transformer stepping down from 120V to 24V AC. Universal replacement for standard residential furnaces. The transformer provides the low-voltage 24V power that runs your thermostat, control board, gas valve, and contactor coil — without it, your entire HVAC control circuit is dead.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhen to replace:\u003c\/strong\u003e No power to thermostat (blank screen), system completely unresponsive, burning smell from furnace, tripped breaker when system runs, buzzing from transformer with no 24V output, or measured secondary voltage below 22V.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eVA Rating:\u003c\/strong\u003e 40VA\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrimary (Input):\u003c\/strong\u003e 120V\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSecondary (Output):\u003c\/strong\u003e 24V AC\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Class 2 Control Transformer\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e standard residential furnaces\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMounting:\u003c\/strong\u003e Foot mount with screw terminals\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWarranty:\u003c\/strong\u003e 1-year replacement warranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eInstall difficulty: 2\/5\u003c\/strong\u003e — Turn off all power at breaker. Disconnect wires from old transformer (photograph first). Remove mounting screws. Mount new transformer, reconnect wires to matching terminals (primary to line voltage, secondary to 24V circuit). 15-25 minutes.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eSizing guide:\u003c\/strong\u003e A 40VA transformer handles most single-zone residential systems. If your system has multiple thermostats, zone dampers, or a communicating system, consider upgrading to 50VA or 75VA.\u003c\/p\u003e","brand":"National HVAC Parts","offers":[{"title":"Default Title","offer_id":63009905803635,"sku":"NHVAC-XFMR-40VA-120","price":19.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/71SikGp1t9L._SL500.jpg?v=1782105782","url":"https:\/\/nationalhvacparts.com\/products\/40va-120v-to-24v-transformer-universal-hvac-replacement","provider":"National HVAC Parts","version":"1.0","type":"link"}