Marley Engineered Products 4520-0011-000 Limit Switch

The Marley Engineered Products 4520-0011-000 Limit Switch is a high-precision 300F CU AUTO limit switch engineered for critical thermal protection in industrial and commercial heating applications. As a veteran-grade HVAC replacement part, this linear limit protector features an automatic reset mechanism that triggers at a 300°F threshold to prevent equipment overheating and potential component failure. The 4520-0011-000 is built with a rugged copper sensor and durable housing, making it a reliable high limit thermostat for demanding environments. Designed specifically for the Marley MUH series unit heaters, it ensures seamless integration with factory control circuits. This OEM limit switch provides the necessary snap-action response required for 5000W electric heaters and air handlers, maintaining strict safety parameters without the need for manual intervention after a trip event. Contractors value this Marley limit switch for its exact calibration and compatibility with models like the FHP and HUHAA series, ensuring long-term operational stability and system safety.

• Precision Thermal Safety: Fixed 300°F trip point provides reliable overheat protection for high-capacity heating coils.
• Automatic Reset Functionality: Eliminates the need for manual resets, reducing system downtime and service calls after temporary temperature spikes.
• Enhanced Compatibility: Direct factory replacement part for Marley, Berko, and QMark MUH series unit heaters.
• Rugged Copper Construction: High-grade CU limit switch sensing element offers superior thermal conductivity and corrosion resistance.
• Compact Linear Design: Low-profile linear limit protector allows for easy mounting within tight internal heater cabinets.

• Is this switch compatible with my MUH series heater? Yes, the Marley 4520-0011-000 is the standard OEM replacement for most Marley MUH-model heaters requiring a 300°F limit.
• How do I test a limit switch for continuity? Using a multimeter, check for a closed circuit (continuity) at room temperature; the 4520-0011-000 is normally closed and should only open when reaching the 300°F set point.
• What causes a limit switch to trip frequently? Common causes include restricted airflow, dirty filters, or a failing blower motor, which drive internal temperatures toward the 300°F safety limit.

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.