Marley Engineered Products 4520-2017-000 Limit Switch

The Marley Engineered Products 4520-2017-000 Limit Switch is a critical safety component designed for high-temperature HVAC equipment diagnostics and protection. This 300F M/R Limit Switch features a manual reset mechanism, ensuring that once the thermal threshold of 300 degrees Fahrenheit is reached, the circuit remains open until an on-site technician can inspect the system for the underlying cause of overheating. Engineered for reliability in industrial heating environments, the 4520-2017-000 is built with a heavy-duty enclosure and sealed terminals to resist moisture, dirt, and electrical contaminants that lead to premature failure in the field.

For contractors servicing Berko, QMark, or Marley air handlers and heat exchangers, this 300 degree limit switch is the direct OEM replacement part needed to maintain system integrity. Its precise calibration prevents catastrophic equipment failure by accurately monitoring the heat chamber. When you are performing a furnace flame rollout inspection or a wide-scale safety control upgrade, utilizing this authentic 4520-2017-000 ensures compatibility with the manufacturer's original wiring and mounting specifications, reducing installation time and eliminating the risks associated with generic aftermarket alternatives.

• Precise Thermal Protection: Fixed 300°F trip point specifically calibrated for HVAC safety controls to prevent equipment damage.
• Manual Reset Security: Requires physical intervention to close the circuit, forcing a diagnostic check if a high-limit trip occurs.
• Durable Construction: Features a heavy-duty enclosure and sealed terminals to withstand harsh, high-cycle industrial conditions.
• Direct OEM Fit: Ensures seamless integration with Marley Engineered Products, Berko, and QMark heating units.

• Can this switch be used to replace an automatic reset limit? No, this is a manual reset limit switch. Replacing an auto-reset switch with an M/R model without consulting system schematics can lead to improper system cycling.
• Is this compatible with multiple brands? Yes, the 4520-2017-000 is frequently found in Berko, QMark, and other Marley-engineered air handlers and heaters.
• How do I reset the device? Once the temperature drops below the 300°F threshold, press the red reset button firmly until you hear a click to restore the normally closed 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.