{"product_id":"icp-control-board-for-wph4604000rkb1-heat-pump-defrost-board-ships-today","title":"ICP Control Board for WPH4604000RKB1 — Heat Pump Defrost Board | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis genuine OEM control board (part 1178001) is the main circuit board that manages operation of your ICP Tempstar Heil WPH4604000RKB1 heat pump, including the defrost cycle that keeps the outdoor coil clear of ice in heating mode. The board reads the defrost thermostat and timer logic, energizes the reversing valve and outdoor fan, and sequences the compressor and auxiliary heat. When it fails, the heat pump may not defrost (allowing the outdoor coil to ice over), may not switch modes, may leave the fan or compressor running incorrectly, or may not respond to thermostat calls at all. Installing the exact OEM board restores correct sequencing and reliable defrost protection.\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\u003e1178001\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003eHeat Pump Defrost Control Board\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\u003eControl Voltage\u003c\/td\u003e\n\u003ctd\u003e24V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFits Model\u003c\/td\u003e\n\u003ctd\u003eWPH4604000RKB1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFitment\u003c\/td\u003e\n\u003ctd\u003eOEM Exact Replacement\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cp\u003eDirect factory replacement for the defrost control board in the ICP Tempstar Heil WPH4604000RKB1 heat pump and related ICP-family heat pumps using the same control platform. Confirm the printed part number 1178001 on your existing board 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 at the disconnect and breaker and verify zero voltage at the board with a multimeter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the heat-pump control-panel cover.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph every harness, sensor, and 24V connection before disconnecting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Unplug all connectors, release the board standoffs or screws, and lift out the old board.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Seat the new board and reconnect each connector exactly as photographed.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power and confirm normal heating, cooling, fan, and defrost operation.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eOutdoor coil ices over because the unit never enters defrost.\u003c\/li\u003e\n\u003cli\u003eHeat pump will not switch between heating and cooling.\u003c\/li\u003e\n\u003cli\u003eCompressor or outdoor fan runs at the wrong time.\u003c\/li\u003e\n\u003cli\u003eNo response to thermostat calls despite 24V control power.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eShipping \u0026amp; Returns\u003c\/h3\u003e\u003cp\u003eShips same day on orders placed before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.\u003c\/p\u003e","brand":"ICP","offers":[{"title":"OEM","offer_id":63021481329011,"sku":"WPH4604000RKB1","price":227.5,"currency_code":"USD","in_stock":true},{"title":"Generic","offer_id":63047469891955,"sku":"WPH4604000RKB1-GEN","price":175.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-control-board-defrost-WPH4604000RKB1.jpg?v=1782885574","url":"https:\/\/nationalhvacparts.com\/products\/icp-control-board-for-wph4604000rkb1-heat-pump-defrost-board-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}