{"product_id":"icp-24v-transformer-for-zama017aha3-spst-40va-control-ships-today","title":"ICP 24V Transformer for ZAMA017AHA3 — SPST 40VA Control | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis OEM 24V control transformer (ICP part #1057251) provides the low-voltage power that runs the thermostat, relays, and control circuits in your air handler or furnace. Rated at 40VA, it steps line voltage down to a stable 24V for the SPST control loop. A failed control transformer kills the entire 24V circuit: the thermostat goes dark, relays and contactors will not energize, and the system will not start. Typical causes are a shorted secondary, an overloaded control circuit, or heat-related winding failure from voltage surges.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\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\u003ePart Number\u003c\/td\u003e\n\u003ctd\u003e1057251\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003eControl 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\u003eSecondary Voltage\u003c\/td\u003e\n\u003ctd\u003e24V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRating\u003c\/td\u003e\n\u003ctd\u003e40VA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSwitch Action\u003c\/td\u003e\n\u003ctd\u003eSPST\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cp\u003eDirect-fit replacement for ICP, Tempstar, Heil, and Comfortmaker equipment that uses the 1057251 control transformer, including model ZAMA017AHA3. Verify primary voltage and VA rating against the original part before installing.\u003c\/p\u003e\u003ch3\u003eInstallation Guide\u003c\/h3\u003e\u003col\u003e\n\u003cli\u003e\n\u003cstrong\u003eSafety First\u003c\/strong\u003e — Disconnect power and verify zero voltage with a multimeter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the control-box\/service panel to reach the transformer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph the primary and secondary wiring before disconnecting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Disconnect the leads, unbolt the transformer from its bracket, and remove it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Mount the new transformer and reconnect primary and secondary leads per your photo.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power and confirm 24V across the secondary and normal control operation.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eBlank thermostat or no 24V at the control board\u003c\/li\u003e\n\u003cli\u003eRelays and contactors fail to pull in\u003c\/li\u003e\n\u003cli\u003eLow-voltage fuse blows repeatedly\u003c\/li\u003e\n\u003cli\u003eTransformer is hot, buzzing, or scorched\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eShipping \u0026amp; Returns\u003c\/h3\u003e\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":63021431718259,"sku":"ZAMA017AHA3-GEN","price":34.0,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63047947485555,"sku":"ZAMA017AHA3","price":44.2,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-transformer-control-ZAMA017AHA3.jpg?v=1782882042","url":"https:\/\/nationalhvacparts.com\/products\/icp-24v-transformer-for-zama017aha3-spst-40va-control-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}