Bard HVAC 8406-042BX Pressure Switch

The Bard 8406-042BX Pressure Switch is the direct engineering update for the legacy 8406-042, specifically designed for precise differential pressure sensing in Bard wall-mount units. Calibrated for a 0.28" PF pressure set point, this normally open air pressure switch monitors blower operation and heat pump airflow to prevent coil icing or compressor damage. For technicians diagnosing HVAC pressure switch failure, this component ensures the system maintains the correct static pressure before allowing the ignition or cooling sequence to proceed. The rugged diaphragm and snap-action electrical contacts are built to withstand the high-cycle demands of commercial HVACR applications. When replacing an older Bard pressure switch, the 8406-042BX provides the exact electrical compatibility and physical mounting footprint required for a fast, reliable HVAC part replacement without the need for field modifications or bracket fabrication.

• Precise Calibration: Factory-set at 0.28" WC to ensure accurate airflow monitoring and safety limit control.
• OEM Compatibility: Designed specifically for Bard HVAC systems, acting as the official successor to the 8406-042 model.
• Durable Construction: High-quality materials resist mechanical fatigue, ensuring stable pressure switch set points over long-term operation.
• Simplified Installation: Standard HVAC electrical connections and mounting holes enable rapid field swaps during service calls.

How do I test the Bard 8406-042BX for failure?
Use a manometer to verify the system is hitting the 0.28" PF pressure threshold while checking for continuity across the terminals with a multimeter. If the blower is running and static pressure is sufficient but the contacts remain open, the switch requires replacement.

Can this switch replace the older 8406-042?
Yes, the 8406-042BX is the updated version specifically engineered to replace the 8406-042 while maintaining the same technical specifications and performance standards.

What causes a pressure switch to trip in a Bard unit?
Common issues include a restricted air filter, failing indoor blower motor, or obstructed pitot tubes. Always clear the pressure sensing lines of debris before installing a new HVAC safety switch.

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.