OEM Guaranteed
Same-Day Ship
30-Day Returns
Secure Checkout
This OEM Tempstar defrost control board (part number 1173636) manages the defrost cycle on the T4H330GKD100 heat pump. In heating mode the outdoor coil collects frost, and the defrost board monitors coil temperature and run time, then commands a defrost — reversing the valve, shutting the outdoor fan, and energizing auxiliary heat — to melt accumulated ice. It also coordinates the contactor and reversing-valve solenoid through the low-voltage circuit. When this board fails, the outdoor coil ices over and stays iced, heating capacity drops, and the unit may lock out or run continuously without ever clearing frost. Erratic defrost timing, a unit stuck in defrost, or no defrost at all are classic symptoms of a failing board.
| Spec | Value |
|---|---|
| Part Number | 1173636 |
| Type | Defrost Control Board |
| Brand | Tempstar (ICP / Heil) |
| Control Voltage | 24V |
| Function | Defrost timing, reversing-valve & fan control |
| Application | Heat pump (outdoor section) |
Direct OEM replacement for the Tempstar T4H330GKD100 heat pump and related ICP-family (Heil, Comfortmaker) outdoor units that originally used defrost board 1173636. Verify the board part number printed on your existing board before ordering, as defrost logic and pin-outs vary by model.
Ships same day on orders placed before 3 PM CST. 30-day returns on unused parts. Backed by the National HVAC Parts fitment guarantee.