{"product_id":"tempstar-defrost-control-board-for-t4h448gkc200-24v-heat-pump-control-ships-today","title":"Tempstar Defrost Control Board for T4H448GKC200 — 24V Heat Pump Control | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis is the OEM defrost control board (part number 1173636) for the Tempstar T4H448GKC200 heat pump. The defrost control board is the brain of the heat pump's defrost cycle — it monitors coil temperature and ambient conditions, then commands the unit into and out of defrost to clear frost and ice from the outdoor coil during heating operation. It also coordinates the reversing valve, compressor timing, and auxiliary heat staging. When this board fails, the heat pump may run continuously without defrosting, freeze the outdoor coil solid, short-cycle, fail to switch between heating and cooling, or stop responding to the thermostat entirely. This is a direct-fit 24V OEM replacement that restores correct, factory-spec defrost timing.\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\u003eFitment\u003c\/td\u003e\n\u003ctd\u003eOEM, model-specific\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFor Model\u003c\/td\u003e\n\u003ctd\u003eT4H448GKC200\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cp\u003eEngineered for the Tempstar T4H448GKC200 heat pump and shared across ICP-family condensing units (Heil, Comfortmaker, Tempstar) that originally shipped with board 1173636. Always confirm the OEM number printed 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 at the board with a multimeter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the control-panel service cover on the outdoor unit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph every wire and connector position before disconnecting anything.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Label and unplug the low-voltage harness and sensor leads, release the board standoffs, 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 every lead exactly as photographed, including the defrost thermostat\/sensor.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power, run a heating cycle, and confirm the unit initiates and terminates defrost correctly.\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 never defrosts during heating\u003c\/li\u003e\n\u003cli\u003eHeat pump won't switch between heating and cooling modes\u003c\/li\u003e\n\u003cli\u003eCompressor short-cycles or runs continuously\u003c\/li\u003e\n\u003cli\u003eNo 24V output to the reversing valve or contactor\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":"Tempstar","offers":[{"title":"Direct Replacement","offer_id":63021784269171,"sku":"1173636-GEN","price":135.0,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048445591923,"sku":"1173636","price":175.5,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-control-board-defrost-1173636_7a1257f4-186d-410e-86f6-3386f7588c09.jpg?v=1782959867","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-defrost-control-board-for-t4h448gkc200-24v-heat-pump-control-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}