ICP Pressure Switch for WPG4424090RKB1 — Furnace Air-Proving Safety | Ships Today

Overview

This OEM pressure switch assembly with tubing (OEM 1178417) is the combustion-airflow safety on the ICP WPG4424090RKB1 packaged gas/electric unit. The switch senses the negative pressure created by the draft inducer; only when it proves adequate venting will it close and allow the control board to energize the igniter and gas valve. This prevents the furnace from firing if the flue is blocked or the inducer is weak. A failed switch — or a cracked, clogged, or disconnected sensing hose — leaves the furnace stuck after the inducer starts, often flashing a pressure-switch fault code.

Specifications

Compatibility

Direct fit for the ICP / Tempstar / Heil WPG4424090RKB1 packaged gas-electric unit. Match the OEM number 1178417 and the switch's pressure set-point before ordering — a switch with the wrong trip pressure will cause nuisance lockouts.

Installation Guide

1. Safety First — Disconnect power at the unit disconnect and verify zero voltage with a multimeter.
2. Access — Remove the service panel near the draft inducer.
3. Document — Photograph the wire terminals and the sensing-hose routing before disconnecting.
4. Remove — Pull the sensing hose, disconnect the spade terminals, and remove the mounting screws.
5. Install — Mount the new switch, reconnect the wires per your photo, and seat the tubing fully so there are no leaks or kinks.
6. Test — Restore power, run a heat cycle, and confirm the inducer starts, the switch closes, and the burners light without a lockout.

Signs You Need a Replacement

• Inducer runs but the furnace never ignites
• Control board flashes a pressure-switch fault code
• Furnace short-cycles or locks out intermittently
• Switch contacts fail to close even with good draft

Shipping & Returns

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