Tempstar Control Board ComfortAlert for T4A342GKN200 — Diagnostic Defrost Board | Ships Today

Overview

This OEM ComfortAlert control board (part number 1177402) is the diagnostic defrost control for the Tempstar T4A342GKN200 heat pump. It manages the defrost cycle, monitors compressor operation, and reports fault codes through onboard LEDs so technicians can quickly diagnose system problems. When this board fails the unit may stop defrosting, short-cycle, lock out the compressor, or display erratic fault codes. Because it carries 24V control logic, a failed board commonly presents as a no-heat or no-cool condition even though the compressor and motor are healthy.

Specifications

Compatibility

Engineered for the Tempstar T4A342GKN200 and shared across many ICP-family heat pumps (Tempstar, Heil, Comfortmaker) that use the ComfortAlert platform. Always confirm the OEM number 1177402 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 condenser service panel.
3. Document — Photograph every wire and connector before disconnecting.
4. Remove — Release the low-voltage and line-voltage plugs, unclip or unscrew the board from its standoffs, and lift it out.
5. Install — Mount the new 1177402 board on the standoffs and reconnect each harness exactly per your photos.
6. Test — Restore power, watch the diagnostic LEDs for a normal status, and confirm a proper defrost and run cycle.

Signs You Need a Replacement

• Unit fails to enter or exit defrost mode
• Flashing or solid fault-code LEDs on the board
• Compressor lockout or repeated short-cycling
• No 24V output to the contactor with good incoming power

Shipping & Returns

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