Rheem-Ruud 42-24195-81 Pressure Switch

The Rheem-Ruud 42-24195-81 Pressure Switch is a critical safety component designed for precise induced draft monitoring in high-efficiency gas furnaces. Rated at .50" WC, this Single Pole Single Throw (SPST) switch ensures the inducer motor is pulling the correct vacuum before allowing the ignition sequence to proceed. Featuring a 1/4 barb connection for seamless integration with standard pressure tubing, this OEM replacement part prevents hazardous operation by opening the circuit if venting obstructions or mechanical failures occur. As an essential furnace safety switch, it provides the reliability needed for 24V control circuits in Rheem, Ruud, and Weather King systems. For professional contractors, diagnostic accuracy is improved by verifying the inches water column rating against manometer readings to confirm proper diaphragm actuation and prevent nuisance trips.

• OEM Precision: Genuine factory part ensures exact pressure switch calibration at .50" WC for safety compliance.
• Direct Fit: Standard 1/4 inch barb and electrical terminals allow for fast, drop-in replacement during service calls.
• Universal Compatibility: Engineered for use across multiple Rheem and Ruud furnace models, including Corsair and Weather King units.
• Durable Construction: High-grade diaphragm material prevents premature failure caused by heat or moisture cycles.

What causes a .50" WC pressure switch to stay open?

Common field issues include a restricted flue pipe, a failing inducer motor, or moisture buildup in the pressure tubing. Verify the vacuum with a manometer; if the pull exceeds .50" WC but the switch remains open, the internal diaphragm or contacts have likely failed.

Can I use a universal pressure switch instead of the 42-24195-81?

While adjustable switches exist, we recommend this specific OEM part to maintain the manufacturer's safety specifications. Incorrect pressure settings can lead to improper combustion or safety hazards.

How do I test the SPST circuit on this switch?

With the inducer running, use a multimeter to check for continuity across the terminals. If the inducer provides the required negative pressure and the switch does not close to complete the 24V circuit, the component requires replacement.

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.