{"product_id":"tempstar-defrost-control-board-for-txh518gka100-24v-heat-pump-ships-today","title":"Tempstar Defrost Control Board for TXH518GKA100 — 24V Heat Pump | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\n\u003cp\u003eThis OEM defrost control board (part #1173636) manages the defrost cycle on your Tempstar TXH518GKA100 heat pump. It monitors outdoor coil temperature and accumulated run time, then starts and stops defrost to clear frost from the outdoor coil during heating. During the cycle the board energizes the reversing valve, switches in auxiliary heat, and times the compressor and outdoor fan. It runs on a 24V control signal and coordinates the contactor, sensors, and reversing valve coil so defrost happens only when conditions require it. A failed defrost board commonly causes a heat pump that ices over, short cycles, or never switches into defrost — producing weak heat, frozen coils, and elevated energy use.\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 \/ Comfortmaker)\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 Defrost Control\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFit\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\u003eEngineered as a direct OEM fit for the Tempstar TXH518GKA100 heat pump and shared ICP-family platforms sold under the Heil, Comfortmaker, and Arcoaire badges using the same chassis. Verify your existing board's part number (1173636) and connector layout against the unit before ordering.\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 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 outdoor unit's electrical access panel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph every wire and connector position on the old board before disconnecting anything.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Unplug the low-voltage harness and sensor leads, release the mounting screws\/standoffs, and lift out the old defrost board.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Mount the new board, then reconnect each harness and sensor exactly per your photos.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power, run a heating call, and confirm the unit enters and terminates 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 and the unit never enters defrost.\u003c\/li\u003e\n\u003cli\u003eHeat pump short cycles or won't switch between heating and defrost.\u003c\/li\u003e\n\u003cli\u003eReversing valve or auxiliary heat fails to energize on a defrost call.\u003c\/li\u003e\n\u003cli\u003eVisible burn marks, corrosion, or no diagnostic LED activity on the board.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eShipping \u0026amp; Returns\u003c\/h3\u003e\n\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":63021626032499,"sku":"1173636-GEN","price":134.95,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048448606579,"sku":"1173636","price":175.44,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-control-board-defrost-1173636_c0475811-4dbe-4c68-980f-76a857fd7ee8.jpg?v=1782959983","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-defrost-control-board-for-txh518gka100-24v-heat-pump-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}