Armstrong Furnace R100684-04 Pressure Switch

The Armstrong Furnace R100684-04 Pressure Switch is a critical safety component engineered for precise inducer motor verification and flue gas management. This OEM replacement part is factory-calibrated to a .65"wc set point, ensuring the combustion blower is generating the necessary static pressure before allowing the ignition sequence to proceed. As a SPST (Single Pole Single Throw) switch, it provides a reliable normally-open circuit that closes upon sensing the correct vacuum via the 1/4" barb connection.

Designed for seamless integration with Armstrong and Allied Air furnaces, the R100684-04 bypasses the reliability issues of universal alternatives. Its rugged construction is built to withstand the high-temperature environment of the burner cabinet while maintaining tight tolerances to prevent nuisance tripping or pressure switch stuck open codes. For contractors, this is a drop-in solution that restores HVAC system safety and energy efficiency without requiring field adjustments. Ensure the pressure switch tubing is clear of moisture and the collector box is free of obstructions during installation to maintain optimal performance.

• Exact OEM Calibration: Pre-set at .65"wc to match specific Armstrong furnace specs, reducing troubleshooting time on-site.
• Industrial-Grade SPST Contacts: High-quality electrical terminals designed to handle inductive loads without premature pitting or failure.
• Standard 1/4" Barb: Features a universal-fit hose connection for quick replacement of original sensing lines.
• System Safety Integrity: Vital for detecting venting obstructions or failed inducer motors to prevent hazardous operation.
• HVAC Efficiency: Maintains the correct air-to-fuel ratio by ensuring the burner only fires under proper draft conditions.

How do I test if the R100684-04 is failing?
Using a manometer, verify that the inducer is pulling at least .65"wc and check for electrical continuity across the terminals when the vacuum is applied. If the blower reaches the set point but the contacts remain open, the switch requires replacement.

What causes a "pressure switch stuck open" error code?
While the switch itself may be faulty, always check for cracked pressure tubing, a clogged inducer port, or a blocked vent pipe before replacing the component.

Is this switch compatible with other Allied Air brands?
Yes, this unit serves as a direct replacement for various Armstrong, AirEase, and Concord models requiring a .65"wc SPST configuration.

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.