Description
Lennox 30M03 Auto Limit Switch Overview
The Lennox 30M03 is an OEM-replacement automatic reset high-limit switch designed to protect furnaces and heating systems from dangerous overtemperature conditions. When supply air or heat exchanger temperatures rise beyond the rated threshold, this limit switch opens the circuit to shut down the burner — then automatically resets once temperatures return to a safe operating range, minimizing system downtime.
Key Features
- Auto (automatic) reset operation — no manual intervention required after a safe-temperature recovery
- Temperature range: 140°F to 170°F trip point for reliable high-limit protection
- Direct OEM replacement for compatible Lennox furnace models
- Protects heat exchangers and system components from thermal damage
- Durable construction built to withstand repeated heating cycles
How It Works
The limit switch continuously monitors the temperature within the furnace plenum or heat exchanger area. If temperatures exceed the set limit (up to 170°F), the switch opens and interrupts the burner circuit, preventing overheating. Once the unit cools to a safe level, the switch automatically resets and restores normal operation — no manual reset required.
Application
- Replacement limit switch for Lennox gas furnaces and heating systems
- Suitable for residential and light-commercial HVAC applications
- Installs in the furnace plenum or heat exchanger housing per OEM specifications
Why Choose the Lennox 30M03
Using a genuine Lennox OEM replacement limit switch ensures proper fit, accurate trip temperatures, and reliable safety performance. Aftermarket substitutes may not match the exact calibration or form factor required by your equipment. The 30M03 delivers peace of mind that your system will respond correctly to overtemperature events, protecting both the equipment and the occupants it serves.
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