ICP Pressure Switch for WPG4364090LKA1 — Furnace Safety Switch | Ships Today

Overview

This is a genuine OEM pressure switch with tubing (OEM Part No. 1178417, "TUBING PRESSURE SWITCH") for the ICP / Tempstar / Heil WPG4364090LKA1 gas/electric packaged unit. The pressure switch is a critical combustion safety device. On a heat call, the inducer draft motor starts and creates negative pressure in the vent; the pressure switch senses that vacuum through its tubing and closes its contacts, proving to the control board that the flue is clear and venting properly before it allows the igniter and gas valve to energize. If the switch does not close — because of a blocked flue, a failed inducer, a cracked hose, or a faulty switch — the board safely blocks ignition to prevent a dangerous combustion event. This is the part that protects against carbon-monoxide hazards from improper venting. Because the switch and its hose are exposed to condensate, soot, and constant cycling, they are common no-heat failure points. Typical symptoms include a furnace that runs the inducer but never lights, repeated "pressure switch" fault codes at the board, and a switch whose contacts stick open or closed.

Specifications

Compatibility

This pressure switch assembly is the factory-specified draft safety switch for the ICP / Tempstar / Heil WPG4364090LKA1 packaged unit and is shared across many ICP-family gas/electric and furnace platforms. Match the switch's pressure set point (in. w.c.) and port configuration to your original before installing — set points differ by model and altitude.

Installation Guide

1. Safety First — Shut off gas and disconnect power, then verify zero voltage at the switch terminals with a multimeter.
2. Access — Remove the burner/control compartment panel to reach the switch and inducer.
3. Document — Photograph the wiring and the tubing routing between the switch and the inducer port.
4. Remove — Pull the spade terminals, disconnect the sensing tube, and unscrew the switch from its bracket.
5. Install — Mount the new switch, reconnect the tubing so it is kink-free and condensate-draining, and reattach the wires per your photo.
6. Test — Restore gas and power, start a heat call, and confirm the inducer pulls the switch closed and the burners light normally.

Signs You Need a Replacement

• Inducer runs but the furnace never lights the burners.
• Control board flashes a pressure-switch fault code.
• Switch contacts stuck open (no heat) or stuck closed (unsafe, bypasses proving).
• Cracked, clogged, or condensate-filled sensing tube.

Shipping & Returns

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