{"product_id":"tempstar-defrost-control-board-for-t4h318gkd300-oem-1173636-heat-pump-board-ships-today","title":"Tempstar Defrost Control Board for T4H318GKD300 — OEM 1173636 Heat Pump Board | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\n\u003cp\u003eThis is a genuine OEM defrost control board (part number 1173636) for the Tempstar T4H318GKD300 heat pump condensing unit. The defrost control board manages the entire defrost cycle — it reads outdoor coil temperature and tracks compressor run time, then temporarily reverses the system into cooling mode to clear frost and ice from the outdoor coil during cold-weather heating. It sequences the reversing valve, condenser fan, and compressor so the unit recovers efficiently and protects itself. A failed board commonly leaves the coil iced solid, kills heating output, or causes nuisance compressor lockouts. Operating on 24V control logic, this is a direct factory replacement.\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\u003e24V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eHeat Pump Defrost Cycle\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\n\n\u003ch3\u003eCompatibility\u003c\/h3\u003e\n\u003cp\u003eDirect-fit OEM replacement for the Tempstar T4H318GKD300 heat pump. The 1173636 board is also used across many ICP-family (Tempstar, Heil, Comfortmaker, Arcoaire) heat pump models sharing this control platform. Verify your existing board's part number 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 outdoor disconnect and verify zero voltage with a multimeter before handling any wiring.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the condenser unit's control-panel access cover.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph every wire and terminal on the existing board before disconnecting.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Label and disconnect the low-voltage and sensor leads, release the board standoffs or screws, and lift out the old board.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Mount the new 1173636 board and reconnect each lead exactly as shown in your photos, including the defrost sensor.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power, confirm normal heating, and verify the board initiates and ends a defrost cycle correctly.\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 freezes over and the unit never defrosts\u003c\/li\u003e\n\u003cli\u003eSystem won't enter defrost, or stays stuck in defrost\u003c\/li\u003e\n\u003cli\u003eCompressor short-cycles or locks out during heating\u003c\/li\u003e\n\u003cli\u003eScorched, corroded, or visibly damaged board components\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":63021802914163,"sku":"1173636-GEN","price":129.0,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048440381811,"sku":"1173636","price":167.7,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-control-board-defrost-1173636_cc5183b9-0cbc-40ac-a7a2-43497d18686b.jpg?v=1782959690","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-defrost-control-board-for-t4h318gkd300-oem-1173636-heat-pump-board-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}