{"product_id":"tempstar-defrost-control-board-for-t4h442gkb100-oem-1173636-ships-today","title":"Tempstar Defrost Control Board for T4H442GKB100 — OEM 1173636 | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\n\u003cp\u003eThis genuine OEM defrost control board (Tempstar part number 1173636) is the brain of the defrost cycle in your Tempstar T4H442GKB100 heat pump. In heating mode, frost builds on the outdoor coil; this board monitors coil temperature and run time, then reverses the system into a brief defrost cycle to melt that ice and restore efficient heating. It coordinates the reversing valve, outdoor fan, and compressor timing, and provides the 24V control logic that keeps the sequence safe and on-schedule. When this board fails, the heat pump either skips defrost (coil ices over and heating output collapses) or gets stuck defrosting, wasting energy and blowing cold air indoors.\u003c\/p\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\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\u003e24 VAC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eHeat Pump Defrost Cycle Management\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFitment\u003c\/td\u003e\n\u003ctd\u003eOEM Replacement\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eCompatibility\u003c\/h3\u003e\n\u003cp\u003eDirect OEM replacement for the Tempstar T4H442GKB100 heat pump. As the factory 1173636 board, it is also used across compatible ICP-family heat pumps (Tempstar, Heil, Comfortmaker, Arcoaire) that specify this defrost control. Match your existing board's part number and terminal layout before installing.\u003c\/p\u003e\n\n\u003ch3\u003eInstallation Guide\u003c\/h3\u003e\n\u003col\u003e\n\u003cli\u003e\n\u003cstrong\u003eSafety First\u003c\/strong\u003e — Disconnect power at the outdoor disconnect and breaker, and verify zero voltage with a multimeter before touching the board.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the control\/electrical access panel on the condensing unit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph every wire and harness plug on the existing board before disconnecting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Unplug the harnesses, note the defrost timer\/jumper pin settings, and unsnap or unscrew the old board from its standoffs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Mount the new 1173636 board, set the defrost timing pins to match the original, and reconnect every harness per your photo.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power and run a heating call; verify the board steps through its sequence and initiates defrost normally.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eOutdoor coil ices over heavily and heating output drops.\u003c\/li\u003e\n\u003cli\u003eUnit never enters defrost, or stays stuck in defrost.\u003c\/li\u003e\n\u003cli\u003eReversing valve or outdoor fan won't switch on command.\u003c\/li\u003e\n\u003cli\u003eNo or erratic 24V control output to the contactor and valve.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eShipping \u0026amp; Returns\u003c\/h3\u003e\n\u003cp\u003eShips same day on orders placed before 3 PM CST. 30-day returns on unused parts. Backed by the National HVAC Parts fitment guarantee.\u003c\/p\u003e","brand":"Tempstar","offers":[{"title":"Direct Replacement","offer_id":63021785678195,"sku":"1173636-GEN","price":129.95,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048444510579,"sku":"1173636","price":168.94,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-control-board-defrost-1173636_0235c092-0008-42fc-93d9-dcf12addd190.jpg?v=1782959843","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-defrost-control-board-for-t4h442gkb100-oem-1173636-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}