{"product_id":"icp-40va-transformer-for-rgs303hrfa0aaaa-120-24v-class-2-ships-today","title":"ICP 40VA Transformer for RGS303HRFA0AAAA — 120\/24V Class 2 | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\n\u003cp\u003eThis OEM 40VA control transformer is the low-voltage power source for the ICP \/ Tempstar \/ Heil RGS303HRFA0AAAA gas furnace and its associated 24V relays (parts 1183814 and 1178205). The transformer steps 120V line power down to the 24V Class 2 control voltage that runs the thermostat, control board, gas valve, and switching relays. When it fails, the furnace goes completely dead — no thermostat display, no ignition, and no relay actuation. A transformer that hums loudly, runs hot, or has a blown internal fuse should be replaced to restore control power.\u003c\/p\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\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\u003eRelated Parts\u003c\/td\u003e\n\u003ctd\u003e1183814 (DPDT Relay), 1178205 (DPST Relay)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003eClass 2 Control Transformer\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eICP \/ Tempstar \/ 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\u003ePrimary Voltage\u003c\/td\u003e\n\u003ctd\u003e120V\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\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eGas Furnace Control Power\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eCompatibility\u003c\/h3\u003e\n\u003cp\u003eFits the ICP \/ Tempstar \/ Heil RGS303HRFA0AAAA gas furnace and parts-compatible RGS-series units using 120V primary \/ 24V secondary control power. Confirm your existing primary voltage tap and VA rating before installing.\u003c\/p\u003e\n\n\u003ch3\u003eInstallation Guide\u003c\/h3\u003e\n\u003col\u003e\n\u003cli\u003e\n\u003cstrong\u003eSafety First\u003c\/strong\u003e — Disconnect power at the switch and breaker, then verify zero voltage with a multimeter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the furnace control-compartment service panel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph the primary and secondary lead connections before disconnecting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Disconnect the leads, remove the mounting screws, and take out the failed transformer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Mount the new transformer, wire the 120V primary and 24V secondary exactly per your photos, and confirm correct tap selection.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power and verify a steady 24V output and normal furnace operation.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eFurnace is completely dead with no 24V control power.\u003c\/li\u003e\n\u003cli\u003eLoud humming, overheating, or burnt smell from the transformer.\u003c\/li\u003e\n\u003cli\u003eRepeatedly blown internal fuse or no secondary voltage reading.\u003c\/li\u003e\n\u003cli\u003eThermostat and relays unresponsive despite 120V at the primary.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eShipping \u0026amp; Returns\u003c\/h3\u003e\n\u003cp\u003eShips same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.\u003c\/p\u003e","brand":"ICP","offers":[{"title":"Direct Replacement","offer_id":63027275334003,"sku":"1183814-GEN","price":38.0,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63047951516019,"sku":"1183814","price":49.4,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-control-1183814_9949dc18-e26a-465f-926b-d72b03f995e9.jpg?v=1782882418","url":"https:\/\/nationalhvacparts.com\/products\/icp-40va-transformer-for-rgs303hrfa0aaaa-120-24v-class-2-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}