Tempstar Control Board Comfort Alert for T2A348GKD100 — ICM Defrost/Diagnostic Board | Ships Today

Overview

This OEM Comfort Alert control board (part number 1177402) is the primary defrost and diagnostic control for the Tempstar T2A348GKD100 heat pump. It manages the defrost cycle, monitors compressor and fan operation, and reports fault conditions through onboard diagnostic LEDs. When this board fails, the unit may stop cycling, ice over in heating mode, fail to energize the contactor, or display erratic diagnostic codes. A failed control board is one of the most common causes of a no-cool / no-heat condition on this platform.

Specifications

Compatibility

Directly fits the Tempstar T2A348GKD100 and shares the ICP/Heil/Comfortmaker platform that uses the same Comfort Alert control assembly. Always confirm the printed part number 1177402 on your existing board before ordering.

Installation Guide

1. Safety First — Disconnect power at the disconnect and breaker, then verify zero voltage at the board with a multimeter.
2. Access — Remove the condenser control-panel access cover.
3. Document — Photograph every wire and connector position on the board before disconnecting anything.
4. Remove — Unplug the low-voltage harnesses, release the mounting standoffs/screws, and lift the old board out.
5. Install — Seat the new 1177402 board on the standoffs and reconnect each harness exactly per your photo.
6. Test — Restore power, confirm the diagnostic LED shows normal status, and verify the unit cycles and defrosts correctly.

Signs You Need a Replacement

• Unit will not start or contactor never energizes despite a thermostat call.
• Heat pump ices over because the defrost cycle no longer initiates.
• Comfort Alert / diagnostic LED is dark, frozen, or flashing a board fault.
• Intermittent shutdowns or burnt-smelling, scorched traces on the board.

Shipping & Returns

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