Tempstar Defrost Control Board for T4H424GKC100 — OEM 1173636 | Ships Today

Overview

The defrost control board (OEM part 1173636) is the electronic brain of your Tempstar T4H424GKC100 heat pump's defrost cycle. It monitors outdoor coil temperature and run time, then reverses the system to melt frost and ice off the outdoor coil so the unit can keep pulling heat in cold weather. When this board fails, the heat pump may run constantly in defrost, never defrost at all (leaving the coil iced over), short-cycle, or stop heating entirely. This is a genuine 24V OEM control board built to the exact specifications of the original.

Specifications

Compatibility

Direct-fit replacement for the Tempstar T4H424GKC100 heat pump. This board is shared across many ICP-family heat pumps sold under the Tempstar, Heil, Comfortmaker, and ICP brands. Match the OEM number 1173636 on your existing board to confirm fitment.

Installation Guide

1. Safety First — Disconnect power at the disconnect and breaker, then verify zero voltage with a multimeter before touching any wiring.
2. Access — Remove the outdoor unit's control-panel service cover.
3. Document — Photograph every wire and connector on the old board before disconnecting anything.
4. Remove — Unplug the low-voltage harnesses, release the board's mounting standoffs or screws, and lift out the old defrost board.
5. Install — Mount the new 1173636 board, reconnect each harness exactly as photographed, and set any defrost-timing jumper to match the original.
6. Test — Restore power and verify the unit enters and exits a defrost cycle normally.

Signs You Need a Replacement

• Outdoor coil stays caked in ice or frost during cold-weather operation
• Heat pump runs in defrost constantly or never defrosts
• No heating output or repeated short-cycling
• Visible burn marks, corrosion, or a tripped/blown trace on the old board

Shipping & Returns

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