ICP Furnace Control Board for RGS121LTCA0AAA — OEM Kit 1183618 | Ships Today

Overview

This genuine OEM control board kit, part number 1183618, is the integrated furnace control (IFC) for the ICP / Tempstar / Heil RGS121LTCA0AAA gas furnace. The board is the brain of the furnace: it sequences the inducer motor, energizes the hot surface igniter, opens the gas valve, monitors flame via the sensor, and times the blower on and off. It also runs the diagnostic LED fault codes. When this board fails — often from line-voltage surges, a cracked relay solder joint, or a blown onboard fuse — the furnace may be completely dead, short-cycle, or run the blower continuously.

Specifications

Compatibility

Direct OEM replacement for the RGS121LTCA0AAA furnace and the matching Tempstar, Heil, and Comfortmaker units sharing this control platform. Confirm the printed board number 1183618 on your existing board before ordering.

Installation Guide

1. Safety First — Disconnect power at the furnace switch and verify zero voltage with a multimeter.
2. Access — Remove the blower-compartment service panel.
3. Document — Photograph every wire and connector position on the existing board.
4. Remove — Label and unplug each harness, remove the mounting screws, and lift out the old board.
5. Install — Mount the new board, transfer connectors one at a time to match your photo, and set any DIP/jumper settings identically.
6. Test — Restore power and run a full heat cycle; verify ignition, flame sense, and blower timing, and check the diagnostic LED for steady operation.

Signs You Need a Replacement

• Furnace completely unresponsive with no LED activity
• Short-cycling or random shutdowns
• Blower runs constantly or never starts
• Diagnostic LED shows a hard fault that persists after resetting other components

Shipping & Returns

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