OEM Guaranteed
Same-Day Ship
30-Day Returns
Secure Checkout
This OEM defrost control board (part #1173636) is the brain of the Tempstar T4H418GKB200 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.
| Spec | Value |
|---|---|
| Part Number | 1173636 |
| Type | Defrost Control Board |
| Brand | Tempstar (ICP) |
| Control Voltage | 24 VAC |
| Function | Defrost timing, reversing valve & fan control |
Direct OEM fit for the Tempstar T4H418GKB200 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.
Ships same day on orders placed before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.