Bard 8402-078BX Limit Control

The Bard 8402-078BX Limit Control is a critical safety component designed for high-performance temperature regulation in HVAC systems, specifically for Bard wall-mount units, furnaces, and heat pumps. This OEM replacement part serves as the updated successor to the 8402-078, maintaining exact L175-30 mechanical specifications to ensure a seamless drop-in fit for field repairs. Featuring a 7-inch probe length, this high-limit switch accurately monitors heat exchanger temperatures to prevent thermal overstress and potential equipment failure.

Engineered for industrial-grade reliability, the Bard HVAC limit control operates with a fixed 175°F trip point and a 30°F differential. This normally closed (NC) switch opens the circuit upon reaching the 175°F threshold, effectively cutting power to the heating elements or burners until the system cools to 145°F and automatically resets. Utilizing a 7-inch thermal limit sensor, this device provides the precise sensing depth required to reach the optimal airflow path within the plenum, ensuring consistent HVAC safety switch performance and protecting your client's hardware from overheating during restricted airflow conditions.

Key Benefits

• Direct OEM Compatibility: Engineered as the official successor to part number 8402-078, ensuring 100% compatibility with original factory wiring and mounting.
• Enhanced System Safety: Provides a redundant thermal failsafe by interrupting the ignition or heating cycle if temperatures exceed the 175°F design limit.
• Precision Thermal Sensing: The 7-inch probe penetrates deep into the heat exchanger compartment for accurate, real-time temperature monitoring.
• Rugged Construction: Built to withstand the harsh environment of commercial air handlers, reducing the risk of premature fatigue or nuisance tripping.

Common Questions

Is the 8402-078BX a direct replacement for the older 8402-078 model?
Yes, the 8402-078BX is the manufacturer’s updated part number. It maintains the identical L175-30 profile and 7-inch probe depth, requiring no modifications to the existing bracket or electrical leads.

What does the "L175-30" designation mean for this limit control?
The "L" indicates it is a Limit control (normally closed, opens on rise). "175" is the cutout temperature in degrees Fahrenheit, and "30" represents the differential, meaning the switch will reset once the temperature drops by 30 degrees.

Can this switch be used in 24V or 120V control circuits?
This Bard limit control is designed for standard HVAC control circuits. Always verify your specific unit's wiring diagram, but it is typically utilized in series with the 24V gas valve or contactor coil circuit.

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.