Tempstar Defrost Control Board for T4H324GKD200 — OEM 1173636 | Ships Today

Overview

The OEM defrost control board (part number 1173636) is the logic center that manages the defrost cycle on your Tempstar T4H324GKD200 heat pump. In heating mode, frost and ice build up on the outdoor coil; this board tracks elapsed run time and coil temperature, then triggers a timed defrost cycle—temporarily reversing refrigerant flow and bringing on auxiliary heat—to clear the ice and keep the system efficient. A failed board can no longer start or end defrost correctly, resulting in a coil that freezes solid, weak heating, a unit that runs nonstop, or one that never defrosts. This is among the most common reasons a heat pump stops heating in cold weather.

Specifications

Compatibility

This control board is the factory-specified replacement for the Tempstar T4H324GKD200 heat pump and serves as the OEM board on closely related ICP, Heil, and Comfortmaker models in the same family. Confirm your existing board's part number before ordering.

Installation Guide

1. Safety First — Disconnect power at the disconnect and breaker, then verify zero voltage with a multimeter.
2. Access — Remove the outdoor unit's control-panel service cover.
3. Document — Photograph every wire and terminal on the existing board before disconnecting anything.
4. Remove — Label and disconnect the leads, release the mounting standoffs, and lift out the old board.
5. Install — Seat the new board on the standoffs and reconnect each wire exactly as photographed.
6. Test — Restore power and verify the unit initiates and terminates a defrost cycle normally.

Signs You Need a Replacement

• Outdoor coil ices over and the unit never defrosts
• Heat pump runs continuously but delivers little or no heat
• Defrost cycle runs too often or won't terminate
• Auxiliary/emergency heat never engages during defrost

Shipping & Returns

Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.