{"product_id":"tempstar-defrost-control-board-for-t4h448gkd100-oem-1173636-ships-today","title":"Tempstar Defrost Control Board for T4H448GKD100 — OEM #1173636 | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis OEM defrost control board (part #1173636) is the brain of the defrost cycle on your Tempstar T4H448GKD100 heat pump. It monitors coil temperature and run time, then commands the unit into defrost to clear ice from the outdoor coil and switches it back to heating once the coil is clear. When this board fails you'll see common symptoms like the outdoor unit freezing solid, the system stuck in defrost or never defrosting, the reversing valve not energizing, or no 24V output to the fan and compressor circuits. A faulty board can also cause intermittent no-heat calls in cold weather.\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\u003e1173636\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003eDefrost Control Board\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eTempstar (ICP\/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\u003eFit\u003c\/td\u003e\n\u003ctd\u003eOEM Direct Replacement\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eHeat Pump\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cp\u003eDirect OEM fit for the Tempstar T4H448GKD100 heat pump and other ICP-family (Heil, Comfortmaker, Tempstar) condensing units that originally shipped with board #1173636. Always confirm the OEM number on your existing board before ordering.\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, then verify zero voltage with a multimeter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the outdoor unit control-panel service cover.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph every wire and terminal position before disconnecting anything.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Label and unplug all connectors, release the standoffs\/screws, and lift out the old board.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Seat the new board on the standoffs and reconnect each wire exactly per your photo.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power, force a defrost (or use the test pins) and confirm the unit defrosts and returns to heating normally.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eOutdoor coil ices over and unit never defrosts\u003c\/li\u003e\n\u003cli\u003eSystem stuck in defrost mode continuously\u003c\/li\u003e\n\u003cli\u003eNo 24V output to reversing valve, fan, or compressor\u003c\/li\u003e\n\u003cli\u003eVisible burnt traces, scorched relays, or a fault LED on the board\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":"Tempstar","offers":[{"title":"Direct Replacement","offer_id":63021784138099,"sku":"1173636-GEN","price":98.0,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048445788531,"sku":"1173636","price":127.4,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-control-board-defrost-1173636_2a60bff4-8095-4cb3-be18-987710ba9095.jpg?v=1782959869","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-defrost-control-board-for-t4h448gkd100-oem-1173636-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}