Tempstar Defrost Control Board for T4H330GKE100 — OEM 1173636 Heat Pump | Ships Today

Overview

This is a genuine OEM defrost control board (part number 1173636) for the Tempstar T4H330GKE100 heat pump. The defrost control board governs the unit's defrost cycle: it reads outdoor coil and ambient temperatures and periodically commands the heat pump into defrost to melt frost and ice from the outdoor coil during heating operation. It sequences the reversing valve, condenser fan, and timing intervals so the coil stays clear and the system holds its heating efficiency in cold weather. When this board fails, the heat pump can run with a frosted or fully iced outdoor coil, fail to start or terminate defrost, short-cycle between modes, or lose heating capacity. Running on a 24V low-voltage control circuit, this board is a direct factory replacement that restores correct defrost timing and sequencing.

Specifications

Compatibility

Engineered for the Tempstar T4H330GKE100 heat pump and shared ICP-family platforms sold under the Heil, ICP, and Comfortmaker brands that use the same factory control architecture. Always confirm the printed part number 1173636 against your existing board 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 cover to expose the board.
3. Document — Photograph every wire and terminal connection before disconnecting anything.
4. Remove — Label and unplug each low-voltage and sensor lead, release the board's mounting standoffs or screws, and lift the old board out.
5. Install — Mount the new 1173636 board, then reconnect every wire and the coil sensor exactly per your photos.
6. Test — Restore power and initiate a test defrost cycle to confirm correct sequencing and termination.

Signs You Need a Replacement

• Outdoor coil ices over and never goes into defrost.
• Unit stays stuck in defrost or short-cycles between modes.
• Loss of heating capacity in cold weather.
• No 24V output to the reversing valve or fan during the defrost call.

Shipping & Returns

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