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The OEM defrost control board (part #1173636) governs the defrost cycle on the Tempstar T4H318GKA200 heat pump. It reads coil temperature and run time, then triggers the reversing valve, outdoor fan, and supplemental heat to melt frost off the outdoor coil. A bad board commonly shows up as an outdoor unit caked in ice, a heat pump stuck in one mode, short-cycling, or no 24V output to downstream components. Replacing the board with this factory part restores proper defrost logic.
| Spec | Value |
|---|---|
| Part Number | 1173636 |
| Type | Defrost Control Board |
| Brand | Tempstar (ICP / Heil) |
| Control Voltage | 24V |
| Application | Heat Pump Outdoor Unit |
| Function | Timed / demand defrost control |
Factory replacement for the Tempstar T4H318GKA200 heat pump condenser, and shared across many same-era ICP-family heat pumps (Heil, Comfortmaker, Arcoaire). Confirm original part number 1173636 before ordering.
Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.