{"product_id":"tempstar-defrost-control-board-for-txh542gka100-oem-1173636-ships-today","title":"Tempstar Defrost Control Board for TXH542GKA100 — OEM 1173636 | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis is the OEM defrost control board (part 1173636) for the Tempstar TXH542GKA100 heat pump. The defrost board monitors outdoor coil temperature and run time, then commands a defrost cycle to melt frost off the outdoor coil during heating — reversing the valve, stopping the outdoor fan, and energizing auxiliary heat as needed. A failed board leaves the outdoor coil iced over (killing heating capacity), runs defrost too often or never, or causes the unit not to switch modes at all. The board also coordinates the contactor and reversing-valve coil, making it central to heat-pump operation.\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\u003eFunction\u003c\/td\u003e\n\u003ctd\u003eHeat-pump defrost timing \u0026amp; control\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eOutdoor heat pump section\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFitment\u003c\/td\u003e\n\u003ctd\u003eOEM direct replacement\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 TXH542GKA100 and matching ICP\/Heil heat-pump platforms using this defrost board. Match the part number and connector layout to the original 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 verify zero voltage with a multimeter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the outdoor unit control panel cover.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph every harness plug and the defrost sensor\/timer pin settings before disconnecting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Unplug each connector, note any jumper or DIP timer setting, and unclip the old board from its standoffs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Mount the new board, match the defrost timer\/jumper setting to the original, and reconnect every harness per your photo.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power, force a defrost (per the board's test pins), and confirm proper valve shift, fan stop, and timing.\u003c\/li\u003e\n\u003c\/ol\u003e\u003ch3\u003eSigns You Need a Replacement\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eOutdoor coil ices up and stays frozen in heat mode\u003c\/li\u003e\n\u003cli\u003eUnit never enters or never exits defrost\u003c\/li\u003e\n\u003cli\u003eNo outdoor operation despite a thermostat call\u003c\/li\u003e\n\u003cli\u003eVisible burn marks, swollen relays, or cracked 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":63021624983923,"sku":"1173636-GEN","price":149.0,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048449196403,"sku":"1173636","price":193.7,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-control-board-defrost-1173636_004090d9-c842-4914-8e35-9035bc13403b.jpg?v=1782960006","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-defrost-control-board-for-txh542gka100-oem-1173636-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}