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This is the OEM defrost control board (part number 1173636) for the Tempstar T4H448GKC100 heat pump. The defrost control board governs the unit's defrost cycle — monitoring outdoor coil temperature and run time to decide when to melt accumulated frost and ice during heating. It also sequences the reversing valve, compressor, and auxiliary heat. A failed board commonly causes a frozen outdoor coil, a heat pump stuck in one mode, short-cycling, or a unit that ignores the thermostat. This direct-fit 24V OEM replacement restores factory-correct defrost timing and system control.
| Spec | Value |
|---|---|
| Part Number | 1173636 |
| Type | Defrost Control Board |
| Brand | Tempstar (ICP / Heil) |
| Control Voltage | 24V |
| Fitment | OEM, model-specific |
| For Model | T4H448GKC100 |
Engineered for the Tempstar T4H448GKC100 heat pump and shared across ICP-family condensing units (Heil, Comfortmaker, Tempstar) that originally used board 1173636. Confirm the OEM number on your existing board before ordering.
Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.