Lennox 25J30 Limit Switch

The Lennox 25J30 is a heavy-duty, disc-style OEM furnace limit switch engineered for high-precision thermal monitoring in residential and light commercial air handlers. This SPST normally closed control is a direct drop-in replacement for the Lennox 25J3001 and is critical for maintaining safe plenum temperatures. Designed with an automatic reset function, the switch triggers a circuit break when temperatures reach the 155°F cutout point, effectively preventing cabinet overheating and potential heat exchanger damage. Once the system cools to the 125°F cut-in threshold, the 25J30 limit control automatically resets the circuit to resume normal heating cycles. For techs troubleshooting Lennox G23 series or Armstrong furnace models, this 125-155F limit switch ensures accurate thermal protection and long-term reliability without the nuisance tripping often associated with aftermarket equivalents. Integrating this genuine Lennox part restores the system's safety sequence and protects high-value components from excessive thermal stress.

• Precise Thermal Regulation: Features a fixed 155°F open and 125°F close range for consistent plenum temperature management.
• Direct OEM Compatibility: Specifically designed to replace Lennox 25J3001 and various Allied and Armstrong part numbers.
• Automatic Reset Logic: Eliminates the need for manual intervention after a temporary overheat condition once temperatures normalize.
• Simplified Installation: Standard 2-pin spade terminal configuration allows for rapid field replacement in tight heat exchanger cabinets.
• Durable Disc Design: Robust construction withstands high-cycle frequency in demanding 125-155F environments.

Is the Lennox 25J30 interchangeable with the 25J3001?
Yes, the 25J30 and 25J3001 are functionally identical and share the same thermal specifications and mounting footprint.

What causes this limit switch to trip repeatedly?
While the switch is a safety device, frequent tripping usually indicates restricted airflow due to a dirty filter, failing blower motor, or blocked ductwork.

Does this switch require manual resetting?
No, this model features an auto-reset mechanism that restores continuity once the sensor detects the 125°F cut-in temperature.

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.