{"product_id":"tempstar-defrost-control-board-for-t4h418gkb100-24v-heat-pump-ships-today","title":"Tempstar Defrost Control Board for T4H418GKB100 — 24V Heat Pump | Ships Today","description":"\u003ch3\u003eOverview\u003c\/h3\u003e\n\u003cp\u003eThis OEM defrost control board (part #1173636) is the brain of the Tempstar T4H418GKB100 heat pump's defrost cycle. Running on 24V control voltage, it monitors the defrost thermostat and timer to determine when frost has built up on the outdoor coil, then reverses the system and locks out the outdoor fan to melt the ice before returning to heating. It also coordinates the reversing valve and compressor timing. When this board fails, the heat pump may ice over solid, run continuously, fail to switch between heating and cooling, or short-cycle the compressor — all of which kill efficiency and can damage the compressor.\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)\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\u003eFunction\u003c\/td\u003e\n\u003ctd\u003eDefrost timing, reversing valve \u0026amp; fan control\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 fit for the Tempstar T4H418GKB100 heat pump and shared across compatible ICP \/ Heil \/ Comfortmaker single-stage heat pump platforms using this defrost board. Match the board's part number and connector layout to the unit 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, then verify zero voltage with a multimeter.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccess\u003c\/strong\u003e — Remove the control-panel service cover.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDocument\u003c\/strong\u003e — Photograph every plug, pin terminal, and the defrost thermostat connections before unplugging.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove\u003c\/strong\u003e — Unplug all harnesses and release the board from its standoffs\/screws.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall\u003c\/strong\u003e — Seat the new board on the standoffs and reconnect each harness exactly per your photo.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest\u003c\/strong\u003e — Restore power, confirm normal operation, and initiate a forced defrost (per the board's test pins) to verify the cycle.\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 never clears\u003c\/li\u003e\n\u003cli\u003eHeat pump won't switch between heating and cooling\u003c\/li\u003e\n\u003cli\u003eCompressor short-cycles or won't run in heat mode\u003c\/li\u003e\n\u003cli\u003eDefrost cycle never initiates or never terminates\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. Backed by the National HVAC Parts fitment guarantee.\u003c\/p\u003e","brand":"Tempstar","offers":[{"title":"Direct Replacement","offer_id":63021788922227,"sku":"1173636-GEN","price":149.95,"currency_code":"USD","in_stock":true},{"title":"OEM","offer_id":63048443003251,"sku":"1173636","price":194.94,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-control-board-defrost-1173636_1aa9663a-b8e2-414f-aaae-7332d3ef1314.jpg?v=1782959780","url":"https:\/\/nationalhvacparts.com\/products\/tempstar-defrost-control-board-for-t4h418gkb100-24v-heat-pump-ships-today","provider":"National HVAC Parts","version":"1.0","type":"link"}