Description
The Armstrong Furnace R102857-20 is an OEM replacement L140-30F limit control designed to protect your furnace from overheating and heat exchanger damage. As a critical safety component, this limit switch monitors supply-air temperature and interrupts the burner circuit when temperatures reach unsafe levels, then automatically resets once conditions return to normal operating range.
How It Works
The L140-30F designation identifies this as a limit control with a 140°F open (trip) set point and a 30°F fixed differential, meaning the control opens at 140°F and automatically resets at approximately 110°F. When airflow is restricted — due to a dirty filter, blocked return, or blower failure — temperatures rise and the limit control cuts power to the burner, preventing damage and potential hazards.
Key Features
- OEM Armstrong Furnace replacement part — ensures proper fit and reliable performance
- L140-30F designation: opens at 140°F, resets at approximately 110°F (30°F differential)
- Automatic reset operation for convenient, hands-free recovery
- Protects heat exchanger from thermal stress caused by overheating
- Direct drop-in replacement for compatible Armstrong furnace models
- Durable construction built to meet OEM specifications
Application
- Designed for use in Armstrong Furnace systems requiring the L140-30F limit control
- Ideal for HVAC technicians performing maintenance, service, or safety control replacement
- Always verify compatibility with your specific furnace model before installation
Why Replace Your Limit Control?
A faulty or worn limit control can cause nuisance shutdowns, prevent the furnace from firing, or — in a worst-case failure — allow the system to overheat. Replacing with a genuine OEM Armstrong part ensures the control operates within the original design parameters, maintaining system safety and efficiency.
Order the Armstrong Furnace R102857-20 L140-30F Limit Control from Jackson Systems for fast shipping and expert support.
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