Nordyne 632443R Pressure Switch

The Nordyne 632443R is a critical OEM replacement pressure switch designed for induced draft furnaces. Engineered to monitor the differential pressure between the draft inducer motor and the flue, this SPST (Single Pole Single Throw) switch is factory-calibrated to a precise -0.85" WC (Water Column) trip point. It features a 1/4" barbed connection for standard pneumatic tubing and two-terminal electrical contacts for direct furnace control board integration. Reliability at this vacuum threshold is essential to ensure the combustion air blower is clearing exhaust gases effectively before the ignition sequence begins, preventing hazardous recirculation or nuisance lockouts during high-demand cycles.

Key Benefits

• Ensures accurate combustion air proving by maintaining a -0.85" WC set point for system safety.
• Heavy-duty SPST switch construction designed to withstand the high-temperature environment of the furnace blower compartment.
• Compatible with a wide range of Nordyne, Intertherm, and Miller gas-fired equipment, ensuring a drop-in OEM fit.
• Quick-connect 1/4 inch barbed port simplifies the replacement of brittle or cracked vacuum lines during service calls.
• Prevents ignition failure and furnace short cycling caused by inadequate negative pressure in the heat exchanger.

Common Questions

What causes a -0.85" WC pressure switch to fail open?
While the Nordyne 632443R is robust, common field failures often stem from moisture in the sensing tube, a restricted flue vent, or a failing inducer motor that cannot achieve the necessary vacuum. Always check for obstructions before condemning the switch.

Can I use this switch for high-altitude furnace conversions?
This specific 632443R pressure switch is calibrated for standard sea-level venting. High-altitude applications generally require specific kits to account for lower air density; verify your manometer readings and furnace data plate before installing.

How do I verify the electrical operation of an SPST pressure switch?
With the furnace powered down and the inducer motor off, the switch should be normally open. Once the motor reaches full RPM and creates a vacuum exceeding -0.85" WC, continuity across the terminals should be detected with a multimeter.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.