{"product_id":"tempstar-defrost-control-board-for-t4h548gkd100-oem-1173636-heat-pump-board-ships-today","title":"Tempstar Defrost Control Board for T4H548GKD100 — OEM 1173636 Heat Pump Board | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\u003cp\u003eThis is a genuine OEM defrost control board (part number 1173636) for the Tempstar T4H548GKD100 heat pump. The defrost control board is the brain of the heat pump's defrost cycle — it monitors the outdoor coil temperature and accumulated run time, then triggers a defrost cycle to melt frost and ice off the outdoor coil during heating operation. It coordinates the reversing valve, outdoor fan, and auxiliary heat to keep the system running efficiently in cold weather. When this board fails, the unit may ice over completely, fail to switch into or out of defrost, short-cycle, or stop heating altogether. The board operates on a 24V control circuit and includes timing logic for the standard defrost intervals used on Tempstar heat pump platforms.\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\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eHeat Pump Outdoor Unit\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\u003eThis board is a direct OEM fit for the Tempstar T4H548GKD100 heat pump. It is also used across related ICP-family outdoor units (Heil, Comfortmaker, and other Tempstar models) that share the same defrost control platform. Always confirm the part number on your existing board matches 1173636 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 breaker, and verify zero voltage with a multimeter before touching any wiring.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the outdoor unit's electrical access panel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph every wire and connector on the existing board before disconnecting anything.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Label and unplug the wire harnesses, then remove the mounting screws and lift out the old defrost board.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Mount the new 1173636 board, reconnect each harness exactly per your photos, and confirm all connectors are fully seated.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power and verify the unit enters heating, and force a defrost cycle to confirm the board commands the reversing valve and fan 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 goes into defrost\u003c\/li\u003e\n\u003cli\u003eUnit gets stuck in defrost and won't return to heating\u003c\/li\u003e\n\u003cli\u003eNo 24V output to the reversing valve or outdoor fan\u003c\/li\u003e\n\u003cli\u003eVisible burn marks, corrosion, or scorched relays 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 on unused parts. Backed by the National HVAC Parts fitment guarantee.\u003c\/p\u003e","brand":"Tempstar","offers":[{"title":"Direct Replacement","offer_id":63021782172019,"sku":"1173636-GEN","price":149.0,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048446771571,"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_79647f5c-562b-413e-abc0-4a930f2b3817.jpg?v=1782959908","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-defrost-control-board-for-t4h548gkd100-oem-1173636-heat-pump-board-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}