{"product_id":"tempstar-defrost-control-board-for-t4h418gkd100-heat-pump-timer-ships-today","title":"Tempstar Defrost Control Board for T4H418GKD100 — Heat Pump Timer | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis is the OEM defrost control board (part number 1173636) for the Tempstar T4H418GKD100 heat pump. The defrost board manages the heat pump's defrost cycle — it monitors coil temperature and run time, then reverses the system to clear frost from the outdoor coil during cold-weather heating. It also coordinates the reversing valve, compressor, and outdoor fan timing. When this board fails, the system can frost over and lose heating capacity, run continuous or no defrost cycles, or fail to switch between heating and cooling. The board operates on a 24V control signal.\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\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\u003eT4H418GKD100\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eHeat Pump Defrost\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 T4H418GKD100 heat pump and shared across closely related ICP \/ Heil \/ Comfortmaker \/ Tempstar heat pump platforms that use the same control architecture. Always confirm the printed part number 1173636 against 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's 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 the low-voltage and line connections, 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 each wire to match your photo.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power and verify heating, cooling, and a forced defrost cycle operate 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 won't defrost in heating mode\u003c\/li\u003e\n\u003cli\u003eSystem runs constant or excessively frequent defrost cycles\u003c\/li\u003e\n\u003cli\u003eHeat pump won't switch between heating and cooling\u003c\/li\u003e\n\u003cli\u003eVisible scorching, corrosion, or burnt traces on the board\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":63021788332403,"sku":"1173636-GEN","price":119.95,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048443101555,"sku":"1173636","price":155.94,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-control-board-defrost-1173636_179fea34-9bfb-4c26-a248-c6558103f893.jpg?v=1782959784","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-defrost-control-board-for-t4h418gkd100-heat-pump-timer-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}