Tempstar Defrost Control Board for T2H342GKA100 — 24V Heat Pump Board | Ships Today

Overview

This OEM defrost control board (part number 1173636) is the brain of the defrost cycle in your Tempstar T2H342GKA100 heat pump. In heating mode, frost builds on the outdoor coil; the board monitors the defrost thermostat and a timed interval, then reverses the system and shuts the outdoor fan to melt that ice before returning to normal heating. It also coordinates the reversing valve and compressor relay logic. When this board fails, the heat pump either never defrosts — icing over and losing heating capacity — or gets stuck in a constant defrost loop, blowing cold air and spiking energy use.

Specifications

Compatibility

Direct OEM replacement for the Tempstar T2H342GKA100 heat pump. The 1173636 defrost board is shared across many ICP-family heat pumps (Tempstar, Heil, Comfortmaker). Match the part number and connector layout to your existing board before installing.

Installation Guide

1. Safety First — Disconnect power at the disconnect and breaker; verify zero voltage at the board with a multimeter.
2. Access — Remove the condenser unit's electrical access panel.
3. Document — Photograph every connector, jumper, and DIP/timer pin setting on the old board.
4. Remove — Unplug each harness, free the board's mounting standoffs or screws, and lift it out.
5. Install — Seat the new board, set the defrost timer pin to match the original, and reconnect each harness per your photo.
6. Test — Restore power, run a heating call, and confirm normal operation and a clean forced-defrost cycle.

Signs You Need a Replacement

• Outdoor coil ices over and heating output drops
• Unit stuck in continuous defrost, blowing cold air
• Defrost cycle never initiates regardless of frost
• No 24V output to the reversing valve or fan relay

Shipping & Returns

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